Growth and Development of the Khapra Beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae), on Different Food Substrates

Growth and Development of the Khapra Beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae), on Different Food Substrates | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Growth and Development of the Khapra Beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae), on Different Food Substrates Tanushree Barman, Bannya Ghosh, Shakila Khatun Bristy, Md. Saiful Islam, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8562917/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract The population dynamics of insect pests in stored products are fundamentally governed by the nutritional quality of their diet. This study quantitatively demonstrates how variations in food substrate directly regulate key life-history parameters, ultimately determining infestation potential and outbreak risk. In this study, we investigated the effect of different food substrates on the development, survival, and reproduction of Trogoderma granarium under controlled laboratory conditions. As results indicated, the significant variation in larval weight was observed across diets, with the highest weight attained on wheat flour and the lowest on barley flour. Pupal weight did not differ significantly among diets, indicating limited dietary influence on pupal mass. Larval and pupal developmental periods were significantly influenced by diet, with larvae showing the shortest development (15.00 ± 0.31 d) on cracked wheat and the longest (19.00 ± 0.63 d) on barley flour, whereas pupae developed fastest (5.00 ± 0.70 d) on wheat flour and slowest (8.00 ± 0.63d) on whole maize. Pupation success was highest on cracked wheat and lowest on cracked barley. Diet significantly influenced adult emergence and longevity, with maximum emergence on wheat flour and minimum emergence on barley flour, whereas adults exhibited the longest lifespan on cracked wheat and the shortest on barley flour. Diet significantly affected F₁ progeny production, with cracked wheat supporting the highest offspring numbers (92.10 ± 1.39%) and whole maize the lowest (20.20 ± 0.91%). Overall, the findings demonstrate that wheat-based substrates—especially cracked wheat—strongly promote the population growth of T. granarium , highlighting their importance in pest risk assessment and management strategies. Our research establishes that the nutritional matrix of a food substrate is a critical determinant, defining the carrying capacity and growth trajectory of insect pest populations within a commodity. Trogoderma granarium Khapra beetle growth and development food substrates post-harvest loss Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Introduction The khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae), is regarded as one of the most destructive pests of stored agricultural commodities (Arthur et al. 2019 ; Athanassiou et al. 2019 a; Ahmed, et al. 2025). Native to South Asia, it has spread to many parts of Africa, the Middle East, and other warmer regions, where it thrives under arid conditions (Athanassiou et al. 2019 a, Kavallieratos et al. 2016 ; Shah and Brower, 2025). Its inclusion in the list of “100 of the World’s Worst Invasive Alien Species” and as a major A2 quarantine pest by the European and Mediterranean Plant Protection Organization (EPPO) underscores its global economic significance (Viljoen, 1990 , EPPO, 2013 ; Wilches et al. 2019 ). Infestations can result in weight losses of stored grain up to 70% under severe conditions, coupled with qualitative deterioration due to contamination with larval skins, frass, and urticating hairs, which render the product unfit for human or animal consumption (Wilches et al, 2016 ; Athanassiou etal. 2019 b). One of the remarkable features of T. granarium is its high adaptability to a variety of food sources and storage environments (Cox and Simms, 1978 ; Athanassiou et al. 2019 a). The larvae can survive without food for extended periods—up to several years in diapause—and tolerate wide temperature fluctuations, making eradication extremely challenging (Burges, 1962 , Wilches et al. 2019 ). The pest attacks a broad range of stored products, including wheat, rice, maize, barley, sorghum, pulses, oilseeds, and various processed foods. However, the development rate, survival, and fecundity of the beetle vary considerably depending on the type and physical condition of the food substrate (Athanassiou et al. 2019 a, El Halafawy, N.A., et al. 2025). The physical form of the commodity, such as whether it is whole grain, cracked kernels, or finely milled flour, plays a crucial role in determining its suitability for T. granarium growth and reproduction (Borzoui et al. 2015 , Yadav and Srivastava, 2017 ). Whole grains offer a harder, intact seed coat that can restrict larval penetration, whereas cracked grains provide more accessible endosperm and germ tissues (Athanassiou et al. 2010 , 2016 ). Finely ground grain products or different types of flour may offer a higher surface area and easier access to nutrients but can also present physical constraints such as compaction, reduced aeration, or moisture absorption differences (Rao et al. 2004 ). Nutritional composition, particle size, and structural integrity of the substrate thus interact to influence the pest’s developmental biology (Agarwal et al. 1988 ) The growth and development of T. granarium are strongly influenced by the type and condition of the food substrate (Athanassiou et al. 2016 ; Bhattacharya and Pant, 1969 ). Different grain forms—whole cereals, cracked grains, and milled products—vary in their nutritional composition, surface area, and accessibility to feeding stages, potentially affecting larval development, pupation, and adult emergence (Rao et al. 2004 ; Rajput et al. 2015 ). Understanding the developmental biology of this pest under various food forms is essential for predicting population dynamics and designing effective management strategies. Although previous research has examined the biology of T. granarium on selected commodities, there is limited comprehensive information on its comparative performance across different physical forms of the same cereal commodity under controlled conditions (Naseri et al. 2023 , Al-Jboory and Al-Rawy 2021 , Gaur et al. 2022 , Goyal, et al. 2024 ). Understanding these differences is important for several reasons: (a) it aids in predicting the risk of population build-up in mixed storage systems where whole grains, partially processed products, and flours coexist (Kavallieratos et al. 2024 ), (b) it supports the development of more targeted monitoring and management strategies, including substrate-specific preventive measures (Kavallieratos et al. 2022 ), (c) it contributes to more accurate pest risk assessments for trade and quarantine purposes (Nayak and Collins, 2022). The present study was conducted to investigate the growth and development of T. granarium on three different forms of cereal substrates—whole grains, cracked grain fractions, and grain flour—under standardized laboratory conditions. Key developmental parameters such as larval duration, pupal period, adult emergence, and survival rates were recorded and compared. The results are expected to provide valuable insights into the substrate preferences and performance of T. granarium , thereby helping to improve storage management practices and pest control interventions in both domestic and commercial grain storage systems. Materials and Methods Insect Collection and Culture Establishment Larvae and adults of the khapra beetle, T. granarium , were collected from infested grain stocks in local markets across Rajshahi Metropolitan City, Bangladesh. The collected specimens were transported to the Entomology Laboratory, Department of Zoology, University of Rajshahi, and reared for two generations under controlled environmental conditions (32–35°C, 62–65% RH, and a 12:12 h light: dark photoperiod) in decontaminated 1 L plastic containers containing whole wheat grains. This pre-experimental rearing ensured genetic uniformity and adaptation to laboratory conditions. Preparation of diets Three grain type, such as wheat ( Triticum aestivum L.), barley ( Hordeum vulgare L.), and maize ( Zea mays L.) were purchased from regional markets and confirmed to be free from insect infestation. Each grain type was prepared in three physical forms: (i) whole grains (intact kernels), (ii) cracked grains (mechanically fractured kernels, 2–4 mm particle size using a roller mill), and (iii) powdered grains (finely ground material passed through a 500 µm sieve (Philips HL7756 grinder). All grain types underwent a two-step sterilization process: refrigeration at -20°C for 48 h to suppress microbial activity, followed by acclimatization at 25 ± 1°C for 24 h to stabilize moisture content. This resulted in nine diet treatments arranged in a 3 × 3 factorial design (grain type × physical form). Each treatment was replicated five times, yielding 45 experimental units. Experimentation Clean, disinfected plastic jars (150 ml) were used for the bioassays. Each jar was filled with 25 g of one of the nine prepared diet types, with five replicates per treatment. Young larvae (2–3 days old; average length 3.0 mm measured under a microscope) were individually handled, and 50 larvae were introduced into each jar. The jars were covered with gauze cloth secured with rubber bands and placed in an incubator set at 35°C and 62–65% RH. Larvae were monitored for 10–12 days to record larval duration and weight. Pupae were subsequently observed for 4–5 days to record pupal period, number, and weight. Adult beetles were sexed under a microscope, and relevant data were recorded. Five pairs of adults from each treatment were transferred to separate jars for F₁ progeny assessment. Adult emergence was monitored for 10–11 days to determine longevity, mating, and oviposition activity. The total number of F₁ progeny was determined by counting all emerged adults. Grain Damage Assessment To quantify grain damage, 25 g of sterilized whole wheat, barley, and maize were each infested with 50 neonate (1-2d) T. granarium larvae per replicate in clean, sterilized plastic jars (150 ml). The jars were incubated at 33 ± 2°C and 62 ± 2% RH for 35 days, corresponding to the larval feeding period. After exposure, grains were sieved through a 500 µm mesh to separate larvae, exuviae, and frass, then oven-dried at 60°C for 48 h to standardize moisture content and reweighed. Statistical Analyses Data on the biological parameters of T. granarium were subjected to one-way analysis of variance (ANOVA) to determine significant differences among treatment means at 0.05, followed by Tukey’s HSD test for post hoc comparisons. All statistical analyses were carried out using RStudio (RStudio, 2011). Results Significant variation in larval weight was recorded across the different food substrates (F 8,36 = 11.05, p < 0.001). Substrate type significantly influenced larval weight, with wheat flour supporting the greatest mean larval mass and barley flour the lowest. (Fig. 1 .). Variation in pupal weight among larvae reared on different food substrates was statistically insignificant (F 8,36 = 0.69, p > 0.05), indicating that diet type had no measurable effect on pupal mass (Fig. 1 .). Significant differences in larval duration were observed among the tested food substrates. (F 8,36 = 14.27, p < 0.0001). Larvae reared on cracked wheat exhibited the shortest developmental duration, whereas those on barley flour took the longest to reach pupation (Fig. 2 ). The observed differences suggest that diet type substantially influences the growth rate of T. granarium larvae. The pupal period of T. granarium differed significantly among the tested food substrates (F 8,36 = 2.57, p > 0.024). Substrate type significantly affected pupal development, resulting in the shortest duration on wheat flour and the longest on whole maize. (Fig. 2 .). Similarly, the percentage of larvae successfully forming pupae varied significantly across diets (F 8,36 = 47.410, p < 0.001), with the highest pupation rate observed on cracked wheat and the lowest on cracked barley (Fig. 3 ). These findings indicate that both the duration of the pupal stage and the efficiency of pupal formation in T. granarium are influenced by the type of food substrate available during larval development. Adult emergence of T. granarium varied significantly among the tested food substrates (F 8,36 = 11.42, p < 0.001), (Fig. 3 ). The highest emergence rate was recorded from larvae reared on wheat flour, while the lowest was from those reared on barley flour. Similarly, adult longevity differed significantly across diets (F 8,36 = 18.47, p < 0.001) with beetles from wheat cracked surviving the longest (44.6 d) and those from barley flour the shortest (24.9 d) (Fig. 4 ). These results suggest that the nutritional and physical characteristics of the larval diet not only affect the proportion of individuals successfully reaching adulthood but also influence the lifespan of the emerged beetles. The female-biased sex ratio of T. granarium did not differ significantly among the food substrates (F₈,₃₆ = 1.01, p > 0.447). The highest bias (2.36) was recorded in adults reared on whole wheat, whereas the lowest (1.30) was observed in those reared on barley flour (Fig. 5 ). The number of F₁ progeny produced by T. granarium differed significantly among the tested food substrates (F 8,36 = 175.91, p < 0.0001). The highest mean progeny production was recorded on cracked wheat (92.20%), followed by whole wheat, while the lowest was on whole maize (Fig. 6 ). These differences in progeny output correspond with the observed patterns in adult emergence and longevity, suggesting that diets that support higher survival to adulthood and longer adult lifespan also tend to yield greater reproductive output. The results indicate that the physical and nutritional quality of the food substrate during larval development plays a critical role in determining the reproductive potential of T. granarium populations. Growth rates of T. granarium varied significantly among different food substrates (F₈,₃₆ = 17.23, p < 0.0001). The highest growth index (4.88) was recorded on cracked wheat, followed by wheat flour (4.75), whereas the lowest was observed on barley flour (3.15) (Fig. 7 ). Similarly, the percentage of food damage caused by T. granarium also differed significantly across substrates (F₈,₃₆ = 19.80, p < 0.0001). The maximum damage was recorded on cracked wheat (21.40%), while the minimum occurred on barley flour (12.00%) (Fig. 8 ). Hierarchical cluster analysis was performed on the F₁ progeny data of T. granarium reared on different food substrates to identify similarities in reproductive performance. The resulting dendrogram (Fig. 9 ) grouped the diets into distinct clusters based on the number of progeny produced. At the selected similarity threshold, two major clusters were performed. The first cluster included wheat, which exhibited relatively higher F₁ progeny numbers, indicating similar suitability for supporting beetle reproduction. The second cluster consisted of maize, characterized by significantly lower progeny output. This clear separation highlights the influence of substrate type on the reproductive potential of T. granarium . The dendrogram thus visually summarizes the relative reproductive fitness of T. granarium on the tested diets, reflecting their differential impact on population growth. Principal Component Analysis (PCA) was conducted to explore the variation in F₁ progeny production of T. granarium across the different food substrates. The first two principal components (PC1 and PC2) accounted for 34.9% and 33.4% of the total variation, respectively, together explaining the cumulative variance (Fig. 10 ). The PCA biplot revealed a clear separation among the tested diets based on their influence on F₁ progeny output. Diets positioned on the positive side of PC1, such as cracked wheat and whole wheat, were associated with higher F₁ progeny numbers, indicating these substrates provided more favorable conditions for reproduction. In contrast, whole maize, located on the negative side of PC1, correlated with lower progeny production. This ordination suggests that the nutritional and physical characteristics of the substrates significantly affect the reproductive potential of T. granarium . The clustering of diets in the PCA space highlights similarities in their suitability for supporting the pest’s population growth. Discussion Our results demonstrate that the type of larval diet significantly influenced all major fitness parameters of T. granarium , confirming and extending patterns reported in earlier studies. The biology and successful rearing of T. granarium depend heavily on the type of diet (Athanassiou et al. 2019 a). Wheat and wheat flour support the best development and are ideal for both pest management studies and laboratory maintenance. Understanding food preferences helps improve monitoring (Hodges & Rees 2012 ; Athanassiou et al. 2018 a), rearing efficiency (Naseri & Borzoui, 2016 , Burges, 1963 ), and control strategy design (Athanassiou, et al. 2018 b, Wakil et al. 2015 , Islam et al. 2010 ). The present study demonstrates that food substrate type exerts a marked influence on the development, survival, and reproduction of T. granarium . Significant variation in larval weight among diets indicates that the nutritional composition and physical characteristics of the substrate play critical roles in larval growth. Larvae reared on cereals attained the greatest mean weight, which is in accordance with the findings of Naseri & Borzoui ( 2016 ) and Suleiman & Abdullahi ( 2014 ). Moreover, Borzoui & Naseri ( 2016 ) reported that protein- and lipid-rich diets support higher biomass accumulation in T. granarium . Conversely, the lowest larval weight recorded on legumes and oilseed aligns with the data that have been reported by El-Lakwah et al. ( 1993 ), suggesting that low nutritional value and/or reduced digestibility can constrain larval growth. Interestingly, pupal weight did not vary significantly among diets, implying that once larvae reach the pupal stage, body mass is less influenced by diet quality. However, the significant differences in larval and pupal periods recorded in this study support earlier observations by Burges ( 1963 ), El-Lakwah et al. ( 1993 ), Naseri & Borzoui ( 2016 ), and Borzoui & Naseri ( 2016 ) all showed that diet significantly alters the larval and pupal periods of T. granarium that substrate quality can accelerate or delay development. The shortest larval and pupal durations on whole may be attributed to its higher nutritional adequacy and narrower weight range, while the prolonged development on flour barley and whole maize suggests poor nutritional suitability and increased energy expenditure during feeding. The proportion of larvae that were successfully pupated and the subsequent adult emergence rates also varied significantly among diets. The present study demonstrated that food substrates did not significantly influence the sex ratio of T. granarium . Although female-biased sex ratios were observed across all diets, statistical analysis revealed no significant differences among substrates. This indicates that sex allocation in T. granarium may be relatively stable and less dependent on nutritional quality, in contrast to other biological traits such as development time, fecundity, or survival, which are often strongly diet-dependent (Burges, 1963 ; Hagstrum & Subramanyam, 2009 ). The slight variation observed, with the highest female bias in whole wheat and the lowest in barley flour, may suggest that nutrient-rich substrates can enhance female emergence to some extent. Similar trends have been reported in other stored-product beetles, where higher-quality diets supported relatively more females, potentially reflecting adaptive strategies for maximizing reproductive output under favorable nutritional conditions (Athanassiou & Arthur, 2018). However, the lack of significant differences in the present study implies that T. granarium maintains a balanced reproductive strategy regardless of diet, possibly due to its adaptation as a primary pest of stored products. From a management perspective, these findings suggest that altering diet type alone may not strongly affect population sex structure. Since females are the primary contributors to population growth through oviposition, control efforts should focus on reducing overall survival and reproductive success rather than relying on potential shifts in sex ratio. The close correspondence between F₁ progeny production, adult emergence, and longevity highlights the fundamental influence of larval diet quality on reproductive capacity. Similar links between enhanced survival, prolonged adult lifespan, and increased fecundity have been documented previously (Borzoui & Naseri, 2016 ). In contrast, the diminished progeny production on cracked maize observed here concurs with earlier findings (El-Lakwah et al., 1993 ; Athanassiou et al., 2016 ) and may be explained by suboptimal nutrient assimilation during larval development. Our results demonstrate that T. granarium exhibits significantly higher growth indices and food damage potential when reared on cracked wheat, compared to wheat flour and barley flour, which was the least favorable substrate. An earlier work by Naseri and Borzoui ( 2016 ) on various wheat cultivars revealed that larval weight gain, relative growth rate, and digestive enzyme activity were highest on certain cultivars (e.g., ‘Arg’) and lowest on others like 'Parsi' and 'Morvarid', which were considered poor for beetle development. This underscores that substrate quality—whether due to cultivar-specific nutritional profiles or physical structure—plays a critical role in T. granarium ’s growth. Comparative evaluations of grain genotype susceptibility underline the critical role of inherent grain characteristics. Yousuf et al. ( 2025 ) reported that the wheat variety Arooj-2022 sustained significantly higher post-storage damage (up to 17.70% after 90 days) than Akbar-2019 (as low as 4.37%), attributing this divergence to varietal differences in both seed moisture content and inherent resistance traits. Though our study compared different substrate types rather than genotypes, the parallel is clear—substrate physical and nutritional properties significantly affect both beetle growth and damage inflicted. Earlier studies have shown that barley can strongly favor T. granarium population growth, supporting shorter generation times, higher fecundity, and increased intrinsic rates of increase relative to other cereals (Karagianni et al., 2019 ). Conversely, barley flour in the present study produced the lowest growth index and damage, indicating that substrate physical form—flour versus intact grain—substantially affects larval accessibility and resource utilization and may underlie the contrasting outcomes. The hierarchical cluster analysis and PCA both revealed distinct groupings of diets based on reproductive performance. Diets that clustered together exhibited similar F₁ progeny outputs, reinforcing the concept that diet quality consistently influences reproductive fitness. Such multivariate approaches have also been applied by Sinha et al. ( 1969 ) to identify diet groupings for stored-product insects, highlighting their utility in pest ecology research. Overall, the findings of this study underscore the importance of food substrate quality in shaping the population dynamics of T. granarium . By identifying diets that support rapid development, high survival, and elevated reproductive output, these results have practical implications for pest management strategies. For example, in storage facilities, restricting access to nutrient-rich commodities or incorporating less suitable substrates could help suppress T. granarium populations. Moreover, the observed congruence between our results and those of previous studies strengthens the evidence that diet composition is a key determinant of T. granarium biology and can be leveraged in integrated pest management programs. The strong concordance between our data and previous studies confirms that grain types high in starch and protein (e.g. wheat, rye) favor T. granarium development and reproduction, while oil-bearing seeds and legumes (e.g. walnut, almond) are comparatively unsuitable hosts. These insights are highly relevant for storage practices: limiting access to favorable substrates and targeting control efforts in high-risk commodities could help suppress potential population build-up. Conclusions Overall, our results underscore the central role of food substrate quality—particularly macronutrient composition and digestibility—in regulating life-history traits and population growth potential of T. granarium . This interpretation aligns with previous reviews documenting the species’ exceptional adaptability to hot, dry conditions and its ability to rapidly exploit nutritionally suitable substrates, thereby exacerbating infestation severity (Athanassiou et al. 2019 a). By confirming earlier observations and expanding them through multivariate clustering approaches, the present work enhances the biological rationale for substrate-focused, integrated pest management strategies in stored-product systems. Declarations Authors contribution Tanushree Barman: Data curation, Formal analysis, Investigation,. Shakila Khatun Bristy: Formal analysis, Investigation, Md. Saiful Islam: Methodology, Formal analysis; Paraskevi Agrafioti: Conceptualization, Writing. Christos G. Athanassiou: Conceptualization, Writing - review & editing final draft, Md. Mahbub Hasan: Conceptualization, Methodology, Statistical analysis, writing Original draft. Competing interest The authors declare no competing interests. Ethics approval This article does not contain any studies with human participants or animals performed by any of the authors. Funding This research did not receive funding from any organization. Acknowledgement The authors are grateful to the Department of Zoology, University of Rajshahi, for providing laboratory facilities and support. Data availability Data is provided within the manuscript and raw data will be made available on request. References Agarwal N, Kalra VK, Jalali SK (1988) Influence of food media on growth and fecundity of Trogoderma granarium (Everts). Indian J Entomol 50:275–281 Al-Jboory SA, Al-Rawy MA (2021) Influence of commodity on the biology of Trogoderma granarium Everts (Coleoptera: Dermestidae): development, growth, and survival. J Stored Prod Res 94:101881. https://doi.org/10.1016/j.jspr.2021.101881 Arthur FH, Domingue MJ, Scheff DS, Myers SW (2019) Bioassays and methodologies for insecticide tests with larvae of Trogoderma granarium (Everts), the khapra beetle. Insects 10:145. https://doi.org/10.3390/insects10050145 Athanassiou CG, Phillips TW, Wakil W (2019) Biology and control of the khapra beetle, Trogoderma granarium , a major quarantine threat to global food security. Annu Rev Entomol 64:131–148. https://doi.org/10.1146/annurev-ento-011118-111804 Athanassiou CG, Arthur FH, Campbell JF (2018) Biological and ecological traits of the khapra beetle, Trogoderma granarium , a global stored product pest. Annu Rev Entomol 63:131–148. https://doi.org/10.1146/annurev-ento-020117-043405 Athanassiou CG, Arthur FH, Kavallieratos NG (2018) Monitoring stored-product insect pests: traps and attractants. Insects 9:82. https://doi.org/10.3390/insects9030082 Athanassiou CG, Kavallieratos NG, Andris NS (2010) Evaluation of various commodities for the development of the yellow mealworm, Tenebrio molitor (Coleoptera: Tenebrionidae). J Stored Prod Res 46:245–249. https://doi.org/10.1016/j.jspr.2010.05.003 Athanassiou CG, Kavallieratos NG, Boukouvala MC (2016) Population growth of the khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae) on different commodities. J Stored Prod Res 69:72–77. https://doi.org/10.1016/j.jspr.2016.07.005 Bhattacharya AK, Pant NC (1969) The effect of different food media on the rate of development of Trogoderma granarium Everts (Coleoptera: Dermestidae). J Stored Prod Res 5:199–204. https://doi.org/10.1016/0022-474X(69)90031-5 Borzoui E, Naseri B (2016) Effects of dietary protein and carbohydrate balance on growth and reproduction of Trogoderma granarium . Bull Entomol Res 106:444–452. https://doi.org/10.1017/S0007485316000122 Borzoui E, Athanassiou CG, Kavallieratos NG, et al. (2015) Different diets affecting biology and digestive physiology of Trogoderma granarium . J Stored Prod Res 62:25–33. https://doi.org/10.1016/j.jspr.2015.04.001 Burges HD (1962) The developmental rate of Trogoderma granarium Everts (Coleoptera: Dermestidae) in relation to temperature. Bull Entomol Res 53:119–130. https://doi.org/10.1017/S0007485300048172 Burges HD (1963) Studies on the dermestid beetle Trogoderma granarium Everts. VI. Factors affecting larval growth and survival on cereal grains. Bull Entomol Res 54:751–765. https://doi.org/10.1017/S0007485300048834 Cox PD, Simms SG (1978) The fecundity and development of Trogoderma granarium Everts (Coleoptera: Dermestidae) in relation to temperature. J Stored Prod Res 14:107–118. https://doi.org/10.1016/0022-474X(78)90027-1 El-Lakwah FA, Mohamed HA, El-Sayed YA (1993) The effect of different diets on the biology and development of the khapra beetle, Trogoderma granarium Everts. J Appl Entomol 115:179–185. https://doi.org/10.1111/j.1439-0418.1993.tb00376.x EPPO (2013) Insect meal as renewable source of food for animal feeding: a review. EPPO Bull 43:293–298. https://doi.org/10.1111/epp.12040 Gaur RK, Rana SKS, et al. (2022) Developmental response of Trogoderma granarium Everts to durable wheat cultivars. Int J Trop Insect Sci 42:3525–3535. https://doi.org/10.1007/s42690-022-00853-z Goyal LN, Gaur RK, et al. (2024) Susceptibility of stored pearl millet products to khapra beetle infestation. J Food Prot 87:100311. https://doi.org/10.1016/j.jfp.2024.100311 Hagstrum DW, Subramanyam B (2009) Stored-product insect resource. AACC International, St. Paul Hodges RJ, Rees DP (2012) Detection methods for Trogoderma granarium Everts (Coleoptera: Dermestidae): a quarantine pest in stored products. J Stored Prod Res 50:47–61. https://doi.org/10.1016/j.jspr.2012.04.004 Islam MS, Hasan MM, Lei C, Mucha-Pelzer T, Rahman MM, Mewis I (2010) Insecticidal activity of plant oils against Trogoderma granarium Everts (Coleoptera: Dermestidae). J Stored Prod Res 46:255–260. https://doi.org/10.1016/j.jspr.2010.05.002 Karagianni E, Gasco L, Fountoulaki E (2019) Animals fed insect-based diets: state-of-the-art on digestibility, performance, and product quality. Animals 9:170. https://doi.org/10.3390/ani9040170 Kavallieratos NG, Athanassiou CG, Arthur FH (2016) Residual efficacy of insecticides on different surfaces against Trogoderma granarium Everts (Coleoptera: Dermestidae). J Econ Entomol 109:1957–1964. https://doi.org/10.1093/jee/tow140 Kavallieratos NG, Nika EP, Skourti A, Ntalli N, Boukouvala MC, Ntalaka CT, Maggi F, Rakotosaona R, Spinozzi E (2022) Essential oil-based nanostructured pesticides: design and performance for control of Trogoderma granarium (Coleoptera: Dermestidae) adults. Ind Crops Prod 188:115541. https://doi.org/10.1016/j.indcrop.2022.115541 Kavallieratos D, Rologas M, et al. (2024) Development and population growth of khapra beetle Trogoderma granarium (Coleoptera: Dermestidae) on different commercial wheat products. J Econ Entomol 117:1451–1459. https://doi.org/10.1093/jee/toae101 Naseri B, Borzoui E (2016) Life cycle and digestive physiology of Trogoderma granarium (Coleoptera: Dermestidae) on different wheat cultivars. Ann Entomol Soc Am 109:905–911. https://doi.org/10.1093/aesa/saw048 Naseri A, Borzoui G, Naseri B (2023) Comparative development and population growth of Trogoderma granarium Everts (Coleoptera: Dermestidae) on different wheat cultivars and their milling fractions. J Stored Prod Res 103:102200. https://doi.org/10.1016/j.jspr.2023.102200 Nayak MK, Collins PJ, et al. (2022) Comparative population growth of the khapra beetle, Trogoderma granarium (Coleoptera: Dermestidae), on different commodities. J Econ Entomol 115:1030–1039. https://doi.org/10.1093/jee/toac058 R Core Team (2020) R: a language and environment for statistical computing. R Foundation for Statistical Computing, Vienna Rajput SA, Khanzada MS, Abro GH, Khanzada SR, Syed TS, Su W (2015) Comparative population growth and losses caused by beetle Trogoderma granarium (Everts) to selected past and present wheat genotypes. J (Incomplete citation; please verify full title and journal) Rao RSV, Raju MVLN, Reddy MR, Panda AK (2004) Replacement of yellow maize with pearl millet (Pennisetum typhoides), foxtail millet (Setaria italica), or finger millet (Eleusine coracana) in broiler chicken diets containing supplemental enzymes. Asian-Australas J Anim Sci 17:836–842. https://doi.org/10.5713/ajas.2004.836 Shah PA, Bowers K (2025) A meta-analysis of the global risk thresholds for Trogoderma granarium establishment under climate change scenarios. Pest Manag Sci (In press; DOI not yet available) Sinha RN, Wallace HAH, Chebib FS (1969) Principal component analysis of interrelations among fungi, mites, and insects in grain bulk ecosystems. Ecology 50:536–547. https://doi.org/10.2307/1933911 Suleiman M, Abdullahi G (2014) Nutritional composition of some cereals and legumes and their effects on development of Trogoderma granarium . J Stored Prod Res 59:87–93. https://doi.org/10.1016/j.jspr.2014.07.001 Viljoen JH (1990) The occurrence of Trogoderma (Coleoptera: Dermestidae) and related species in southern Africa with special reference to T. granarium and its potential to become established. J Stored Prod Res 26:43–51. https://doi.org/10.1016/0022-474X(90)90010-V Wakil W, Ghazanfar MU, Lord JC (2015) Entomopathogenic fungi for the control of the khapra beetle, Trogoderma granarium . Biol Control 90:1–10. https://doi.org/10.1016/j.biocontrol.2015.05.015 Wilches DM, Laird RA, Floate KD, Fields PG (2016) A review of diapause and tolerance to extreme temperatures in dermestids (Coleoptera). J Stored Prod Res 68:50–62. https://doi.org/10.1016/j.jspr.2016.04.001 Wilches DM, Laird RA, Floate KD, Fields PG (2019) Control of Trogoderma granarium (Coleoptera: Dermestidae) using high temperatures. J Econ Entomol 112:963–968. https://doi.org/10.1093/jee/toy413 Yadav SK, Srivastava C (2017) Effect of temperature and food on the biology of khapra beetle, Trogoderma granarium Everts. J Entomol Zool Stud 5:1015–1019 Yousuf HMB, Yasin M, Khan MA, Abbasi A, Arshad M, Aqueel MA, Ul Haq I, Alsakkaf WAA, Mackled MI, Rebouh NY, et al. (2025) Assessment of different conventional and biofortified wheat genotypes based on biology and damage pattern of Rhyzopertha dominica and Trogoderma granarium . Insects 16:66. https://doi.org/10.3390/insects16010066 Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8562917","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":575408643,"identity":"80428bde-11bd-42fb-900b-7b6bf4a228a3","order_by":0,"name":"Tanushree Barman","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Tanushree","middleName":"","lastName":"Barman","suffix":""},{"id":575408644,"identity":"20180159-741b-420a-8838-8c8458040fab","order_by":1,"name":"Bannya Ghosh","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Bannya","middleName":"","lastName":"Ghosh","suffix":""},{"id":575408645,"identity":"bceed0fc-15fd-41a0-b9d3-ede0ff27f26e","order_by":2,"name":"Shakila Khatun Bristy","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Shakila","middleName":"Khatun","lastName":"Bristy","suffix":""},{"id":575408646,"identity":"7aa9a19d-00e7-44da-8d78-bdf0586f05c6","order_by":3,"name":"Md. Saiful Islam","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Md.","middleName":"Saiful","lastName":"Islam","suffix":""},{"id":575408647,"identity":"992640d5-be96-4bdb-b1cf-926e9cec207a","order_by":4,"name":"Paraskevi Agrafioti","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Paraskevi","middleName":"","lastName":"Agrafioti","suffix":""},{"id":575408648,"identity":"586aa652-c8dd-438a-b30b-7ffebbc9c832","order_by":5,"name":"Christos G. Athanassiou","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Christos","middleName":"G.","lastName":"Athanassiou","suffix":""},{"id":575408649,"identity":"81f5122f-dc88-4305-8ce1-b6ea16815b2f","order_by":6,"name":"Md.. Mahbub Hasan","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAqklEQVRIiWNgGAWjYFACHjYGBjYbBgYJErWkka7lMAladKedPfbwS9n5xP7ZzQcfMNTYRBPUYnY7L91Y5tztxBl3jiUbMBxLy20grCXHTFqy7XZiw40cMwnGhsNEazmXOJ8kLZIf2w4kbiBFi7kxw7lk44030pINEoj1y8MfZXay824kH3zwocaGsBYQYOZhYHAEq0wgRjkIMP5gYLAnVvEoGAWjYBSMQAAAvHNDKFBnissAAAAASUVORK5CYII=","orcid":"","institution":"University of Rajshahi","correspondingAuthor":true,"prefix":"","firstName":"Md..","middleName":"Mahbub","lastName":"Hasan","suffix":""}],"badges":[],"createdAt":"2026-01-09 16:31:24","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8562917/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8562917/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":100698557,"identity":"9f8bee72-b3de-4146-b379-4666c90dc70e","added_by":"auto","created_at":"2026-01-20 15:27:52","extension":"xml","order_by":1,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":8668,"visible":true,"origin":"","legend":"","description":"","filename":"jpdpJPDPD2600053.xml","url":"https://assets-eu.researchsquare.com/files/rs-8562917/v1/4597d29152fa2fdc1a1c4e0e.xml"},{"id":100698579,"identity":"76202b84-8111-4eaf-9abd-7252ded5bf8f","added_by":"auto","created_at":"2026-01-20 15:28:14","extension":"xml","order_by":2,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":941,"visible":true,"origin":"","legend":"","description":"","filename":"JPDPD260005324779.go.xml","url":"https://assets-eu.researchsquare.com/files/rs-8562917/v1/e5b0db576bb22f211259d3d0.xml"},{"id":100698535,"identity":"7a7f2b50-5376-43f5-836e-c0f5b0c8ab7c","added_by":"auto","created_at":"2026-01-20 15:27:33","extension":"xml","order_by":3,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":867,"visible":true,"origin":"","legend":"","description":"","filename":"JPDPD2600053Import.xml","url":"https://assets-eu.researchsquare.com/files/rs-8562917/v1/f425dfbd56ac582741dc5b41.xml"},{"id":100698596,"identity":"a6e02a3e-22ee-4998-8ecd-8ab24ceb386b","added_by":"auto","created_at":"2026-01-20 15:28:23","extension":"xml","order_by":4,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":106779,"visible":true,"origin":"","legend":"","description":"","filename":"JPDPD26000530enriched.xml","url":"https://assets-eu.researchsquare.com/files/rs-8562917/v1/7735e90f47a4ec603d24d96c.xml"},{"id":100698564,"identity":"0ddd1c4e-f9cb-483a-9623-5476917d6a11","added_by":"auto","created_at":"2026-01-20 15:27:57","extension":"png","order_by":15,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":12170,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-8562917/v1/5f2abab18fc99da337af20da.png"},{"id":100699013,"identity":"d30b8cc3-2160-42b2-9f83-5fb9faba3e98","added_by":"auto","created_at":"2026-01-20 15:31:56","extension":"png","order_by":16,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":21131,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage10.png","url":"https://assets-eu.researchsquare.com/files/rs-8562917/v1/975ea8cd6082817cd1578d62.png"},{"id":100698933,"identity":"dbb610b9-994a-4a9d-a806-351f9be5c004","added_by":"auto","created_at":"2026-01-20 15:31:19","extension":"png","order_by":17,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":43034,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-8562917/v1/533a814b99f5628bee632a41.png"},{"id":100698580,"identity":"7d63ddd1-5b00-44d6-8411-705e949ad3ce","added_by":"auto","created_at":"2026-01-20 15:28:14","extension":"png","order_by":18,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":15620,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-8562917/v1/11f1990ad0e1a4b73149d39f.png"},{"id":100698578,"identity":"0d129c39-88ba-49ad-8661-d03d5c7ab70f","added_by":"auto","created_at":"2026-01-20 15:28:13","extension":"png","order_by":19,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":11831,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-8562917/v1/7530cb61025c4478278a9c69.png"},{"id":100698484,"identity":"855e8d37-174c-4c24-bc2c-85f409a690f4","added_by":"auto","created_at":"2026-01-20 15:27:24","extension":"png","order_by":20,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":12096,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-8562917/v1/372b830a599b468527e88a73.png"},{"id":100698741,"identity":"29021927-818f-41ce-937c-52e5dc252dca","added_by":"auto","created_at":"2026-01-20 15:29:05","extension":"png","order_by":21,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":9917,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-8562917/v1/8f96581438eed0f9128163e1.png"},{"id":100698595,"identity":"232c1184-67e0-4f32-a731-69ce78415d5c","added_by":"auto","created_at":"2026-01-20 15:28:22","extension":"png","order_by":22,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":11071,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-8562917/v1/c9741c4e8fac134c14f20d5f.png"},{"id":100698562,"identity":"ebac6eee-60e3-48e5-8ecf-0b9c1d343bb9","added_by":"auto","created_at":"2026-01-20 15:27:54","extension":"png","order_by":23,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":10909,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage8.png","url":"https://assets-eu.researchsquare.com/files/rs-8562917/v1/f2c9358e840b855c2d0ecc5c.png"},{"id":100698576,"identity":"3d3b3762-9723-42d8-980c-6693d898e542","added_by":"auto","created_at":"2026-01-20 15:28:12","extension":"png","order_by":24,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":9466,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage9.png","url":"https://assets-eu.researchsquare.com/files/rs-8562917/v1/4c55f46c9f542dac41ea39bb.png"},{"id":100698921,"identity":"384c01c3-0eac-4b5c-917d-29384e674c9d","added_by":"auto","created_at":"2026-01-20 15:31:05","extension":"xml","order_by":25,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":102608,"visible":true,"origin":"","legend":"","description":"","filename":"JPDPD26000530structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-8562917/v1/fc4faf1f0baf5278f1c9b42e.xml"},{"id":100698568,"identity":"ca191594-ba67-4087-8585-8fa1f257882d","added_by":"auto","created_at":"2026-01-20 15:28:07","extension":"html","order_by":26,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":116479,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-8562917/v1/283fada67b070fc5b82094a8.html"},{"id":100698987,"identity":"e15b4e3a-ea73-4a22-8281-14402dc73162","added_by":"auto","created_at":"2026-01-20 15:31:32","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":20208,"visible":true,"origin":"","legend":"\u003cp\u003eMean larval and pupal weight (mg ± SE) of \u003cem\u003eTrogoderma granarium\u003c/em\u003e reared on different food substrates under laboratory conditions. (Different letters with the stage indicate significant differences (\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.05, Tukey’s HSD).\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-8562917/v1/ea1ad41c6cb3f8f24b2d212a.png"},{"id":100698919,"identity":"f47190a3-1569-4085-bbce-d73f3e42edac","added_by":"auto","created_at":"2026-01-20 15:31:04","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":222187,"visible":true,"origin":"","legend":"\u003cp\u003eMean larval and pupal periods (days ± SE) of \u003cem\u003eTrogoderma granarium\u003c/em\u003e reared on different food substrates under laboratory conditions. (Different letters within each stage indicate significant differences (\u003cem\u003ep\u003c/em\u003e\u0026lt; 0.05, Tukey’s HSD).\u003c/p\u003e","description":"","filename":"floatimage2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8562917/v1/f6178721945cb3ee64789312.jpeg"},{"id":100698536,"identity":"1b26b617-9fdc-45b4-a755-5485e5c5172d","added_by":"auto","created_at":"2026-01-20 15:27:36","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":25821,"visible":true,"origin":"","legend":"\u003cp\u003eMean pupal formation and adult emergence (% ± SE) of \u003cem\u003eTrogoderma granarium\u003c/em\u003ereared on different food substrates under laboratory conditions. (Different letters within each stage indicate significant differences (\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.05, Tukey’s HSD).\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-8562917/v1/366bd7e52687371871f18eab.png"},{"id":100698935,"identity":"d34286c1-b3a0-4ce7-80ec-038579b6e59b","added_by":"auto","created_at":"2026-01-20 15:31:21","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":19356,"visible":true,"origin":"","legend":"\u003cp\u003eMean adult longevity (days ± SE) of \u003cem\u003eTrogoderma granarium\u003c/em\u003e reared on different food substrates. Different letters above bars indicate significant differences (\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.05, Tukey’s HSD).\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-8562917/v1/81b2e7e68045d579a1c9d7c7.png"},{"id":100698566,"identity":"28d64dd2-5320-4f13-b92e-a4ea3322e2fc","added_by":"auto","created_at":"2026-01-20 15:27:58","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":19720,"visible":true,"origin":"","legend":"\u003cp\u003eMean female proportion ( ± SE) in \u003cem\u003eTrogoderma granarium\u003c/em\u003e reared on different food substrates. Different letters above bars indicate significant differences (\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.05, Tukey’s HSD).\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-8562917/v1/2df44120a775996da35dbf35.png"},{"id":100699017,"identity":"daaf61e2-7207-41f5-a5dc-80a48e4abaef","added_by":"auto","created_at":"2026-01-20 15:31:58","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":17582,"visible":true,"origin":"","legend":"\u003cp\u003eMean F\u003csub\u003e1\u003c/sub\u003e adult progeny (% ± SE) of \u003cem\u003eTrogoderma granarium\u003c/em\u003e reared on different food substrates. Different letters above bars indicate significant differences (\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.05, Tukey’s HSD).\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-8562917/v1/b6d1c47969f2072139ee7611.png"},{"id":100698911,"identity":"b93d5545-c597-4ada-8b57-aaa032a69ea5","added_by":"auto","created_at":"2026-01-20 15:30:57","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":17570,"visible":true,"origin":"","legend":"\u003cp\u003eMean growth indices (± SE) of \u003cem\u003eTrogoderma granarium\u003c/em\u003e reared on different food substrates. Different letters above bars indicate significant differences (\u003cem\u003ep\u003c/em\u003e\u0026lt; 0.05, Tukey’s HSD).\u003c/p\u003e","description":"","filename":"floatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-8562917/v1/540d77e8a918c579a1718a5c.png"},{"id":100699021,"identity":"c526dcda-59e4-4d16-8f60-ebe59f32cdbb","added_by":"auto","created_at":"2026-01-20 15:32:04","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":18919,"visible":true,"origin":"","legend":"\u003cp\u003eMean percent damage (± SE) of \u003cem\u003eTrogoderma granarium\u003c/em\u003e reared on different food substrates. Different letters above bars indicate significant differences (\u003cem\u003ep\u003c/em\u003e\u0026lt; 0.05, Tukey’s HSD).\u003c/p\u003e","description":"","filename":"floatimage8.png","url":"https://assets-eu.researchsquare.com/files/rs-8562917/v1/e429fb7d8dae43301ace9212.png"},{"id":100699015,"identity":"ef144a5b-bb3c-4781-8b78-28c15c2bcada","added_by":"auto","created_at":"2026-01-20 15:31:58","extension":"jpeg","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":43313,"visible":true,"origin":"","legend":"\u003cp\u003eDendrogram showing hierarchical clustering of food substrates based on F₁progeny counts of \u003cem\u003eTrogoderma granarium\u003c/em\u003e. Similar diets cluster together, reflecting comparable reproductive output.\u003c/p\u003e","description":"","filename":"floatimage9.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8562917/v1/0e237d5e29a99ba1b3472bd2.jpeg"},{"id":100698546,"identity":"cfd6e7e3-1ebf-4f10-a452-3f8fb58e3a7e","added_by":"auto","created_at":"2026-01-20 15:27:46","extension":"jpeg","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":65480,"visible":true,"origin":"","legend":"\u003cp\u003ePCA biplot showing the distribution of different food substrates based on F₁progeny production of \u003cem\u003eTrogoderma granarium\u003c/em\u003e. Arrows indicate the direction and strength of variables contributing to variance. Diets closer together exhibit similar effects on progeny output.\u003c/p\u003e","description":"","filename":"floatimage10.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8562917/v1/28ea76407d30d90325f7b978.jpeg"},{"id":104400739,"identity":"8d3054cf-dd53-4f04-89b8-d5d51d1c4d97","added_by":"auto","created_at":"2026-03-11 12:10:52","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1060011,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8562917/v1/f731a891-385a-499e-b4a5-cf5e94480c85.pdf"}],"financialInterests":"","formattedTitle":"Growth and Development of the Khapra Beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae), on Different Food Substrates","fulltext":[{"header":"Introduction","content":"\u003cp\u003eThe khapra beetle, \u003cem\u003eTrogoderma granarium\u003c/em\u003e Everts (Coleoptera: Dermestidae), is regarded as one of the most destructive pests of stored agricultural commodities (Arthur et al. \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Athanassiou et al. \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2019\u003c/span\u003ea; Ahmed, et al. 2025). Native to South Asia, it has spread to many parts of Africa, the Middle East, and other warmer regions, where it thrives under arid conditions (Athanassiou et al. \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2019\u003c/span\u003ea, Kavallieratos et al. \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2016\u003c/span\u003e; Shah and Brower, 2025). Its inclusion in the list of \u0026ldquo;100 of the World\u0026rsquo;s Worst Invasive Alien Species\u0026rdquo; and as a major A2 quarantine pest by the European and Mediterranean Plant Protection Organization (EPPO) underscores its global economic significance (Viljoen, \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e1990\u003c/span\u003e, EPPO, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2013\u003c/span\u003e; Wilches et al. \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). Infestations can result in weight losses of stored grain up to 70% under severe conditions, coupled with qualitative deterioration due to contamination with larval skins, frass, and urticating hairs, which render the product unfit for human or animal consumption (Wilches et al, \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2016\u003c/span\u003e; Athanassiou etal. \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2019\u003c/span\u003eb).\u003c/p\u003e \u003cp\u003eOne of the remarkable features of \u003cem\u003eT. granarium\u003c/em\u003e is its high adaptability to a variety of food sources and storage environments (Cox and Simms, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e1978\u003c/span\u003e; Athanassiou et al. \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2019\u003c/span\u003ea). The larvae can survive without food for extended periods\u0026mdash;up to several years in diapause\u0026mdash;and tolerate wide temperature fluctuations, making eradication extremely challenging (Burges, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e1962\u003c/span\u003e, Wilches et al. \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). The pest attacks a broad range of stored products, including wheat, rice, maize, barley, sorghum, pulses, oilseeds, and various processed foods. However, the development rate, survival, and fecundity of the beetle vary considerably depending on the type and physical condition of the food substrate (Athanassiou et al. \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2019\u003c/span\u003ea, El Halafawy, N.A., et al. 2025).\u003c/p\u003e \u003cp\u003eThe physical form of the commodity, such as whether it is whole grain, cracked kernels, or finely milled flour, plays a crucial role in determining its suitability for \u003cem\u003eT. granarium\u003c/em\u003e growth and reproduction (Borzoui et al. \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2015\u003c/span\u003e, Yadav and Srivastava, \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). Whole grains offer a harder, intact seed coat that can restrict larval penetration, whereas cracked grains provide more accessible endosperm and germ tissues (Athanassiou et al. \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2010\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). Finely ground grain products or different types of flour may offer a higher surface area and easier access to nutrients but can also present physical constraints such as compaction, reduced aeration, or moisture absorption differences (Rao et al. \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2004\u003c/span\u003e). Nutritional composition, particle size, and structural integrity of the substrate thus interact to influence the pest\u0026rsquo;s developmental biology (Agarwal et al. \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1988\u003c/span\u003e)\u003c/p\u003e \u003cp\u003eThe growth and development of \u003cem\u003eT. granarium\u003c/em\u003e are strongly influenced by the type and condition of the food substrate (Athanassiou et al. \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2016\u003c/span\u003e; Bhattacharya and Pant, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e1969\u003c/span\u003e). Different grain forms\u0026mdash;whole cereals, cracked grains, and milled products\u0026mdash;vary in their nutritional composition, surface area, and accessibility to feeding stages, potentially affecting larval development, pupation, and adult emergence (Rao et al. \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2004\u003c/span\u003e; Rajput et al. \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). Understanding the developmental biology of this pest under various food forms is essential for predicting population dynamics and designing effective management strategies.\u003c/p\u003e \u003cp\u003eAlthough previous research has examined the biology of \u003cem\u003eT. granarium\u003c/em\u003e on selected commodities, there is limited comprehensive information on its comparative performance across different physical forms of the same cereal commodity under controlled conditions (Naseri et al. \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2023\u003c/span\u003e, Al-Jboory and Al-Rawy \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2021\u003c/span\u003e, Gaur et al. \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2022\u003c/span\u003e, Goyal, et al. \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). Understanding these differences is important for several reasons: (a) it aids in predicting the risk of population build-up in mixed storage systems where whole grains, partially processed products, and flours coexist (Kavallieratos et al. \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2024\u003c/span\u003e), (b) it supports the development of more targeted monitoring and management strategies, including substrate-specific preventive measures (Kavallieratos et al. \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2022\u003c/span\u003e), (c) it contributes to more accurate pest risk assessments for trade and quarantine purposes (Nayak and Collins, 2022).\u003c/p\u003e \u003cp\u003eThe present study was conducted to investigate the growth and development of \u003cem\u003eT. granarium\u003c/em\u003e on three different forms of cereal substrates\u0026mdash;whole grains, cracked grain fractions, and grain flour\u0026mdash;under standardized laboratory conditions. Key developmental parameters such as larval duration, pupal period, adult emergence, and survival rates were recorded and compared. The results are expected to provide valuable insights into the substrate preferences and performance of \u003cem\u003eT. granarium\u003c/em\u003e, thereby helping to improve storage management practices and pest control interventions in both domestic and commercial grain storage systems.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eInsect Collection and Culture Establishment\u003c/h2\u003e \u003cp\u003eLarvae and adults of the khapra beetle, \u003cem\u003eT. granarium\u003c/em\u003e, were collected from infested grain stocks in local markets across Rajshahi Metropolitan City, Bangladesh. The collected specimens were transported to the Entomology Laboratory, Department of Zoology, University of Rajshahi, and reared for two generations under controlled environmental conditions (32\u0026ndash;35\u0026deg;C, 62\u0026ndash;65% RH, and a 12:12 h light: dark photoperiod) in decontaminated 1 L plastic containers containing whole wheat grains. This pre-experimental rearing ensured genetic uniformity and adaptation to laboratory conditions.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003ePreparation of diets\u003c/h3\u003e\n\u003cp\u003eThree grain type, such as wheat (\u003cem\u003eTriticum aestivum\u003c/em\u003e L.), barley (\u003cem\u003eHordeum vulgare\u003c/em\u003e L.), and maize (\u003cem\u003eZea mays\u003c/em\u003e L.) were purchased from regional markets and confirmed to be free from insect infestation. Each grain type was prepared in three physical forms: (i) whole grains (intact kernels), (ii) cracked grains (mechanically fractured kernels, 2\u0026ndash;4 mm particle size using a roller mill), and (iii) powdered grains (finely ground material passed through a 500 \u0026micro;m sieve (Philips HL7756 grinder).\u003c/p\u003e \u003cp\u003eAll grain types underwent a two-step sterilization process: refrigeration at -20\u0026deg;C for 48 h to suppress microbial activity, followed by acclimatization at 25\u0026thinsp;\u0026plusmn;\u0026thinsp;1\u0026deg;C for 24 h to stabilize moisture content. This resulted in nine diet treatments arranged in a 3 \u0026times; 3 factorial design (grain type \u0026times; physical form). Each treatment was replicated five times, yielding 45 experimental units.\u003c/p\u003e\n\u003ch3\u003eExperimentation\u003c/h3\u003e\n\u003cp\u003eClean, disinfected plastic jars (150 ml) were used for the bioassays. Each jar was filled with 25 g of one of the nine prepared diet types, with five replicates per treatment. Young larvae (2\u0026ndash;3 days old; average length 3.0 mm measured under a microscope) were individually handled, and 50 larvae were introduced into each jar. The jars were covered with gauze cloth secured with rubber bands and placed in an incubator set at 35\u0026deg;C and 62\u0026ndash;65% RH.\u003c/p\u003e \u003cp\u003eLarvae were monitored for 10\u0026ndash;12 days to record larval duration and weight. Pupae were subsequently observed for 4\u0026ndash;5 days to record pupal period, number, and weight. Adult beetles were sexed under a microscope, and relevant data were recorded. Five pairs of adults from each treatment were transferred to separate jars for F₁ progeny assessment. Adult emergence was monitored for 10\u0026ndash;11 days to determine longevity, mating, and oviposition activity. The total number of F₁ progeny was determined by counting all emerged adults.\u003c/p\u003e\n\u003ch3\u003eGrain Damage Assessment\u003c/h3\u003e\n\u003cp\u003eTo quantify grain damage, 25 g of sterilized whole wheat, barley, and maize were each infested with 50 neonate (1-2d) \u003cem\u003eT. granarium\u003c/em\u003e larvae per replicate in clean, sterilized plastic jars (150 ml). The jars were incubated at 33\u0026thinsp;\u0026plusmn;\u0026thinsp;2\u0026deg;C and 62\u0026thinsp;\u0026plusmn;\u0026thinsp;2% RH for 35 days, corresponding to the larval feeding period. After exposure, grains were sieved through a 500 \u0026micro;m mesh to separate larvae, exuviae, and frass, then oven-dried at 60\u0026deg;C for 48 h to standardize moisture content and reweighed.\u003c/p\u003e\n\u003ch3\u003eStatistical Analyses\u003c/h3\u003e\n\u003cp\u003eData on the biological parameters of \u003cem\u003eT. granarium\u003c/em\u003e were subjected to one-way analysis of variance (ANOVA) to determine significant differences among treatment means at 0.05, followed by Tukey\u0026rsquo;s HSD test for post hoc comparisons. All statistical analyses were carried out using RStudio (RStudio, 2011).\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eSignificant variation in larval weight was recorded across the different food substrates (F\u003csub\u003e\u003cem\u003e8,36\u003c/em\u003e\u003c/sub\u003e = 11.05, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Substrate type significantly influenced larval weight, with wheat flour supporting the greatest mean larval mass and barley flour the lowest. (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.). Variation in pupal weight among larvae reared on different food substrates was statistically insignificant (F\u003csub\u003e\u003cem\u003e8,36\u003c/em\u003e\u003c/sub\u003e = 0.69, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05), indicating that diet type had no measurable effect on pupal mass (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.). Significant differences in larval duration were observed among the tested food substrates. (F\u003csub\u003e\u003cem\u003e8,36\u003c/em\u003e\u003c/sub\u003e = 14.27, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.0001). Larvae reared on cracked wheat exhibited the shortest developmental duration, whereas those on barley flour took the longest to reach pupation (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The observed differences suggest that diet type substantially influences the growth rate of \u003cem\u003eT. granarium\u003c/em\u003e larvae. The pupal period of \u003cem\u003eT. granarium\u003c/em\u003e differed significantly among the tested food substrates (F\u003csub\u003e\u003cem\u003e8,36\u003c/em\u003e\u003c/sub\u003e = 2.57, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.024). Substrate type significantly affected pupal development, resulting in the shortest duration on wheat flour and the longest on whole maize. (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.). Similarly, the percentage of larvae successfully forming pupae varied significantly across diets (F\u003csub\u003e\u003cem\u003e8,36\u003c/em\u003e\u003c/sub\u003e = 47.410, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), with the highest pupation rate observed on cracked wheat and the lowest on cracked barley (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). These findings indicate that both the duration of the pupal stage and the efficiency of pupal formation in \u003cem\u003eT. granarium\u003c/em\u003e are influenced by the type of food substrate available during larval development.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eAdult emergence of \u003cem\u003eT. granarium\u003c/em\u003e varied significantly among the tested food substrates (F\u003csub\u003e\u003cem\u003e8,36\u003c/em\u003e\u003c/sub\u003e = 11.42, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). The highest emergence rate was recorded from larvae reared on wheat flour, while the lowest was from those reared on barley flour. Similarly, adult longevity differed significantly across diets (F\u003csub\u003e\u003cem\u003e8,36\u003c/em\u003e\u003c/sub\u003e = 18.47, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001) with beetles from wheat cracked surviving the longest (44.6 d) and those from barley flour the shortest (24.9 d) (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). These results suggest that the nutritional and physical characteristics of the larval diet not only affect the proportion of individuals successfully reaching adulthood but also influence the lifespan of the emerged beetles. The female-biased sex ratio of \u003cem\u003eT. granarium\u003c/em\u003e did not differ significantly among the food substrates (F₈,₃₆ = 1.01, p\u0026thinsp;\u0026gt;\u0026thinsp;0.447). The highest bias (2.36) was recorded in adults reared on whole wheat, whereas the lowest (1.30) was observed in those reared on barley flour (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe number of F₁ progeny produced by \u003cem\u003eT. granarium\u003c/em\u003e differed significantly among the tested food substrates (F\u003csub\u003e\u003cem\u003e8,36\u003c/em\u003e\u003c/sub\u003e = 175.91, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.0001). The highest mean progeny production was recorded on cracked wheat (92.20%), followed by whole wheat, while the lowest was on whole maize (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e). These differences in progeny output correspond with the observed patterns in adult emergence and longevity, suggesting that diets that support higher survival to adulthood and longer adult lifespan also tend to yield greater reproductive output. The results indicate that the physical and nutritional quality of the food substrate during larval development plays a critical role in determining the reproductive potential of \u003cem\u003eT. granarium\u003c/em\u003e populations.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eGrowth rates of \u003cem\u003eT. granarium\u003c/em\u003e varied significantly among different food substrates (F₈,₃₆ = 17.23, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.0001). The highest growth index (4.88) was recorded on cracked wheat, followed by wheat flour (4.75), whereas the lowest was observed on barley flour (3.15) (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e). Similarly, the percentage of food damage caused by \u003cem\u003eT. granarium\u003c/em\u003e also differed significantly across substrates (F₈,₃₆ = 19.80, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.0001). The maximum damage was recorded on cracked wheat (21.40%), while the minimum occurred on barley flour (12.00%) (Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eHierarchical cluster analysis was performed on the F₁ progeny data of \u003cem\u003eT. granarium\u003c/em\u003e reared on different food substrates to identify similarities in reproductive performance. The resulting dendrogram (Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e) grouped the diets into distinct clusters based on the number of progeny produced. At the selected similarity threshold, two major clusters were performed. The first cluster included wheat, which exhibited relatively higher F₁ progeny numbers, indicating similar suitability for supporting beetle reproduction. The second cluster consisted of maize, characterized by significantly lower progeny output. This clear separation highlights the influence of substrate type on the reproductive potential of \u003cem\u003eT. granarium\u003c/em\u003e. The dendrogram thus visually summarizes the relative reproductive fitness of \u003cem\u003eT. granarium\u003c/em\u003e on the tested diets, reflecting their differential impact on population growth.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003ePrincipal Component Analysis (PCA) was conducted to explore the variation in F₁ progeny production of \u003cem\u003eT. granarium\u003c/em\u003e across the different food substrates. The first two principal components (PC1 and PC2) accounted for 34.9% and 33.4% of the total variation, respectively, together explaining the cumulative variance (Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003e). The PCA biplot revealed a clear separation among the tested diets based on their influence on F₁ progeny output. Diets positioned on the positive side of PC1, such as cracked wheat and whole wheat, were associated with higher F₁ progeny numbers, indicating these substrates provided more favorable conditions for reproduction. In contrast, whole maize, located on the negative side of PC1, correlated with lower progeny production. This ordination suggests that the nutritional and physical characteristics of the substrates significantly affect the reproductive potential of \u003cem\u003eT. granarium\u003c/em\u003e. The clustering of diets in the PCA space highlights similarities in their suitability for supporting the pest\u0026rsquo;s population growth.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eOur results demonstrate that the type of larval diet significantly influenced all major fitness parameters of \u003cem\u003eT. granarium\u003c/em\u003e, confirming and extending patterns reported in earlier studies. The biology and successful rearing of \u003cem\u003eT. granarium\u003c/em\u003e depend heavily on the type of diet (Athanassiou et al. \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2019\u003c/span\u003ea). Wheat and wheat flour support the best development and are ideal for both pest management studies and laboratory maintenance. Understanding food preferences helps improve monitoring (Hodges \u0026amp; Rees \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2012\u003c/span\u003e; Athanassiou et al. \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2018\u003c/span\u003ea), rearing efficiency (Naseri \u0026amp; Borzoui, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2016\u003c/span\u003e, Burges, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e1963\u003c/span\u003e), and control strategy design (Athanassiou, et al. \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2018\u003c/span\u003eb, Wakil et al. \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2015\u003c/span\u003e, Islam et al. \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2010\u003c/span\u003e). The present study demonstrates that food substrate type exerts a marked influence on the development, survival, and reproduction of \u003cem\u003eT. granarium\u003c/em\u003e. Significant variation in larval weight among diets indicates that the nutritional composition and physical characteristics of the substrate play critical roles in larval growth. Larvae reared on cereals attained the greatest mean weight, which is in accordance with the findings of Naseri \u0026amp; Borzoui (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2016\u003c/span\u003e) and Suleiman \u0026amp; Abdullahi (\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). Moreover, Borzoui \u0026amp; Naseri (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2016\u003c/span\u003e) reported that protein- and lipid-rich diets support higher biomass accumulation in \u003cem\u003eT. granarium\u003c/em\u003e. Conversely, the lowest larval weight recorded on legumes and oilseed aligns with the data that have been reported by El-Lakwah et al. (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e1993\u003c/span\u003e), suggesting that low nutritional value and/or reduced digestibility can constrain larval growth.\u003c/p\u003e \u003cp\u003eInterestingly, pupal weight did not vary significantly among diets, implying that once larvae reach the pupal stage, body mass is less influenced by diet quality. However, the significant differences in larval and pupal periods recorded in this study support earlier observations by Burges (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e1963\u003c/span\u003e), El-Lakwah et al. (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e1993\u003c/span\u003e), Naseri \u0026amp; Borzoui (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2016\u003c/span\u003e), and Borzoui \u0026amp; Naseri (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2016\u003c/span\u003e) all showed that diet significantly alters the larval and pupal periods of \u003cem\u003eT. granarium\u003c/em\u003e that substrate quality can accelerate or delay development. The shortest larval and pupal durations on whole may be attributed to its higher nutritional adequacy and narrower weight range, while the prolonged development on flour barley and whole maize suggests poor nutritional suitability and increased energy expenditure during feeding. The proportion of larvae that were successfully pupated and the subsequent adult emergence rates also varied significantly among diets.\u003c/p\u003e \u003cp\u003eThe present study demonstrated that food substrates did not significantly influence the sex ratio of \u003cem\u003eT. granarium\u003c/em\u003e. Although female-biased sex ratios were observed across all diets, statistical analysis revealed no significant differences among substrates. This indicates that sex allocation in \u003cem\u003eT. granarium\u003c/em\u003e may be relatively stable and less dependent on nutritional quality, in contrast to other biological traits such as development time, fecundity, or survival, which are often strongly diet-dependent (Burges, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e1963\u003c/span\u003e; Hagstrum \u0026amp; Subramanyam, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2009\u003c/span\u003e). The slight variation observed, with the highest female bias in whole wheat and the lowest in barley flour, may suggest that nutrient-rich substrates can enhance female emergence to some extent. Similar trends have been reported in other stored-product beetles, where higher-quality diets supported relatively more females, potentially reflecting adaptive strategies for maximizing reproductive output under favorable nutritional conditions (Athanassiou \u0026amp; Arthur, 2018). However, the lack of significant differences in the present study implies that \u003cem\u003eT. granarium\u003c/em\u003e maintains a balanced reproductive strategy regardless of diet, possibly due to its adaptation as a primary pest of stored products. From a management perspective, these findings suggest that altering diet type alone may not strongly affect population sex structure. Since females are the primary contributors to population growth through oviposition, control efforts should focus on reducing overall survival and reproductive success rather than relying on potential shifts in sex ratio.\u003c/p\u003e \u003cp\u003eThe close correspondence between F₁ progeny production, adult emergence, and longevity highlights the fundamental influence of larval diet quality on reproductive capacity. Similar links between enhanced survival, prolonged adult lifespan, and increased fecundity have been documented previously (Borzoui \u0026amp; Naseri, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). In contrast, the diminished progeny production on cracked maize observed here concurs with earlier findings (El-Lakwah et al., \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e1993\u003c/span\u003e; Athanassiou et al., \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2016\u003c/span\u003e) and may be explained by suboptimal nutrient assimilation during larval development. Our results demonstrate that \u003cem\u003eT. granarium\u003c/em\u003e exhibits significantly higher growth indices and food damage potential when reared on cracked wheat, compared to wheat flour and barley flour, which was the least favorable substrate. An earlier work by Naseri and Borzoui (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2016\u003c/span\u003e) on various wheat cultivars revealed that larval weight gain, relative growth rate, and digestive enzyme activity were highest on certain cultivars (e.g., \u0026lsquo;Arg\u0026rsquo;) and lowest on others like 'Parsi' and 'Morvarid', which were considered poor for beetle development. This underscores that substrate quality\u0026mdash;whether due to cultivar-specific nutritional profiles or physical structure\u0026mdash;plays a critical role in \u003cem\u003eT. granarium\u003c/em\u003e\u0026rsquo;s growth.\u003c/p\u003e \u003cp\u003eComparative evaluations of grain genotype susceptibility underline the critical role of inherent grain characteristics. Yousuf et al. (\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2025\u003c/span\u003e) reported that the wheat variety Arooj-2022 sustained significantly higher post-storage damage (up to 17.70% after 90 days) than Akbar-2019 (as low as 4.37%), attributing this divergence to varietal differences in both seed moisture content and inherent resistance traits. Though our study compared different substrate types rather than genotypes, the parallel is clear\u0026mdash;substrate physical and nutritional properties significantly affect both beetle growth and damage inflicted. Earlier studies have shown that barley can strongly favor \u003cem\u003eT. granarium\u003c/em\u003e population growth, supporting shorter generation times, higher fecundity, and increased intrinsic rates of increase relative to other cereals (Karagianni et al., \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). Conversely, barley flour in the present study produced the lowest growth index and damage, indicating that substrate physical form\u0026mdash;flour versus intact grain\u0026mdash;substantially affects larval accessibility and resource utilization and may underlie the contrasting outcomes. The hierarchical cluster analysis and PCA both revealed distinct groupings of diets based on reproductive performance. Diets that clustered together exhibited similar F₁ progeny outputs, reinforcing the concept that diet quality consistently influences reproductive fitness. Such multivariate approaches have also been applied by Sinha et al. (\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e1969\u003c/span\u003e) to identify diet groupings for stored-product insects, highlighting their utility in pest ecology research.\u003c/p\u003e \u003cp\u003eOverall, the findings of this study underscore the importance of food substrate quality in shaping the population dynamics of \u003cem\u003eT. granarium\u003c/em\u003e. By identifying diets that support rapid development, high survival, and elevated reproductive output, these results have practical implications for pest management strategies. For example, in storage facilities, restricting access to nutrient-rich commodities or incorporating less suitable substrates could help suppress \u003cem\u003eT. granarium\u003c/em\u003e populations. Moreover, the observed congruence between our results and those of previous studies strengthens the evidence that diet composition is a key determinant of \u003cem\u003eT. granarium\u003c/em\u003e biology and can be leveraged in integrated pest management programs. The strong concordance between our data and previous studies confirms that grain types high in starch and protein (e.g. wheat, rye) favor \u003cem\u003eT. granarium\u003c/em\u003e development and reproduction, while oil-bearing seeds and legumes (e.g. walnut, almond) are comparatively unsuitable hosts. These insights are highly relevant for storage practices: limiting access to favorable substrates and targeting control efforts in high-risk commodities could help suppress potential population build-up.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eOverall, our results underscore the central role of food substrate quality\u0026mdash;particularly macronutrient composition and digestibility\u0026mdash;in regulating life-history traits and population growth potential of \u003cem\u003eT. granarium\u003c/em\u003e. This interpretation aligns with previous reviews documenting the species\u0026rsquo; exceptional adaptability to hot, dry conditions and its ability to rapidly exploit nutritionally suitable substrates, thereby exacerbating infestation severity (Athanassiou et al. \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2019\u003c/span\u003ea). By confirming earlier observations and expanding them through multivariate clustering approaches, the present work enhances the biological rationale for substrate-focused, integrated pest management strategies in stored-product systems.\u003c/p\u003e "},{"header":"Declarations","content":"\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eAuthors contribution\u003c/h2\u003e \u003cp\u003eTanushree Barman: Data curation, Formal analysis, Investigation,. Shakila Khatun Bristy: Formal analysis, Investigation, Md. Saiful Islam: Methodology, Formal analysis; Paraskevi Agrafioti: Conceptualization, Writing. Christos G. Athanassiou: Conceptualization, Writing - review \u0026amp; editing final draft, Md. Mahbub Hasan: Conceptualization, Methodology, Statistical analysis, writing Original draft.\u003c/p\u003e \u003c/div\u003e \u003cp\u003e \u003cstrong\u003eCompeting interest\u003c/strong\u003e \u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eEthics approval\u003c/strong\u003e \u003cp\u003eThis article does not contain any studies with human participants or animals performed by any of the authors.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e \u003cp\u003eThis research did not receive funding from any organization.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e \u003cp\u003eThe authors are grateful to the Department of Zoology, University of Rajshahi, for providing laboratory facilities and support.\u003c/p\u003e\u003ch2\u003eData availability\u003c/h2\u003e \u003cp\u003eData is provided within the manuscript and raw data will be made available on request.\u003c/p\u003e"},{"header":"References","content":"\u003cp\u003eAgarwal N, Kalra VK, Jalali SK (1988) Influence of food media on growth and fecundity of \u003cem\u003eTrogoderma granarium \u003c/em\u003e(Everts). Indian J Entomol 50:275\u0026ndash;281\u003c/p\u003e\n\u003cp\u003eAl-Jboory SA, Al-Rawy MA (2021) Influence of commodity on the biology of \u003cem\u003eTrogoderma granarium\u003c/em\u003e Everts (Coleoptera: Dermestidae): development, growth, and survival. J Stored Prod Res 94:101881. https://doi.org/10.1016/j.jspr.2021.101881\u003c/p\u003e\n\u003cp\u003eArthur FH, Domingue MJ, Scheff DS, Myers SW (2019) Bioassays and methodologies for insecticide tests with larvae of \u003cem\u003eTrogoderma granarium\u003c/em\u003e (Everts), the khapra beetle. Insects 10:145. https://doi.org/10.3390/insects10050145\u003c/p\u003e\n\u003cp\u003eAthanassiou CG, Phillips TW, Wakil W (2019) Biology and control of the khapra beetle, \u003cem\u003eTrogoderma granarium\u003c/em\u003e, a major quarantine threat to global food security. Annu Rev Entomol 64:131\u0026ndash;148. https://doi.org/10.1146/annurev-ento-011118-111804\u003c/p\u003e\n\u003cp\u003eAthanassiou CG, Arthur FH, Campbell JF (2018) Biological and ecological traits of the khapra beetle, \u003cem\u003eTrogoderma granarium\u003c/em\u003e, a global stored product pest. Annu Rev Entomol 63:131\u0026ndash;148. https://doi.org/10.1146/annurev-ento-020117-043405\u003c/p\u003e\n\u003cp\u003eAthanassiou CG, Arthur FH, Kavallieratos NG (2018) Monitoring stored-product insect pests: traps and attractants. Insects 9:82. https://doi.org/10.3390/insects9030082\u003c/p\u003e\n\u003cp\u003eAthanassiou CG, Kavallieratos NG, Andris NS (2010) Evaluation of various commodities for the development of the yellow mealworm, Tenebrio molitor (Coleoptera: Tenebrionidae). J Stored Prod Res 46:245\u0026ndash;249. https://doi.org/10.1016/j.jspr.2010.05.003\u003c/p\u003e\n\u003cp\u003eAthanassiou CG, Kavallieratos NG, Boukouvala MC (2016) Population growth of the khapra beetle, \u003cem\u003eTrogoderma granarium\u003c/em\u003e Everts (Coleoptera: Dermestidae) on different commodities. J Stored Prod Res 69:72\u0026ndash;77. https://doi.org/10.1016/j.jspr.2016.07.005\u003c/p\u003e\n\u003cp\u003eBhattacharya AK, Pant NC (1969) The effect of different food media on the rate of development of \u003cem\u003eTrogoderma granarium\u003c/em\u003e Everts (Coleoptera: Dermestidae). J Stored Prod Res 5:199\u0026ndash;204. https://doi.org/10.1016/0022-474X(69)90031-5\u003c/p\u003e\n\u003cp\u003eBorzoui E, Naseri B (2016) Effects of dietary protein and carbohydrate balance on growth and reproduction of \u003cem\u003eTrogoderma granarium\u003c/em\u003e. Bull Entomol Res 106:444\u0026ndash;452. https://doi.org/10.1017/S0007485316000122\u003c/p\u003e\n\u003cp\u003eBorzoui E, Athanassiou CG, Kavallieratos NG, et al. (2015) Different diets affecting biology and digestive physiology of \u003cem\u003eTrogoderma granarium\u003c/em\u003e. J Stored Prod Res 62:25\u0026ndash;33. https://doi.org/10.1016/j.jspr.2015.04.001\u003c/p\u003e\n\u003cp\u003eBurges HD (1962) The developmental rate of \u003cem\u003eTrogoderma granarium\u003c/em\u003e Everts (Coleoptera: Dermestidae) in relation to temperature. Bull Entomol Res 53:119\u0026ndash;130. https://doi.org/10.1017/S0007485300048172\u003c/p\u003e\n\u003cp\u003eBurges HD (1963) Studies on the dermestid beetle \u003cem\u003eTrogoderma granarium\u003c/em\u003e Everts. VI. Factors affecting larval growth and survival on cereal grains. Bull Entomol Res 54:751\u0026ndash;765. https://doi.org/10.1017/S0007485300048834\u003c/p\u003e\n\u003cp\u003eCox PD, Simms SG (1978) The fecundity and development of \u003cem\u003eTrogoderma granarium\u003c/em\u003e Everts (Coleoptera: Dermestidae) in relation to temperature. J Stored Prod Res 14:107\u0026ndash;118. https://doi.org/10.1016/0022-474X(78)90027-1\u003c/p\u003e\n\u003cp\u003eEl-Lakwah FA, Mohamed HA, El-Sayed YA (1993) The effect of different diets on the biology and development of the khapra beetle, \u003cem\u003eTrogoderma granarium\u003c/em\u003e Everts. J Appl Entomol 115:179\u0026ndash;185. https://doi.org/10.1111/j.1439-0418.1993.tb00376.x\u003c/p\u003e\n\u003cp\u003eEPPO (2013) Insect meal as renewable source of food for animal feeding: a review. EPPO Bull 43:293\u0026ndash;298. https://doi.org/10.1111/epp.12040\u003c/p\u003e\n\u003cp\u003eGaur RK, Rana SKS, et al. (2022) Developmental response of \u003cem\u003eTrogoderma granarium\u003c/em\u003e Everts to durable wheat cultivars. Int J Trop Insect Sci 42:3525\u0026ndash;3535. https://doi.org/10.1007/s42690-022-00853-z\u003c/p\u003e\n\u003cp\u003eGoyal LN, Gaur RK, et al. (2024) Susceptibility of stored pearl millet products to khapra beetle infestation. J Food Prot 87:100311. https://doi.org/10.1016/j.jfp.2024.100311\u003c/p\u003e\n\u003cp\u003eHagstrum DW, Subramanyam B (2009) Stored-product insect resource. AACC International, St. Paul\u003c/p\u003e\n\u003cp\u003eHodges RJ, Rees DP (2012) Detection methods for \u003cem\u003eTrogoderma granarium\u003c/em\u003e Everts (Coleoptera: Dermestidae): a quarantine pest in stored products. J Stored Prod Res 50:47\u0026ndash;61. https://doi.org/10.1016/j.jspr.2012.04.004\u003c/p\u003e\n\u003cp\u003eIslam MS, Hasan MM, Lei C, Mucha-Pelzer T, Rahman MM, Mewis I (2010) Insecticidal activity of plant oils against \u003cem\u003eTrogoderma granarium\u003c/em\u003e Everts (Coleoptera: Dermestidae). J Stored Prod Res 46:255\u0026ndash;260. https://doi.org/10.1016/j.jspr.2010.05.002\u003c/p\u003e\n\u003cp\u003eKaragianni E, Gasco L, Fountoulaki E (2019) Animals fed insect-based diets: state-of-the-art on digestibility, performance, and product quality. Animals 9:170. https://doi.org/10.3390/ani9040170\u003c/p\u003e\n\u003cp\u003eKavallieratos NG, Athanassiou CG, Arthur FH (2016) Residual efficacy of insecticides on different surfaces against \u003cem\u003eTrogoderma granarium\u003c/em\u003e Everts (Coleoptera: Dermestidae). J Econ Entomol 109:1957\u0026ndash;1964. https://doi.org/10.1093/jee/tow140\u003c/p\u003e\n\u003cp\u003eKavallieratos NG, Nika EP, Skourti A, Ntalli N, Boukouvala MC, Ntalaka CT, Maggi F, Rakotosaona R, Spinozzi E (2022) Essential oil-based nanostructured pesticides: design and performance for control of \u003cem\u003eTrogoderma granarium\u003c/em\u003e (Coleoptera: Dermestidae) adults. Ind Crops Prod 188:115541. https://doi.org/10.1016/j.indcrop.2022.115541\u003c/p\u003e\n\u003cp\u003eKavallieratos D, Rologas M, et al. (2024) Development and population growth of khapra beetle \u003cem\u003eTrogoderma granarium\u003c/em\u003e (Coleoptera: Dermestidae) on different commercial wheat products. J Econ Entomol 117:1451\u0026ndash;1459. https://doi.org/10.1093/jee/toae101\u003c/p\u003e\n\u003cp\u003eNaseri B, Borzoui E (2016) Life cycle and digestive physiology of \u003cem\u003eTrogoderma granarium\u003c/em\u003e (Coleoptera: Dermestidae) on different wheat cultivars. Ann Entomol Soc Am 109:905\u0026ndash;911. https://doi.org/10.1093/aesa/saw048\u003c/p\u003e\n\u003cp\u003eNaseri A, Borzoui G, Naseri B (2023) Comparative development and population growth of \u003cem\u003eTrogoderma granarium\u003c/em\u003e Everts (Coleoptera: Dermestidae) on different wheat cultivars and their milling fractions. J Stored Prod Res 103:102200. https://doi.org/10.1016/j.jspr.2023.102200\u003c/p\u003e\n\u003cp\u003eNayak MK, Collins PJ, et al. (2022) Comparative population growth of the khapra beetle, \u003cem\u003eTrogoderma granarium\u003c/em\u003e (Coleoptera: Dermestidae), on different commodities. J Econ Entomol 115:1030\u0026ndash;1039. https://doi.org/10.1093/jee/toac058\u003c/p\u003e\n\u003cp\u003eR Core Team (2020) R: a language and environment for statistical computing. R Foundation for Statistical Computing, Vienna\u003c/p\u003e\n\u003cp\u003eRajput SA, Khanzada MS, Abro GH, Khanzada SR, Syed TS, Su W (2015) Comparative population growth and losses caused by beetle \u003cem\u003eTrogoderma granarium\u003c/em\u003e (Everts) to selected past and present wheat genotypes. J (Incomplete citation; please verify full title and journal)\u003c/p\u003e\n\u003cp\u003eRao RSV, Raju MVLN, Reddy MR, Panda AK (2004) Replacement of yellow maize with pearl millet (Pennisetum typhoides), foxtail millet (Setaria italica), or finger millet (Eleusine coracana) in broiler chicken diets containing supplemental enzymes. Asian-Australas J Anim Sci 17:836\u0026ndash;842. https://doi.org/10.5713/ajas.2004.836\u003c/p\u003e\n\u003cp\u003eShah PA, Bowers K (2025) A meta-analysis of the global risk thresholds for \u003cem\u003eTrogoderma granarium\u003c/em\u003e establishment under climate change scenarios. Pest Manag Sci (In press; DOI not yet available)\u003c/p\u003e\n\u003cp\u003eSinha RN, Wallace HAH, Chebib FS (1969) Principal component analysis of interrelations among fungi, mites, and insects in grain bulk ecosystems. Ecology 50:536\u0026ndash;547. https://doi.org/10.2307/1933911\u003c/p\u003e\n\u003cp\u003eSuleiman M, Abdullahi G (2014) Nutritional composition of some cereals and legumes and their effects on development of \u003cem\u003eTrogoderma granarium\u003c/em\u003e. J Stored Prod Res 59:87\u0026ndash;93. https://doi.org/10.1016/j.jspr.2014.07.001\u003c/p\u003e\n\u003cp\u003eViljoen JH (1990) The occurrence of\u003cem\u003e Trogoderma\u003c/em\u003e (Coleoptera: Dermestidae) and related species in southern Africa with special reference to T. granarium and its potential to become established. J Stored Prod Res 26:43\u0026ndash;51. https://doi.org/10.1016/0022-474X(90)90010-V\u003c/p\u003e\n\u003cp\u003eWakil W, Ghazanfar MU, Lord JC (2015) Entomopathogenic fungi for the control of the khapra beetle, \u003cem\u003eTrogoderma granarium\u003c/em\u003e. Biol Control 90:1\u0026ndash;10. https://doi.org/10.1016/j.biocontrol.2015.05.015\u003c/p\u003e\n\u003cp\u003eWilches DM, Laird RA, Floate KD, Fields PG (2016) A review of diapause and tolerance to extreme temperatures in dermestids (Coleoptera). J Stored Prod Res 68:50\u0026ndash;62. https://doi.org/10.1016/j.jspr.2016.04.001\u003c/p\u003e\n\u003cp\u003eWilches DM, Laird RA, Floate KD, Fields PG (2019) Control of \u003cem\u003eTrogoderma granarium\u003c/em\u003e (Coleoptera: Dermestidae) using high temperatures. J Econ Entomol 112:963\u0026ndash;968. https://doi.org/10.1093/jee/toy413\u003c/p\u003e\n\u003cp\u003eYadav SK, Srivastava C (2017) Effect of temperature and food on the biology of khapra beetle, \u003cem\u003eTrogoderma granarium\u003c/em\u003e Everts. J Entomol Zool Stud 5:1015\u0026ndash;1019\u003c/p\u003e\n\u003cp\u003eYousuf HMB, Yasin M, Khan MA, Abbasi A, Arshad M, Aqueel MA, Ul Haq I, Alsakkaf WAA, Mackled MI, Rebouh NY, et al. (2025) Assessment of different conventional and biofortified wheat genotypes based on biology and damage pattern of \u003cem\u003eRhyzopertha dominica\u003c/em\u003e and \u003cem\u003eTrogoderma granarium\u003c/em\u003e. Insects 16:66. https://doi.org/10.3390/insects16010066\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Trogoderma granarium, Khapra beetle, growth and development, food substrates, post-harvest loss","lastPublishedDoi":"10.21203/rs.3.rs-8562917/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8562917/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe population dynamics of insect pests in stored products are fundamentally governed by the nutritional quality of their diet. This study quantitatively demonstrates how variations in food substrate directly regulate key life-history parameters, ultimately determining infestation potential and outbreak risk. In this study, we investigated the effect of different food substrates on the development, survival, and reproduction of \u003cem\u003eTrogoderma granarium\u003c/em\u003e under controlled laboratory conditions. As results indicated, the significant variation in larval weight was observed across diets, with the highest weight attained on wheat flour and the lowest on barley flour. Pupal weight did not differ significantly among diets, indicating limited dietary influence on pupal mass. Larval and pupal developmental periods were significantly influenced by diet, with larvae showing the shortest development (15.00\u0026thinsp;\u0026plusmn;\u0026thinsp;0.31 d) on cracked wheat and the longest (19.00\u0026thinsp;\u0026plusmn;\u0026thinsp;0.63 d) on barley flour, whereas pupae developed fastest (5.00\u0026thinsp;\u0026plusmn;\u0026thinsp;0.70 d) on wheat flour and slowest (8.00\u0026thinsp;\u0026plusmn;\u0026thinsp;0.63d) on whole maize. Pupation success was highest on cracked wheat and lowest on cracked barley. Diet significantly influenced adult emergence and longevity, with maximum emergence on wheat flour and minimum emergence on barley flour, whereas adults exhibited the longest lifespan on cracked wheat and the shortest on barley flour. Diet significantly affected F₁ progeny production, with cracked wheat supporting the highest offspring numbers (92.10\u0026thinsp;\u0026plusmn;\u0026thinsp;1.39%) and whole maize the lowest (20.20\u0026thinsp;\u0026plusmn;\u0026thinsp;0.91%). Overall, the findings demonstrate that wheat-based substrates\u0026mdash;especially cracked wheat\u0026mdash;strongly promote the population growth \u003cem\u003eof T. granarium\u003c/em\u003e, highlighting their importance in pest risk assessment and management strategies. Our research establishes that the nutritional matrix of a food substrate is a critical determinant, defining the carrying capacity and growth trajectory of insect pest populations within a commodity.\u003c/p\u003e","manuscriptTitle":"Growth and Development of the Khapra Beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae), on Different Food Substrates","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-01-20 12:51:59","doi":"10.21203/rs.3.rs-8562917/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"7f54151f-beb6-4936-945b-964ce32d081c","owner":[],"postedDate":"January 20th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-03-03T08:27:58+00:00","versionOfRecord":[],"versionCreatedAt":"2026-01-20 12:51:59","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8562917","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8562917","identity":"rs-8562917","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}