Atypical case of pattern disruption in sex proportions of Tabanidae collections with malaise traps in ecuadorian forests

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Brito Vera This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4366284/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 01 Nov, 2024 Read the published version in Biologia → Version 1 posted 5 You are reading this latest preprint version Abstract Male horseflies have low capture rates in Malaise traps, a widely documented pattern observed in numerous ecological studies. We present findings from a specific locality in Ecuador where a departure from this established pattern is observed. In this locality, males accounted for 59.14% of Tabanidae captures. The disruption in capture patterns observed using Malaise traps represents an uncommon feature in the scientific literature and during collections conducted over eight years in Ecuador. Despite the inherent limitations of Malaise traps in capturing male horseflies, it is possible that under specific conditions, such as the presence of optimal aggregation areas for horseflies, Malaise traps may enhance the capture efficiency of males. Additionally, we provide a detailed discussion on the disruption and disparity in capture sex proportions in Tabanidae, commonly reported in the scientific literature. Understanding these aspects of tabanid behavior is essential due to the outbreaks and deaths associated with trypanosomiasis infections in Ecuador. Male Female Tabanidae Aggregation horse flies Figures Figure 1 Figure 2 Figure 3 Introduction Horseflies are dipteran insects that exhibit marked sexual dimorphism with notable ocular separation, which is a highly distinctive morphological attribute. This characteristic, known as holoptic (eyes fused) in males and dichoptic (eyes separated) in females, allows for clear discrimination of horsefly sexes (Mullens 2019 ; do Carmo et al. 2022 ). Various techniques and tools based on flight interception and attraction are used to capture horseflies. These techniques include the use of traps such as Malaise, Manitoba, canopy, NZI, box traps, light traps, as well as chemical attractants and reflection-polarization (Mihok 2002 ; Krolow et al. 2010 ; Mullens 2019 ; Horváth et al. 2020 ). These diverse methodological approaches offer techniques for capturing individuals and exploring the diversity within this family. This includes studying ecological aspects such as behavior and seasonality by analyzing abundance and absence data (Altunsoy and Kılıç 2012 ; Herczeg et al. 2014 ). Malaise traps have demonstrated high efficacy in capturing female horseflies through flight interception, but not of males horseflies. This widely recognized phenomenon has been documented in numerous studies conducted in the world across different regions and latitudes (Krolow et al. 2017 ; Herczeg et al. 2018 ), with few exceptions (Rafael et al. 2021 ). Other alternative methods, such as deploying light traps above the canopy, offer distinct advantages for capturing male horseflies (Krolow et al. 2010 ), well as shiny black plastic oil traps (Krčmar 2013 ) and polarized reflection traps. The latter attract horseflies through positive polarotaxis, because they mistake the reflection produced by the plate for polarized light reflected by bodies of water (Allan et al. 1987 ; Horváth et al. 2008 ; Blaho et al. 2012 ; Horváth et al. 2020 ). However, despite the widespread adoption of Malaise traps, their tendency to disproportionately capture females has led to a significant underrepresentation of males in entomological collections, with males accounting for as little as 3.6% of the specimens (Oliveira et al. 2023 ). Consequently, this gender bias has resulted in a notable deficiency of male specimens in both museum collections and taxonomic records (Krolow et al. 2012 ). Remarkably, in Ecuador, over nearly five decades since the 1970s, reports of significant male horsefly captures using Malaise traps have been conspicuously absent. Thus, the identification of a disruption in this established pattern within an Andean locality prompted our investigation into the underlying hypotheses driving this variation. Materials and methods We conducted a routine preliminary collection in Tiquibuzo and upon observing an abundance of male horseflies, we intensified our collection efforts, which spanned from May to December. During this period, three white Malaise traps were employed. The collections were conducted in a temperate forest patch situated at coordinates 2°1'55.66"S latitude and longitude 79° 5'51.44"W, with an elevation of 2300 meters above sea level (Fig. 1 ). The forest patch is situated in the western Andes, in Tiquibuzo, approximately 10 km from Chillanes canton in Bolívar province, Ecuador. The traps were strategically positioned along trails and clearings within the forest remnant, maintaining an approximate distance of 60 m between each trap. The collected samples were extracted from the collecting jars daily and stored in appropriate plastic containers at optimal temperature. Specimen identification and mounting were carried out at the former National Institute of Hygiene, and subsequently, the collection was donated to the National Institute of Biodiversity (INABIO). To compare the results in Tiquibuzo, we analyzed the information obtained from the values and proportions of collections between males and females from our previous collections between 2008 and 2016 in six other localities in Ecuador, including Galán Arriba, Manabí (1°20'30.69"S − 80°40'39.63"W, 420 masl); Soroche, Cañar (2°28'27.65"S − 79°13'51.24"W); Bosque Protector Prosperina, Guayas (2°9'24"S − 79°57'53"W, 210 masl); Tinajillas, Morona Santiago (3°00’56"S − 78°36’50"W, 2100 masl); Maylas, Azuay (2°59'17"S − 78°40'59"W, 3192 masl); and Plan de Milagro, Morona Santiago (03°00'24.69"S – 78°17'27.20" W, 1100 masl). We then standardized the data from the seven sampling locations due to differences in the temporal intensity of sampling. To do this, we divided the number of females and males in each locality by the number of months of sampling, thus obtaining the monthly abundance of females and males. These values were used to compare the collection frequency by trap for females and males. Initially, we assessed the homoscedasticity and normality of the data using the Levene and Shapiro-Wilk tests, respectively. Subsequently, we compared the two samples of non-parametric data using the Kruskall-Wallis test or the parametric ANOVA test with Welch correction, both with a reference significance value of α = 0.05. Finally, we used a GLM to relate the total monthly abundances of females and males to highlight possible population behavior patterns. Results The continuous collection spanning 39 months distributed over 8 years, across the seven evaluated locations accounted for a mere 4.3% of male individuals out of the total collection of 11,227 individuals. Regarding the normality analyses of female density data, a Shapiro-Wilk (SW) value of 0.85 with a P-value of 0.15 was obtained. For male density, the SW value was 0.62 with a P-value of 0.0005. Additionally, the Levene test for the homogeneity of variance of the means yielded a significant value of P = 0.0007. Based on these metrics, we opted to employ non-parametric Kruskal-Wallis tests to compare the medians. The resulting values were H(chi2) = 7.5 with a P-value of 0.006, indicating significant differences in collection density medians between females and males across the seven analyzed locations. In essence, the Malaise traps captured more females than males. This trend persisted across all locations, except for Tiquibuzo, where the collection percentage of male horseflies was 59.14% (Fig. 2 ). Notably, Tiquibuzo exhibited a higher collection density of males over females, representing a distinct pattern. Additionally, males’ presences were observed in nine out of the ten species over the eight-month collection period, exhibiting a greater abundance from July to November compared to females. In December, the collection was limited to an individual of a single species, indicating the likelihood of populations entering a larval stage during the wet season, which encompasses the period from December to April. Among the species collected, a noteworthy pattern emerged wherein male individuals exhibited percentage dominance in half of the species, which is also atypical in this type of collections. However, no statistically significant differences were observed in the total monthly collections of all species combined in Tiquibuzo, according to the Kruskal-Wallis test for equal medians H (chi 2 ):0.2585, P:0.60. Nevertheless, three out of the ten species found exhibited sex-based differentiation and were statistically significant: Dasybasis schineri (Krober, 1931) Welch test F = 6.263, df = 8.521, P = 0.03509, Eristalotabanus violaceus (Krober, 1931), KW:H(chi 2 ):3.938, P:0.044, and Dicladocera macula (Macquart 1846) KW:H(chi 2 ): 3.692, P:0.045. Finally, we generated GLMs of total monthly abundances between females and males; however, due to short sampling periods and the absolute scarcity of males in some locations, only the Tiquibuzo and Cerro Prosperina sites were evaluated. For Tiquibuzo, a generalized linear model with normal distribution and identity link function was applied. A phi dispersion of 119.19 was estimated. The model coefficients were as follows: for the slope (a), 1.3649 (standard error = 0.331), and for the intercept (b), 1.3892 (standard error = 6.3873). The log-likelihood was − 3. The goodness-of-fit statistic (G) was 17.005, with a p-value for the slope equal to 3.7285 x 10 − 5 . This strong correlation could suggest a balance in horsefly populations in terms of sexes (Fig. 3 ). As for the Prosperina site, a phi dispersion of 7.4023 was estimated. The model coefficients were as follows: for the slope (a), -0.0081143 (standard error = 0.004125), and for the intercept (b), 5.4533 (standard error = 1.7699). The log-likelihood was − 5. The goodness-of-fit statistic (G) was 3.8695, with a p-value for the slope equal to 0, of 0.049. Discussion As previously indicated, male horseflies are captured infrequently, particularly when employing Malaise traps (Krolow et al. 2012 ). Consequently, it is paradoxical to observe a higher representation of 59.14% and male dominance over a span of seven months in half of the encountered species in Tiquibuzo. We understand that despite the Tiquibuzo data regarding monthly collections not being statistically significant, nonetheless the mere fact of representing almost 60% of the total collections in Tiquibuzo is puzzling considering the extensive dataset spanning nearly eight years of our studies and collections across different months in Ecuador. Undoubtedly, the results indicate, a distinct deviation from the patterns documented in the scientific literature with malaise trap. However, it has been reported that the capture rate of males tends to increase significantly with other mechanisms, such as light trapping in the forest canopy, resulting in representation levels of up to 63% (Krolow et al. 2010 ). Similarly, studies in salt marshes using emergence traps have consistently shown comparable proportions of male and female individuals (Cookson 1967 ; Rockel and Hansens 1970 ). These traps exhibit notable parity in the proportion of females and males collected. This suggests that certain populations have comparable sex ratios, although field observations indicate that sex ratios vary among species and seasons. We noted this phenomenon during our field collections in Tiquibuzo, where overall monthly abundances showed no significant variation, except in three instances where male prevalence exceeded that of females. This observation hints at a potential sex-related dynamic in the population structure. Similarly, our analysis using Generalized Linear Models (GLMs) revealed a direct correlation between male and female monthly abundances, as illustrated in Fig. 3 . Hence, the primary inquiry should revolve around the reasons behind the elevated male capture rates observed in Tiquibuzo using Malaise traps, as well as the underlying factors contributing to the generally low capture rates of males with these traps. To tackle these inquiries, there are several hypotheses to consider, such as the males horseflies are dominant in the initial emergence, but they become a minority toward the end of the emergence period (Cookson 1967 ), although this pattern was not evidenced in Tiquibuzo. Also, there are instances where males have been observed to have shorter lifespans than females (Karandinos and Axtell 1967 ; Lane et al. 1983 ; Matsumura 1995 ). Hence, if males do indeed exhibit shorter lifespans, the likelihood of encountering and capturing them would correspondingly decrease. The hilltopping behavior hypothesis refers to the behavior of certain insect species that select hill or mountain tops as sites for aggregation and reproduction (Skevington 2008 ). While this phenomenon has been well documented in some insect families, including Tabanidae (Cookson 1967 ; Smith et al. 1994 ; Braga da Rosa 2006), the available evidence for this behavior in Tabanidae is limited compared to other groups such as lepidopterans. Other reports also suggest the presence of preferred areas on hilltops, where males were captured more frequently using entomological nets, even during mating activity (Leprince et al. 1983 ). The study area, Tiquibuzo, is situated in a valley, therefore, the hilltopping behavior hypothesis (Braga da Rosa 2006; Yuval 2006 ; Skevington 2008 ) would not be suitable to explain the observed disruption, as the traps were placed in the valley at an altitude of 2300 m, in the foothills. In other locations, such as the Fernando de Noronha Archipelago in Brazil, a significant number of male individuals of Tabanus occidentalis were captured using Malaise traps. Apparently, the collections at this specific site were near the summit of the island and represented one of the best-preserved areas (Rafael et al. 2021 ), contrary to Tiquibuzo, which exhibited vegetative patches and anthropogenic activity. The evidence suggests that certain members of the Tabanidae family display swarm mating behavior, circling flight and hovering activity, although a substantial portion of reproductive behavior in Tabanidae remains unknown. In other words, certain horsefly species have specific reproductive areas, such as hilltop clearings, where males would be present more frequently, potentially increasing their capture rate (Bailey 1948 ; Sullivan 1981 ; Mullens and Freeman 2017 ; Yuval 2006 ). However, in Tiquibuzo, no mating behavior such as swarms or concentric flights were observed (Yuval 2006 ). Another hypothesis we consider is the differential foraging hypothesis between females and males, which could account for the low collection rate of females in Malaise traps. This hypothesis partially explains how the search for prey and resources can affect the capture frequency in Malaise traps. The feeding and foraging behavior of horseflies exhibits substantial differences between females and males. Female horseflies are typically facultative and can opportunistically consume blood, nectar and pollen to fulfill their energy requirements for flight, reproduction and oviposition (Leprince et al. 1983 ; Karolyi et al. 2014 ; Mullens 2019 ). Some of their prey, including mammals, reptiles and birds, exhibit evasion and defense behaviors to avoid horsefly bites (Limeira de Oliveira et al. 2002 ; Barros and Foil 2007 ; Caro et al. 2014 ; Altunsoy 2015 ), indicating that the foraging behavior of female horseflies can be energetically demanding, therefore, the blood intake provides them with advantages such as increased escape speed (Horváth et al. 2020 ). This energetic investment in foraging would enhance the likelihood of encountering prey due to an increase in flight frequency; however, it would also raise the probability of being captured in Malaise traps. In contrast to females, male horseflies display specialized feeding behavior, exclusively relying on pollen and nectar consumption. However, the energetic costs associated with foraging and reproductive activity, particularly during hovering flight, can be substantial for males (Smith et al. 1994 ; Smith 2013 ) and our understanding of male horseflies' energy expenditure and specific feeding patterns remains limited (Allan et al. 1987 ). Male horseflies are frequently observed in close proximity to water bodies or moist areas along the banks of rivers or lagoons, resulting in a significant focus of the literature on their behavior in such habitats. These areas serve as aggregation sites for reproduction (Cookson 1967 ; Mullens and Freeman 2017 ). However, in Tiquibuzo, no significant bodies of water in the area, only small rivulets, eliminating a reference area for males to orient through positive polarotaxis generated by water reflections, which is crucial for male-female aggregation and courtship (Horváth et al. 2008 ; Herczeg et al. 2014 ). In the forest, certain horsefly species appears to exhibit a preference for flying higher in the tree canopy (Krolow et al. 2010 ). Therefore, collecting samples in the understory would reduce the likelihood of intercepting them with malaise traps. The hypothesis that emerges as the most plausible is that of an optimal aggregation zone , suggesting that in certain areas of Tiquibuzo provides favorable conditions for development and feeding. Therefore, a higher density of male and female horseflies would increase the likelihood of capturing them with the Malaise traps, despite their inefficiency for this purpose. This suggests that these optimal aggregation zones exist despite the absence of bodies of water or hilltopping effects. Finally, the impact of habitat reduction and forest fragmentation cannot be disregarded. Species' behaviors tend to change as their habitat is fragmented, as observed in forest patches (Debinski and Holt 2000 ; Harris and Johnson 2004 ; Baldacchino et al. 2014 ). A decrease in available habitat creates pressure for optimal reproductive spaces, compelling many species to modify their behavior and coexist with domestic fauna, benefiting from feeding on livestock (Barros and Foil 2007 ; Baldacchino et al. 2017 ). It is suggested that the reduction of forests and the presence of patches could alter the behavioral ecology of reproduction and foraging in horseflies, potentially resulting in a decrease in aggregation areas. Within the study area, the traps were positioned in a small forest patch; however, this patch serves as a corridor connecting to a larger forest patch, facilitating the movement of both male and female horseflies. Females would acquire resources from nearby livestock and the flora and fauna in the more densely vegetated interior of the forest, where they would collect pollen and nectar, similar to male horseflies (Barros and Foil 2007 ); subsequently, they would reassemble in this optimal zone. This behavior is possible because studies using marking and weighing techniques have demonstrated that male horseflies exhibit site fidelity, and return to their breeding sites after feeding activities (Smith 2013 ). Conclusions Horseflies appear to have optimal zones where they are more abundant. Consequently, positioning Malaise traps closer to these focal points, which serve as optimal aggregation zone , would increase the likelihood of capturing them and thus reducing the disparity in collection between males and females. However, such optimal zones are likely to be scarce; otherwise, we would not observe the scarcity of male specimens in Malaise traps, current collections and museum holdings. While Malaise traps are essential for capturing local species diversity, including horseflies, they have inherent biases that limit their effectiveness in capturing the male population of this family. Therefore, it is advisable to complement them with additional trapping mechanisms, such as light traps, polarized refraction traps, and emergence traps, among others, to increase the probability of collecting males. The particular case in the locality of Tiquibuzo represents a fascinating record as it serves as an ideal convergence point for both male and female horseflies, as shown by the presence of males in almost all species, without hilltopping or bodies of water being the sole direct cause of such disruption in the observed pattern. Declarations Conflict of Interest Statement The authors have no conflict of interest. Funding No funding was received for conducting this study. Acknowledgments We sincerely thank Mr. Carlos for allowing us to carry out the trapping phase in his estate. 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J Insect Behav 7:355-383. https://doi.org/10.1007/BF01989741 Sullivan RT (1981) Insect swarming and mating. Fla Entomol 64:44-65. https://doi.org/10.2307/3494600 Yuval B (2006) Mating systems of blood-feeding flies. Annu Rev Entomol 51:413-440. https://doi.org/10.1146/annurev.ento.51.110104.151058 Cite Share Download PDF Status: Published Journal Publication published 01 Nov, 2024 Read the published version in Biologia → Version 1 posted Editorial decision: Minor revisions 12 Jul, 2024 Reviewers agreed at journal 01 Jun, 2024 Reviewers invited by journal 31 May, 2024 Editor assigned by journal 08 May, 2024 First submitted to journal 06 May, 2024 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. 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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-4366284","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":308929650,"identity":"82ae3569-8b4f-4d47-b54f-579f022c71c1","order_by":0,"name":"Jaime Buestan","email":"","orcid":"","institution":"Universidad de Guayaquil Facultad de Ciencias Naturales","correspondingAuthor":false,"prefix":"","firstName":"Jaime","middleName":"","lastName":"Buestan","suffix":""},{"id":308929651,"identity":"88103ccf-c4db-477b-95ca-41837f600eb0","order_by":1,"name":"Gabriel A. Brito Vera","email":"data:image/png;base64,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","orcid":"https://orcid.org/0000-0003-0214-9979","institution":"Pontifical Catholic University of Chile: Pontificia Universidad Catolica de Chile","correspondingAuthor":true,"prefix":"","firstName":"Gabriel","middleName":"A. Brito","lastName":"Vera","suffix":""}],"badges":[],"createdAt":"2024-05-04 01:32:59","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4366284/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4366284/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s11756-024-01819-x","type":"published","date":"2024-11-01T16:20:38+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":58309826,"identity":"7a8cf4f6-3cb1-4cb9-8488-330e722f081e","added_by":"auto","created_at":"2024-06-13 18:58:21","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":671275,"visible":true,"origin":"","legend":"\u003cp\u003eMap of the sampled locations in Ecuador (colored circles). At the bottom of the figure the Bolívar province. It also displays the study area of Tiquibuzo with NDVI vegetation gradients.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-4366284/v1/faee025da469416ed350705d.png"},{"id":58310008,"identity":"50114ff9-1226-4605-a383-bc495f3bd712","added_by":"auto","created_at":"2024-06-13 19:06:21","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":690312,"visible":true,"origin":"","legend":"\u003cp\u003eMonthly distribution of Tabanidae, illustrating an atypical pattern in male capture, both in monthly abundance distribution and the overall relative abundances of the collection.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-4366284/v1/8a6721444fbdf88a3003bc96.png"},{"id":58309825,"identity":"2f0435b9-7b96-4bc0-aef4-8cde5083d539","added_by":"auto","created_at":"2024-06-13 18:58:21","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":12397,"visible":true,"origin":"","legend":"\u003cp\u003eGLM of total monthly abundances between females and males\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-4366284/v1/9592aba6d0443e0374eade79.png"},{"id":68207302,"identity":"52981fd1-a42e-4560-8119-1e2cb0622ea8","added_by":"auto","created_at":"2024-11-04 16:36:40","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1937215,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4366284/v1/0ae95939-089b-463d-b54e-084f11ee5a2f.pdf"}],"financialInterests":"","formattedTitle":"Atypical case of pattern disruption in sex proportions of Tabanidae collections with malaise traps in ecuadorian forests","fulltext":[{"header":"Introduction","content":"\u003cp\u003eHorseflies are dipteran insects that exhibit marked sexual dimorphism with notable ocular separation, which is a highly distinctive morphological attribute. This characteristic, known as holoptic (eyes fused) in males and dichoptic (eyes separated) in females, allows for clear discrimination of horsefly sexes (Mullens \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; do Carmo et al. \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eVarious techniques and tools based on flight interception and attraction are used to capture horseflies. These techniques include the use of traps such as Malaise, Manitoba, canopy, NZI, box traps, light traps, as well as chemical attractants and reflection-polarization (Mihok \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2002\u003c/span\u003e; Krolow et al. \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Mullens \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Horv\u0026aacute;th et al. \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). These diverse methodological approaches offer techniques for capturing individuals and exploring the diversity within this family. This includes studying ecological aspects such as behavior and seasonality by analyzing abundance and absence data (Altunsoy and Kılı\u0026ccedil; \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2012\u003c/span\u003e; Herczeg et al. \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2014\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eMalaise traps have demonstrated high efficacy in capturing female horseflies through flight interception, but not of males horseflies. This widely recognized phenomenon has been documented in numerous studies conducted in the world across different regions and latitudes (Krolow et al. \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Herczeg et al. \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2018\u003c/span\u003e), with few exceptions (Rafael et al. \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Other alternative methods, such as deploying light traps above the canopy, offer distinct advantages for capturing male horseflies (Krolow et al. \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2010\u003c/span\u003e), well as shiny black plastic oil traps (Krčmar \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2013\u003c/span\u003e) and polarized reflection traps. The latter attract horseflies through positive polarotaxis, because they mistake the reflection produced by the plate for polarized light reflected by bodies of water (Allan et al. \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1987\u003c/span\u003e; Horv\u0026aacute;th et al. \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2008\u003c/span\u003e; Blaho et al. \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2012\u003c/span\u003e; Horv\u0026aacute;th et al. \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). However, despite the widespread adoption of Malaise traps, their tendency to disproportionately capture females has led to a significant underrepresentation of males in entomological collections, with males accounting for as little as 3.6% of the specimens (Oliveira et al. \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Consequently, this gender bias has resulted in a notable deficiency of male specimens in both museum collections and taxonomic records (Krolow et al. \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). Remarkably, in Ecuador, over nearly five decades since the 1970s, reports of significant male horsefly captures using Malaise traps have been conspicuously absent. Thus, the identification of a disruption in this established pattern within an Andean locality prompted our investigation into the underlying hypotheses driving this variation.\u003c/p\u003e"},{"header":"Materials and methods","content":"\u003cp\u003eWe conducted a routine preliminary collection in Tiquibuzo and upon observing an abundance of male horseflies, we intensified our collection efforts, which spanned from May to December. During this period, three white Malaise traps were employed. The collections were conducted in a temperate forest patch situated at coordinates 2\u0026deg;1'55.66\"S latitude and longitude 79\u0026deg; 5'51.44\"W, with an elevation of 2300 meters above sea level (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The forest patch is situated in the western Andes, in Tiquibuzo, approximately 10 km from Chillanes canton in Bol\u0026iacute;var province, Ecuador. The traps were strategically positioned along trails and clearings within the forest remnant, maintaining an approximate distance of 60 m between each trap. The collected samples were extracted from the collecting jars daily and stored in appropriate plastic containers at optimal temperature. Specimen identification and mounting were carried out at the former National Institute of Hygiene, and subsequently, the collection was donated to the National Institute of Biodiversity (INABIO).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eTo compare the results in Tiquibuzo, we analyzed the information obtained from the values and proportions of collections between males and females from our previous collections between 2008 and 2016 in six other localities in Ecuador, including Gal\u0026aacute;n Arriba, Manab\u0026iacute; (1\u0026deg;20'30.69\"S \u0026minus;\u0026thinsp;80\u0026deg;40'39.63\"W, 420 masl); Soroche, Ca\u0026ntilde;ar (2\u0026deg;28'27.65\"S \u0026minus;\u0026thinsp;79\u0026deg;13'51.24\"W); Bosque Protector Prosperina, Guayas (2\u0026deg;9'24\"S \u0026minus;\u0026thinsp;79\u0026deg;57'53\"W, 210 masl); Tinajillas, Morona Santiago (3\u0026deg;00\u0026rsquo;56\"S \u0026minus;\u0026thinsp;78\u0026deg;36\u0026rsquo;50\"W, 2100 masl); Maylas, Azuay (2\u0026deg;59'17\"S \u0026minus;\u0026thinsp;78\u0026deg;40'59\"W, 3192 masl); and Plan de Milagro, Morona Santiago (03\u0026deg;00'24.69\"S \u0026ndash; 78\u0026deg;17'27.20\" W, 1100 masl). We then standardized the data from the seven sampling locations due to differences in the temporal intensity of sampling. To do this, we divided the number of females and males in each locality by the number of months of sampling, thus obtaining the monthly abundance of females and males. These values were used to compare the collection frequency by trap for females and males. Initially, we assessed the homoscedasticity and normality of the data using the Levene and Shapiro-Wilk tests, respectively. Subsequently, we compared the two samples of non-parametric data using the Kruskall-Wallis test or the parametric ANOVA test with Welch correction, both with a reference significance value of α\u0026thinsp;=\u0026thinsp;0.05. Finally, we used a GLM to relate the total monthly abundances of females and males to highlight possible population behavior patterns.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eThe continuous collection spanning 39 months distributed over 8 years, across the seven evaluated locations accounted for a mere 4.3% of male individuals out of the total collection of 11,227 individuals. Regarding the normality analyses of female density data, a Shapiro-Wilk (SW) value of 0.85 with a P-value of 0.15 was obtained. For male density, the SW value was 0.62 with a P-value of 0.0005. Additionally, the Levene test for the homogeneity of variance of the means yielded a significant value of P\u0026thinsp;=\u0026thinsp;0.0007. Based on these metrics, we opted to employ non-parametric Kruskal-Wallis tests to compare the medians. The resulting values were H(chi2)\u0026thinsp;=\u0026thinsp;7.5 with a P-value of 0.006, indicating significant differences in collection density medians between females and males across the seven analyzed locations. In essence, the Malaise traps captured more females than males. This trend persisted across all locations, except for Tiquibuzo, where the collection percentage of male horseflies was 59.14% (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Notably, Tiquibuzo exhibited a higher collection density of males over females, representing a distinct pattern. Additionally, males\u0026rsquo; presences were observed in nine out of the ten species over the eight-month collection period, exhibiting a greater abundance from July to November compared to females. In December, the collection was limited to an individual of a single species, indicating the likelihood of populations entering a larval stage during the wet season, which encompasses the period from December to April. Among the species collected, a noteworthy pattern emerged wherein male individuals exhibited percentage dominance in half of the species, which is also atypical in this type of collections. However, no statistically significant differences were observed in the total monthly collections of all species combined in Tiquibuzo, according to the Kruskal-Wallis test for equal medians H (chi\u003csup\u003e2\u003c/sup\u003e):0.2585, P:0.60. Nevertheless, three out of the ten species found exhibited sex-based differentiation and were statistically significant: \u003cem\u003eDasybasis schineri\u003c/em\u003e (Krober, 1931) Welch test F\u0026thinsp;=\u0026thinsp;6.263, df\u0026thinsp;=\u0026thinsp;8.521, P\u0026thinsp;=\u0026thinsp;0.03509, \u003cem\u003eEristalotabanus violaceus\u003c/em\u003e (Krober, 1931), KW:H(chi\u003csup\u003e2\u003c/sup\u003e):3.938, P:0.044, and \u003cem\u003eDicladocera macula\u003c/em\u003e (Macquart 1846) KW:H(chi\u003csup\u003e2\u003c/sup\u003e): 3.692, P:0.045.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFinally, we generated GLMs of total monthly abundances between females and males; however, due to short sampling periods and the absolute scarcity of males in some locations, only the Tiquibuzo and Cerro Prosperina sites were evaluated. For Tiquibuzo, a generalized linear model with normal distribution and identity link function was applied. A phi dispersion of 119.19 was estimated. The model coefficients were as follows: for the slope (a), 1.3649 (standard error\u0026thinsp;=\u0026thinsp;0.331), and for the intercept (b), 1.3892 (standard error\u0026thinsp;=\u0026thinsp;6.3873). The log-likelihood was \u0026minus;\u0026thinsp;3. The goodness-of-fit statistic (G) was 17.005, with a p-value for the slope equal to 3.7285 x 10\u003csup\u003e\u0026minus;\u0026thinsp;5\u003c/sup\u003e. This strong correlation could suggest a balance in horsefly populations in terms of sexes (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). As for the Prosperina site, a phi dispersion of 7.4023 was estimated. The model coefficients were as follows: for the slope (a), -0.0081143 (standard error\u0026thinsp;=\u0026thinsp;0.004125), and for the intercept (b), 5.4533 (standard error\u0026thinsp;=\u0026thinsp;1.7699). The log-likelihood was \u0026minus;\u0026thinsp;5. The goodness-of-fit statistic (G) was 3.8695, with a p-value for the slope equal to 0, of 0.049.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eAs previously indicated, male horseflies are captured infrequently, particularly when employing Malaise traps (Krolow et al. \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). Consequently, it is paradoxical to observe a higher representation of 59.14% and male dominance over a span of seven months in half of the encountered species in Tiquibuzo. We understand that despite the Tiquibuzo data regarding monthly collections not being statistically significant, nonetheless the mere fact of representing almost 60% of the total collections in Tiquibuzo is puzzling considering the extensive dataset spanning nearly eight years of our studies and collections across different months in Ecuador. Undoubtedly, the results indicate, a distinct deviation from the patterns documented in the scientific literature with malaise trap. However, it has been reported that the capture rate of males tends to increase significantly with other mechanisms, such as light trapping in the forest canopy, resulting in representation levels of up to 63% (Krolow et al. \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2010\u003c/span\u003e). Similarly, studies in salt marshes using emergence traps have consistently shown comparable proportions of male and female individuals (Cookson \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e1967\u003c/span\u003e; Rockel and Hansens \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e1970\u003c/span\u003e). These traps exhibit notable parity in the proportion of females and males collected. This suggests that certain populations have comparable sex ratios, although field observations indicate that sex ratios vary among species and seasons. We noted this phenomenon during our field collections in Tiquibuzo, where overall monthly abundances showed no significant variation, except in three instances where male prevalence exceeded that of females. This observation hints at a potential sex-related dynamic in the population structure. Similarly, our analysis using Generalized Linear Models (GLMs) revealed a direct correlation between male and female monthly abundances, as illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. Hence, the primary inquiry should revolve around the reasons behind the elevated male capture rates observed in Tiquibuzo using Malaise traps, as well as the underlying factors contributing to the generally low capture rates of males with these traps. To tackle these inquiries, there are several hypotheses to consider, such as the males horseflies are dominant in the initial emergence, but they become a minority toward the end of the emergence period (Cookson \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e1967\u003c/span\u003e), although this pattern was not evidenced in Tiquibuzo. Also, there are instances where males have been observed to have shorter lifespans than females (Karandinos and Axtell \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e1967\u003c/span\u003e; Lane et al. \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e1983\u003c/span\u003e; Matsumura \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e1995\u003c/span\u003e). Hence, if males do indeed exhibit shorter lifespans, the likelihood of encountering and capturing them would correspondingly decrease.\u003c/p\u003e \u003cp\u003eThe \u003cem\u003ehilltopping behavior hypothesis\u003c/em\u003e refers to the behavior of certain insect species that select hill or mountain tops as sites for aggregation and reproduction (Skevington \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). While this phenomenon has been well documented in some insect families, including Tabanidae (Cookson \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e1967\u003c/span\u003e; Smith et al. \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e1994\u003c/span\u003e; Braga da Rosa 2006), the available evidence for this behavior in Tabanidae is limited compared to other groups such as lepidopterans. Other reports also suggest the presence of preferred areas on hilltops, where males were captured more frequently using entomological nets, even during mating activity (Leprince et al. \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e1983\u003c/span\u003e). The study area, Tiquibuzo, is situated in a valley, therefore, the hilltopping behavior hypothesis (Braga da Rosa 2006; Yuval \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Skevington \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2008\u003c/span\u003e) would not be suitable to explain the observed disruption, as the traps were placed in the valley at an altitude of 2300 m, in the foothills. In other locations, such as the Fernando de Noronha Archipelago in Brazil, a significant number of male individuals of Tabanus occidentalis were captured using Malaise traps. Apparently, the collections at this specific site were near the summit of the island and represented one of the best-preserved areas (Rafael et al. \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2021\u003c/span\u003e), contrary to Tiquibuzo, which exhibited vegetative patches and anthropogenic activity.\u003c/p\u003e \u003cp\u003eThe evidence suggests that certain members of the Tabanidae family display swarm mating behavior, circling flight and hovering activity, although a substantial portion of reproductive behavior in Tabanidae remains unknown. In other words, certain horsefly species have specific reproductive areas, such as hilltop clearings, where males would be present more frequently, potentially increasing their capture rate (Bailey \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e1948\u003c/span\u003e; Sullivan \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e1981\u003c/span\u003e; Mullens and Freeman \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Yuval \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e2006\u003c/span\u003e). However, in Tiquibuzo, no mating behavior such as swarms or concentric flights were observed (Yuval \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e2006\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAnother hypothesis we consider is the \u003cem\u003edifferential foraging hypothesis\u003c/em\u003e between females and males, which could account for the low collection rate of females in Malaise traps. This hypothesis partially explains how the search for prey and resources can affect the capture frequency in Malaise traps. The feeding and foraging behavior of horseflies exhibits substantial differences between females and males. Female horseflies are typically facultative and can opportunistically consume blood, nectar and pollen to fulfill their energy requirements for flight, reproduction and oviposition (Leprince et al. \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e1983\u003c/span\u003e; Karolyi et al. \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; Mullens \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). Some of their prey, including mammals, reptiles and birds, exhibit evasion and defense behaviors to avoid horsefly bites (Limeira de Oliveira et al. \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2002\u003c/span\u003e; Barros and Foil \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2007\u003c/span\u003e; Caro et al. \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; Altunsoy \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2015\u003c/span\u003e), indicating that the foraging behavior of female horseflies can be energetically demanding, therefore, the blood intake provides them with advantages such as increased escape speed (Horv\u0026aacute;th et al. \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). This energetic investment in foraging would enhance the likelihood of encountering prey due to an increase in flight frequency; however, it would also raise the probability of being captured in Malaise traps. In contrast to females, male horseflies display specialized feeding behavior, exclusively relying on pollen and nectar consumption. However, the energetic costs associated with foraging and reproductive activity, particularly during hovering flight, can be substantial for males (Smith et al. \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e1994\u003c/span\u003e; Smith \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2013\u003c/span\u003e) and our understanding of male horseflies' energy expenditure and specific feeding patterns remains limited (Allan et al. \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1987\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eMale horseflies are frequently observed in close proximity to water bodies or moist areas along the banks of rivers or lagoons, resulting in a significant focus of the literature on their behavior in such habitats. These areas serve as aggregation sites for reproduction (Cookson \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e1967\u003c/span\u003e; Mullens and Freeman \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). However, in Tiquibuzo, no significant bodies of water in the area, only small rivulets, eliminating a reference area for males to orient through positive polarotaxis generated by water reflections, which is crucial for male-female aggregation and courtship (Horv\u0026aacute;th et al. \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2008\u003c/span\u003e; Herczeg et al. \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). In the forest, certain horsefly species appears to exhibit a preference for flying higher in the tree canopy (Krolow et al. \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2010\u003c/span\u003e). Therefore, collecting samples in the understory would reduce the likelihood of intercepting them with malaise traps.\u003c/p\u003e \u003cp\u003eThe hypothesis that emerges as the most plausible is that of an \u003cem\u003eoptimal aggregation zone\u003c/em\u003e, suggesting that in certain areas of Tiquibuzo provides favorable conditions for development and feeding. Therefore, a higher density of male and female horseflies would increase the likelihood of capturing them with the Malaise traps, despite their inefficiency for this purpose. This suggests that these optimal aggregation zones exist despite the absence of bodies of water or hilltopping effects.\u003c/p\u003e \u003cp\u003eFinally, the impact of \u003cem\u003ehabitat reduction and forest fragmentation\u003c/em\u003e cannot be disregarded. Species' behaviors tend to change as their habitat is fragmented, as observed in forest patches (Debinski and Holt \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2000\u003c/span\u003e; Harris and Johnson \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2004\u003c/span\u003e; Baldacchino et al. \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). A decrease in available habitat creates pressure for optimal reproductive spaces, compelling many species to modify their behavior and coexist with domestic fauna, benefiting from feeding on livestock (Barros and Foil \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2007\u003c/span\u003e; Baldacchino et al. \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). It is suggested that the reduction of forests and the presence of patches could alter the behavioral ecology of reproduction and foraging in horseflies, potentially resulting in a decrease in aggregation areas. Within the study area, the traps were positioned in a small forest patch; however, this patch serves as a corridor connecting to a larger forest patch, facilitating the movement of both male and female horseflies. Females would acquire resources from nearby livestock and the flora and fauna in the more densely vegetated interior of the forest, where they would collect pollen and nectar, similar to male horseflies (Barros and Foil \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2007\u003c/span\u003e); subsequently, they would reassemble in this optimal zone. This behavior is possible because studies using marking and weighing techniques have demonstrated that male horseflies exhibit site fidelity, and return to their breeding sites after feeding activities (Smith \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2013\u003c/span\u003e).\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eHorseflies appear to have optimal zones where they are more abundant. Consequently, positioning Malaise traps closer to these focal points, which serve as \u003cem\u003eoptimal aggregation zone\u003c/em\u003e, would increase the likelihood of capturing them and thus reducing the disparity in collection between males and females. However, such optimal zones are likely to be scarce; otherwise, we would not observe the scarcity of male specimens in Malaise traps, current collections and museum holdings.\u003c/p\u003e \u003cp\u003eWhile Malaise traps are essential for capturing local species diversity, including horseflies, they have inherent biases that limit their effectiveness in capturing the male population of this family. Therefore, it is advisable to complement them with additional trapping mechanisms, such as light traps, polarized refraction traps, and emergence traps, among others, to increase the probability of collecting males.\u003c/p\u003e \u003cp\u003eThe particular case in the locality of Tiquibuzo represents a fascinating record as it serves as an ideal convergence point for both male and female horseflies, as shown by the presence of males in almost all species, without hilltopping or bodies of water being the sole direct cause of such disruption in the observed pattern.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eConflict of Interest Statement\u003c/h2\u003e \u003cp\u003eThe authors have no conflict of interest.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e \u003cp\u003eNo funding was received for conducting this study.\u003c/p\u003e\u003ch2\u003eAcknowledgments\u003c/h2\u003e \u003cp\u003eWe sincerely thank Mr. Carlos for allowing us to carry out the trapping phase in his estate. We also express our gratitude to the National Institute of Hygiene and Tropical Medicine Leopoldo Izquieta Perez (currently INSPI) for their invaluable logistic support and mobilization. Lastly, we extend special thanks to Elizabeth Mendoza for her significant contribution in the collection and processing of samples.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAllan SA, Day JF, Edman JD (1987) Visual ecology of biting flies. Ann Rev Entomol 32:297-314. https://doi.org/10.1146/annurev.ento.32.1.297 \u003c/li\u003e\n\u003cli\u003eAltunsoy F (2015) Host and feeding side preferences of the horse flies (Diptera: Tabanidae). J Entomol Res Soc 17:107-115.\u003c/li\u003e\n\u003cli\u003eAltunsoy F, Kılı\u0026ccedil; A (2012) Seasonal Abundance of Horse Fly (Diptera: Tabanidae) in Western Anatolia. 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Springer, Dordrecht. https://doi.org/10.1007/978-1-4020-6359-6_1342 \u003c/li\u003e\n\u003cli\u003eSmith S (2013) Survivorship, site fidelity and weight dynamics of male \u003cem\u003eHybomitra aurilimba\u003c/em\u003e (Diptera: Tabanidae) at a hilltop mating arena. Figshare.\u003c/li\u003e\n\u003cli\u003eSmith SM, Turnbull DA, Taylor PD (1994) Assembly, mating, and energetics of \u003cem\u003eHybomitra arpadi\u003c/em\u003e (Diptera: Tabanidae) at Churchill, Manitoba. J Insect Behav 7:355-383. https://doi.org/10.1007/BF01989741 \u003c/li\u003e\n\u003cli\u003eSullivan RT (1981) Insect swarming and mating. Fla Entomol 64:44-65. https://doi.org/10.2307/3494600 \u003c/li\u003e\n\u003cli\u003eYuval B (2006) Mating systems of blood-feeding flies. Annu Rev Entomol 51:413-440. https://doi.org/10.1146/annurev.ento.51.110104.151058\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"biologia","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"biol","sideBox":"Learn more about [Biologia](http://link.springer.com/journal/11756)","snPcode":"11756","submissionUrl":"https://www.editorialmanager.com/biol/default2.aspx","title":"Biologia","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Male, Female, Tabanidae, Aggregation, horse flies","lastPublishedDoi":"10.21203/rs.3.rs-4366284/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4366284/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eMale horseflies have low capture rates in Malaise traps, a widely documented pattern observed in numerous ecological studies. We present findings from a specific locality in Ecuador where a departure from this established pattern is observed. In this locality, males accounted for 59.14% of Tabanidae captures. The disruption in capture patterns observed using Malaise traps represents an uncommon feature in the scientific literature and during collections conducted over eight years in Ecuador. Despite the inherent limitations of Malaise traps in capturing male horseflies, it is possible that under specific conditions, such as the presence of optimal aggregation areas for horseflies, Malaise traps may enhance the capture efficiency of males. Additionally, we provide a detailed discussion on the disruption and disparity in capture sex proportions in Tabanidae, commonly reported in the scientific literature. Understanding these aspects of tabanid behavior is essential due to the outbreaks and deaths associated with trypanosomiasis infections in Ecuador.\u003c/p\u003e","manuscriptTitle":"Atypical case of pattern disruption in sex proportions of Tabanidae collections with malaise traps in ecuadorian forests","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-06-13 18:58:16","doi":"10.21203/rs.3.rs-4366284/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Minor revisions","date":"2024-07-12T12:16:08+00:00","index":"","fulltext":""},{"type":"reviewerAgreed","content":"","date":"2024-06-01T12:57:36+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-05-31T06:10:32+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-05-08T08:44:16+00:00","index":"","fulltext":""},{"type":"submitted","content":"Biologia","date":"2024-05-06T13:17:34+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"biologia","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"biol","sideBox":"Learn more about [Biologia](http://link.springer.com/journal/11756)","snPcode":"11756","submissionUrl":"https://www.editorialmanager.com/biol/default2.aspx","title":"Biologia","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"59c6cfb9-2ded-4734-8c95-ee7607796846","owner":[],"postedDate":"June 13th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2024-11-04T16:29:26+00:00","versionOfRecord":{"articleIdentity":"rs-4366284","link":"https://doi.org/10.1007/s11756-024-01819-x","journal":{"identity":"biologia","isVorOnly":false,"title":"Biologia"},"publishedOn":"2024-11-01 16:20:38","publishedOnDateReadable":"November 1st, 2024"},"versionCreatedAt":"2024-06-13 18:58:16","video":"","vorDoi":"10.1007/s11756-024-01819-x","vorDoiUrl":"https://doi.org/10.1007/s11756-024-01819-x","workflowStages":[]},"version":"v1","identity":"rs-4366284","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4366284","identity":"rs-4366284","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}