Mastermind of manipulation: size-mediated host selection and web manipulation by a Darwin wasp

Mastermind of manipulation: size-mediated host selection and web manipulation by a Darwin wasp | Authorea try { document.documentElement.classList.add('js'); } catch (e) { } var _gaq = _gaq || []; _gaq.push(['_setAccount', 'G-8VDV14Y67G']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); Skip to main content Preprints Collections Wiley Open Research IET Open Research Ecological Society of Japan All Collections About About Authorea FAQs Contact Us Quick Search anywhere Search for preprint articles, keywords, etc. Search Search ADVANCED SEARCH SCROLL This is a preprint and has not been peer reviewed. Data may be preliminary. 6 April 2026 V1 Latest version Share on Mastermind of manipulation: size-mediated host selection and web manipulation by a Darwin wasp Authors : Anna Luiza Martins 0000-0003-2079-5093 [email protected] , Diego Pádua , Adelberto Santos , João Vasconcellos Neto , and Yuri Messas 0000-0002-5778-5326 Authors Info & Affiliations https://doi.org/10.22541/au.177545919.91413561/v1 137 views 77 downloads Contents Abstract Information & Authors Metrics & Citations View Options References Figures Tables Media Share Abstract Polysphinctine wasps are exclusively koinobiont ectoparasitoids of spiders and have the unique ability to manipulate the web construction behaviour of their hosts. Most interactions between polysphinctine wasps and spiders are species-specific. However, recent studies have predicted that these associations are not as narrow as previously thought. Therefore, records on the ecology and biology of new interactions are required to confirm this hypothesis. Herein, we report the Darwin wasp Hymenoepimecis pinheirensis manipulating the behaviour of the tetragnathid spider Leucauge argyra in an urban area in southeastern Brazil (Campinas, São Paulo). We monitored a population of L. argyra in 2021-24 and collected data on the biology of the wasp-spider interaction. Of a total of 5.416 spiders, 6.85% (N=376) were parasitised by H. pinheirensis, with a higher frequency of attack in young individuals. Eggs are laid anterodorsally on the spider’s abdomen and hatch after 2-3 days. The larva of H. pinheirensis has three instars and develops on the host over approximately 12 subsequent days. Between the second and third instar, the parasitoid induces the host spider to build a cocoon web with a reduced number of radii (some of them V-shaped), the absence of viscid lines and hub loops, and three-dimensional structures consisting of lines above and below the hub attached to multiple sites on the substrate. Here, we add a second host for H. pinheirensis and a second parasitoid for L. argyra, which helps to elucidate the entangled web of interactions involving polysphinctine wasps and spiders. Mastermind of manipulation: size-mediated host selection and web manipulation by a Darwin wasp Anna Luiza Oliveira Martins 1* , Diego Galvão de Pádua 2 , Adalberto J. Santos 3 , João Vasconcellos-Neto 1 , Yuri Fanchini Messas 1 1 Departamento de Biologia Animal, Instituto de Biologia, Caixa Postal: 6109, Universidade de Campinas - UNICAMP, 13083-970, Campinas, SP, Brazil 2 Laboratorio de Entomología General y Aplicada, Centro de Investigación de Estudios Avanzados del Maule, Vicerrectoría de Investigación y Postgrado, Universidad Católica del Maule - UCM, Avenida San Miguel, 3605, Talca, Chile. 3 Departamento de Zoologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais - UFMG, 31270-901, Belo Horizonte, MG, Brazil * Corresponding author: [email protected] Acknowledgements We were financially supported by Instituto Nacional de Ciência e Tecnologia dos Hymenoptera Parasitoides da Região Sudeste Brasileira (HYMPAR/Sudeste – CNPq/FAPESP/CAPES), CAPES (grant number quota/2021 to ALOM), Fundação de Amparo à Pesquisa do Estado de São Paulo (grant 2024/16609-9), and National Council for Scientific and Technological Development – CNPq (grant number 151959/2024-2 to YFM, 311843/2022-0 to AJS). Conflict of Interest Statement The authors declare there are no conflicts of interest. Author Contributions Anna Luiza O. Martins, João Vasconcellos-Neto and Yuri F. Messas conceived the ideas and designed methodology; Anna Luiza O. Martins, João Vasconcellos-Neto and Yuri F. Messas collected the data. Anna Luiza O. Martins, Diego G. Pádua and Adalberto J. Santos analyzed the data; Anna Luiza O. Martins and Yuri F. Messas led the writing of the manuscript. All authors contributed critically to the drafts and gave final approval for publication. Data availability statement Data sharing not applicable to this article as no dataset were generated or analyzed during the current study. Mastermind of manipulation: size-mediated host selection and web manipulation by a Darwin wasp Abstract. Polysphinctine wasps are exclusively koinobiont ectoparasitoids of spiders and have the unique ability to manipulate the web construction behaviour of their hosts. Most interactions between polysphinctine wasps and spiders are species-specific. However, recent studies have predicted that these associations are not as narrow as previously thought. Therefore, records on the ecology and biology of new interactions are required to confirm this hypothesis. Here, we report the Darwin wasp Hymenoepimecis pinheirensis manipulating the behavior of the tetragnathid spider Leucauge argyra in an urban area in southeastern Brazil (Campinas, São Paulo). We monitored a population of L. argyra in 2021-24 and collected data on the biology of the wasp-spider interaction. Of a total of 5.416 spiders, 6.85% (N=376) were parasitised by H. pinheirensis , with a higher frequency of attack in young individuals. Eggs are laid anterodorsally on the spider’s abdomen and hatch after 2-3 days. The larva of H. pinheirensis has three instars and develops on the host over approximately 12 subsequent days. Between the second and third instar, the parasitoid induces the host spider to build a cocoon web with a reduced number of radii (some of them V-shaped), the absence of viscid lines and hub loops, and three-dimensional structures consisting of lines above and below the hub attached to multiple sites on the substrate. Here, we add a second host for H. pinheirensis and a second parasitoid for L. argyra , which helps to elucidate the entangled web of interactions involving polysphinctine wasps and spiders. Keywords cocoon web, koinobiont, ectoparasitoid, Polysphincta genus group, polysphinctine wasp , behavioral manipulation Introduction Parasitoidism is a specialized form of parasitism in which the immature stage of the parasitoid ultimately kills its host to complete its life cycle and emerge as free-living adults (Godfray 1994; Harvey et al. 2000; Kuris and Lafferty 2000). This strategy occurs most notably in Hymenoptera, Diptera, Coleoptera, and Neuroptera (Askew 1971; Eggleton and Belshaw 1992). Parasitoid insects are therefore abundant components of nearly all terrestrial ecosystems (Godfray, 1994; Takasuka and Broad, 2024). Increasing interest in parasitoids has focused on the ability of some species to manipulate host behaviour (van Dobben 1952; Holmes and Bethel 1972; Behnke and Barnard 1990; Godfray 1994; Moore 1984, 2002; Thomas et al. 2005; Lafferty and Shaw 2013; Hafer 2016; Soghigian et al. 2017). Such manipulation can influence key ecological processes, such as energy flow in ecosystems and host population dynamics (Lefèvre et al. 2008). For example, fish parasitoids can alter the activity patterns and foraging location of their hosts, increasing their susceptibility to predators (Barber et al. 2000). Wasps of the Polysphincta genus group (or polysphinctine wasps) constitute a monophyletic lineage within the tribe Ephialtini (Ichneumonidae, Pimplinae) (Gauld and Dubois 2006; Quicke et al. 2009; Matsumoto 2016) comprising exclusively koinobiont ectoparasitoids of spiders (Gauld and Dubois 2006). The natural history of polysphinctine wasps is relatively uniform (see review by (Gonzaga et al., 2017; Takasuka and Broad, 2024). After attacking a spider, the female wasp temporarily paralyzes the host and externally oviposits an egg, usually on the abdomen. The spiders then recover and resume their normal life cycle. After hatching, the larvae perforate the cuticle of the host and feed on the spider’s hemolymph, developing within a few days until they are ready to undergo the final molt, subsequently killing the spider (Gonzaga et al. 2017; Eberhard and Gonzaga 2019; Takasuka and Broad 2024). Darwin wasps are reported as species that can manipulate the web-building behavior of their hosts through the release of ecdysteroids, inducing spiders to construct modified structures known as cocoon webs, which in some cases resemble spider moulting webs (Matsumoto 2009; Gonzaga et al. 2010; Takasuka et al. 2015; Kloss et al. 2016, 2022; Eberhard and Gonzaga 2019; Cifuentes-Vargas et al., 2025). These modified webs probably protect the parasitoid cocoon, increasing wasp survival (Matsumoto 2009; Gonzaga et al. 2010; Kloss et al. 2017; Korenko et al. 2022). The first detailed descriptions of web modification induced by a polysphinctine wasp (Eberhard 2000a, 2000b, 2001) stimulated subsequent research focused on investigating the ecology, taxonomy, and evolution of behavioural manipulation in arthropods. Thus, altered host behavior can be considered as an ‘extended phenotype’ of the parasite and can therefore be considered as adaptive behavior manipulation (Dawkins 1982; Poulin 2010; Delazari et al. 2024). Polysphinctine wasps are known to parasitize spiders of ten families: Agelenidae, Cheiracanthiidae, Clubionidae, Dictynidae, Salticidae, Titanoecidae, Araneidae, Linyphiidae, Tetragnathidae, and Theridiidae (Takasuka and Broad 2024). The genus Hymenoepimecis Viereck, 1912 comprises Neotropical polysphinctine wasps that typically establish narrow species-specific interactions with orb-weaving spiders. Hosts include species of the Tetragnathidae genus Leucauge (Gauld 1991; Eberhard 2000a; Eberhard 2001, 2013; Sobczak et al. 2009; Pádua et al. 2016; Kloss et al. 2022) and several Araneidae genera: Araneus (Gonzaga and Sobczak 2007; Sobczak 2012; Sobczak et al. 2012, 2014), Cyrtophora (Gauld 2000; Gonzaga et al. 2022), Manogea (Sobczak et al. 2009), Mecynogea (Messas et al. 2017), and Trichonephila (Fincke et al. 1990; Gauld 1991, 2000; Gonzaga et al. 2010). At least 13 of the 29 valid species of Hymenoepimecis parasites subadult and adult orb-weaving species, inducing a diversity of cocoon web architectures ranging from simple two-dimensional to complex three-dimensional tangles of nonsticky threads (summarized in Pádua et al. 2016; Eberhard and Gonzaga 2019). Although it is suggested that each polysphinctine wasp species attacks one or a few related spider species (Gauld et al. 1998; Hanson and Gauld 2006; Barrantes et al. 2007), host range expansion may confer ecological advantages, such as reduced intraspecific competition and lower dependence on temporal fluctuation in specific host availability (Gonzaga et al. 2024). Currently, only four Hymenoepimecis -spider interactions are known to be not species specific. Two parasitoid wasps attack congeneric spiders: Hymenoepimecis veranii Loffredo & Penteado-Dias, 2009 on Araneus omnicolor (Keyserling, 1893) and Araneus orgaos Levi, 1991 (Gonzaga and Sobczak 2007; Sobczak et al. 2014); and Hymenoepimecis heidyae Gauld, 1991 on Kapogea cyrtophoroides (F. O. Pickard-Cambridge, 1904) and Kapogea sexnotata (Simon, 1895) (Gauld 2000; Barrantes et al. 2018). The wasp Hymenoepimecis bicolor (Brullé, 1846) parasitizes araneids of different genera: Trichonephila clavipes (Linnaeus, 1767) and Cyrtophora citricola (Forsskål, 1775) (Gonzaga et al. 2010, 2022). On the other hand, Hymenoepimecis japi Sobczak et al. 2009 is the only known species to attack spiders of two distinct families, but with similar natural histories: Leucauge roseosignata Mello-Leito, 1943 (Tetragnathidae) and Mecynogea bigibba Simon, 1903 (Araneidae) (Sobczak et al. 2009; Messas et al. 2017). Based on descriptions of the biology and ecology of spider-polysphinctine interactions, Eberhard and Gonzaga (2019) suggested a series of predictions concerning host selection by polysphinctine wasps and the structure and function of cocoon webs. Such predictions include that (1) host species specificity in the wasps should be rare; (2) spiders with different natural histories manipulated by a single wasp species should construct cocoon webs with designs that differ widely; (3) single spider species attacked by multiple parasitoid species should maintain similar cocoon web designs; (4) the cocoon should resemble the moulting or overwintering webs of the host species; (5) the cocoon web designs should be adjusted appropriately to the natural history of the spider species to provide protection. Such predictions still require testing through increased efforts to record and describe new interactions between spiders and polysphinctine wasps. The specificity of these interactions is likely influenced by factors related to parasitoids, hosts, and environmental context. Regarding the parasitoid, restrictions can include limitations in locating new hosts, behavioural plasticity in response to host defensive variability, as well as specific nutritional requirements (Gonzaga et al. 2024). Hosts, otherwise, may differ in availability (e.g., abundance and size) across environments (Gonzaga et al. 2024). According to optimal foraging theory (MacArthur and Pianka, 1966), interactions are shaped by trade-offs between the costs and benefits associated with searching, subduing, and consuming prey. Thus, the nutritional value of the prey represents an important component of foraging strategies. Therefore, the selection of the host by the parasitoid is essential to ensure successful immobilization and oviposition. Polysphinctine wasps are consequently expected to select hosts large enough to provide sufficient resources for larvae development, but small enough to be successfully subdued by the parasitoid (Sobczak et al. 2023), a pattern that has been reported in several studies (Fincke et al. 1990; Gonzaga and Sobczak 2007; Korenko and Pekár 2011; Gonzaga et al. 2015; Sobczak et al. 2023; Xavier et al. 2024, 2025). For example, Hymenoepimecis pinheirensis Penteado-Dias & Pádua, 2022 females are prone to oviposit mainly on the largest available individuals of Leucauge volupis Keyserling, 1893 (Gonzaga et al. 2015; Kloss et al. 2022), but the optimal host size may depend on the spider’s growth potential and the size range of the parasitoid species (Xavier et al. 2024). Here we report a new host-parasitoid interaction involving Leucauge argyra (Walckenaer, 1841) parasitised by H. pinheirensis . Additionally, we describe web modifications induced by the parasitoid and host selection patterns. We hypothesized that polysphinctine wasps selectively attack certain spider hosts based on host biomass. Consequently, we predict that wasps attack spiders of intermediate size more frequently, as they are the most abundant in the population. Furthermore, we hypothesized that behavioural manipulation induces cocoon webs resembling spider moulting webs, thus improving parasitoid survival. Material and methods Study species Leucauge argyra is a diurnal orb-web tetragnathid spider with a known distribution from the USA to Brazil (World Spider Catalog 2026), that usually weaves horizontal webs in shrubby vegetation. The species also exhibits a sexual size dimorphism, with females generally larger than males. The report of L. argyra as host of Hymenoepimecis argyraphaga Gauld, 2000 in Costa Rica, was the first case of behavioral manipulation involving spiders and polysphinctine wasps (Eberhard, 2000a). The second instar larvae of H. argyraphaga induce the spider to construct a full modified cocoon web, which differs structurally from normal webs by the reduced number of radial lines and the absence of sticky spirals. After 25 years, that is still the only spider-wasp interaction involving L. argyra as a host. Polysphinctine wasp H. pinheirensis is a recently described species reported as a parasitoid of L. volupis (Kloss et al. 2022). The genus Hymenoepimecis is exclusively Neotropical, with 29 described species, which are mainly parasitoids of spiders of the Araneidae family and Leucauge tetragnathids (Yu et al., 2016; Eberhard and Gonzaga, 2019; Pádua et al., 2022, 2020; Takasuka and Broad, 2024). Study area We developed our research in Parque Ecológico Professor Hermógenes de Freitas Leitão Filho (22º48’43’ ’S, 47º04’19’ ’W, 583 m above sea level), an urban park located close to the University of Campinas, São Paulo, Brazil. Most of our study site (0.10 of 0.13 km 2 ) is occupied by a lagoon, surrounded by a 1.5 km dirt path used for outdoor activities by the local population and by native and exotic vegetation containing trees, shrubs, and grassy stretches. The park is frequently subject to anthropogenic actions, such as pollution, artificial light at night, and routine pruning of shrub vegetation. Despite this, the area has been the site of other ecological studies (see, e.g., D’Angelo et al. 2016) and has high biodiversity. We observed that both the spider and parasitoid wasp populations have remained abundant over the past few years. Therefore, this is a favorable environment for conducting our study. Larval Behavior and Field Observations We conducted monthly diurnal expeditions with visual searches for individuals of L. argyra between May 2021 and May 2024. To assess parasitism frequency, we recorded for each spider found the presence or absence of an egg or wasp larvae on its abdomen. We also recorded the developmental stage of the spiders to verify whether the wasps selected their hosts by size. We followed previous studies (eg, Messas et al. 2014; Souza et al. 2022) by classifying spiders as spiderling (recently emerged = 2nd instar, Fig. 1a), young (3rd – 5th instar, Fig. 1b-d), juvenile (6th – 7th instar, Fig. 1e-f), subadult (secondary sexual characters in formation, Fig. 2a -b) and adult (sclerotized genitalia, Fig. 2c-d) based on the length of the legs and carapace. We photographed normal and cocoon webs in situ and in laboratory conditions using a DSLR camera to describe the web structures before and after behavioural manipulation and to compare them with the molting web. We recorded five variables from the webs in each photograph: (i) length, (ii) width, (iii) radii number, (iv) number of spiral loops, and (v) hub loops. To study the larval development of wasps, we collected parasitized spiders and kept them under laboratory conditions in transparent plastic vials measuring 25 x 12 cm, with cotton balls soaked in water and a protein solution as food resource. We photographed all developmental stages of H. pinheirensis , from the egg to the adult stage, recording the time between instars until adult wasps emerged, in addition to the structural characteristics of the cocoon and parasitoid behavior (eg, cocoon construction, behavioural manipulation, death and host consumption). We deposited wasp voucher specimens in the invertebrates collection of the Instituto Nacional de Pesquisas da Amazônia (curator M. L. Oliveira) and spiders in the arachnid collection of Taxonomic Collections of the Universidade Federal de Minas Gerais (curator A. J. Santos). Statistical analysis We analyzed the photographs of each web using the software ImageJ (Schneider et al. 2012), measuring three web traits: (i) web length, (ii) web width, and (iii) hub loops. To assess ontogenetic changes in web architecture and the effects associated with parasitoid presence, we used generalized linear models (GLMs) fitted for each web trait, performed in software R (R Core Team 2022) using the packages ‘MASS’ (Venables and Ripley 2002), ‘emmeans’ (Lenth and Piaskowski 2025) and ‘ggplot2’ (Wickham 2016). Continuous response variables were analyzed using Gaussian GLMs, while count response variables (e.g., number of radii and spiral loops) were analyzed using negative binomial GLMs. The web category (e.g., normal web across developmental stages, modified web and molting web) was used as a fixed explanatory factor in all models. Post hoc pairwise comparisons were conducted using marginal means, with Tukey adjustments for multiple comparisons. To evaluate the distribution of parasitoidism across host stages, we constructed an interaction matrix in R (R Core Team 2022) with one row for the parasitoid and multiple columns for the host stages (e.g., young, juvenile, subadult, and adult). The relative intensity of parasitoidism was quantified as the proportion of attacks, and we applied Fisher’s exact test to verify whether parasitoidism occurred proportionally to host availability. Selectivity among host instars was assessed using Ivlev’s electivity index (Ei), comparing the proportions of each instar available in the environment (Ivlev 1961). The index ranges from -1 (avoidance) to +1 (total selectivity), with 0 indicating parasitoidism proportional to host availability. We used the package ‘selectapref’ (Richardson 2020) in R (R Core Team 2022). Results Of the 5.417 individuals of L. argyra that we recorded, 6.94% (N=376) were attacked by H. pinheirensis , with a monthly average of 10 ± 10 parasitised spiders. The frequency of parasitism varied drastically throughout the year, increasing during winter and almost reducing to zero in summer. We did not observe spiderlings parasitised during the study period. On the other hand, the frequency of attacks on juveniles was the highest (60,6%), followed by young (21,8%), subadults (14,1%), and adults (3,46%) (Fig. 3a). However, based on spider availability at each stage of development in nature, the frequency of parasitism was statistically higher than expected only for juveniles (p < 0.001 ) and subadults (p < 0.001 ), and lower than expected for young ( p < 0.001 ). We found 209 subadults and 189 adult individuals of L. argyra, of which 158 were males and 210 were females. Therefore, the tertiary sex ratio of the species, ie the proportion of males to females in the population, was not biased, presenting a similar number of male and female individuals (sex ratio - male: female = 1: 1.3). However, parasitoidism was markedly higher in females (N = 58) than in adult males (N = 5). Based on the Ivlev electivity index (Ei), there is a positive selection of juvenile spiders (Ei = 0.469) and subadults (Ei= 0.400). Although juveniles represent only 22% of the population, they account for 60% of attacks, indicating a strong preference by the wasp. On the contrary, the wasp showed avoidance for young spiders (Ei= -0.506) (Fig. 3b). We observed that the wasp hovered above the web for approximately 10 seconds, while the spider was resting at the center. Then, rapidly darts at the host in an abrupt plunge. The parasitoid keeps the spider paralyzed on the web, using its legs and stinging the host. Once the spider is overpowered, the wasp proceeds to lay a single egg anterodorously on the abdomen of the spider (N = 376, Fig. 4a). The hatching of the egg occurs after 2 ± 1.42 days (N= 13). Hymenoepimecis pinheirensis completes its immature development through three larval stages (Fig. 4b – e). The first instar larvae (Fig. 4b) begin to feed on the host hemolymph through a small hole in the host abdomen, and after 4 ± 3.04 days (N= 15), they molt and reach the second instar (Fig. 4c). Approximately 5 ± 3.86 days later (N= 16), the larvae reach the third and final instar (Fig. 4d-e), which differs from the previous ones by the presence of eight dorsal tubercles with several tiny hooks. Then the last instar larvae kill the host, intensify the consumption of hemolymph from the host’s abdomen and cephalothorax, and then discard the drained carcass of the host. The third instar larvae construct the cocoon during the next 3 ± 1.76 days (N= 12, Fig. 4f-g). Construction takes place overnight, starting in the early evening and finishing before the following morning. Initially, the cocoon is yellow, acquiring a yellow-orange coloration in approximately four days (Fig. 4f-g). The adult wasp (Fig. 4h-i) takes an average time of 8 ± 0.78 days (N= 9) to emerge from the cocoon. Usually, the wasps remain on the outer surface of the cocoon for a few minutes before flying away. Prey capture orbwebs of L. argyra are frequently horizontal, converging to a hub with an open hole in the center, with about 13 cm (12.94 ± 5.17) length and 14 cm (13.56 ± 5.32) width, 32 radii (31.72 ± 6.73), 32 spiral loops (31.52 ± 11.40) and 0.2 centimeters in the hub loops (0.18 ± 0.07) (Fig. 5a-b). Across the development stages, the web architecture showed a significant statistical difference. The length and width increased progressively with the growth of the spider (Fig. 6a-b). Although the number of radii increased early and stabilized after the juvenile stage (Fig. 6c), the hub loops increased only in adults (Fig. 6e) and the number of spirals did not differ across ontogeny (Fig. 6d). Between the second and third instars, the parasitoid induces the host spider to build a cocoon web at the same site and as a modification of the normal web (Fig. 5c-d). These modified webs present a reduced number of radii (12.67 ± 1.15), some V-shaped threads, the complete absence of viscid lines and hub loops, and a three-dimensional structure consisting of lines above and below the hub attached to multiple sites on the substrate and the cocoon hanging in the middle. Cocoon and molting webs differ drastically from prey capture webs. However, the modified web and the molting web did not show statistical differences in structural architecture (p > 0.05), being similar mainly in the significant reduction in the number of radii (Fig. 7c). On the other hand, we did not find significant differences in the length, width, and spiral loops (Fig. 7a, b, and d). Nevertheless, it is important to mention that both the molting and cocoon webs do not have spiral loops, and the statistical difference was not detected as a result of the structure of the data. Discussion Here, we describe a new host-parasitoid interaction, adding L. argyra as a novel host to H. pinheirensis (which also attacks L. volupis in southeastern Brazil) and a novel parasitoid to L. argyra (also attacked by H. argyraphaga in Costa Rica). Together with previous records of H. pinheirensis parasitizing L. volupis (Kloss et al. 2022), our findings reinforce that spiders of the genus Leucauge are the main hosts of the genus Hymenoepimecis, although this wasp genus can also be associated with other orb-weaver spiders (Araneidae), representing a host preference relatively stable at the genus level (Takasuka and Broad 2024). Our findings corroborate the hypothesis proposed by Eberhard and Gonzaga (2019) that such interactions are less species-specific than previously thought and constitute a complex web of interactions. Rather than strict species-level specialization, host use appears constrained by shared ecological and behavioural traits, such as web architecture, microhabitat, and growth patterns. This form of ecological specialization can facilitate host switching among closely related or functionally similar spiders, potentially increasing parasitoid persistence under fluctuating host availability. The absence of parasitism in spiderlings, despite their high abundance in the population, suggests that early instars do not provide sufficient resources for successful larval development. On the contrary, juvenile and subadult spiders were attacked at higher frequencies than expected based on their availability, but lower than expected for small to intermediate-sized spiders (young). These results suggest that, for this interaction, wasps are prone to attack intermediate-sized spiders, consistent with patterns reported in other polysphinctine systems (Fincke et al. 1990; Gonzaga et al. 2015; Sobczak et al. 2023), reflecting a trade-off between host profitability and handling risk. Intermediate-sized spiders likely offer enough biomass to sustain parasitoid development while remaining vulnerable to successful subjugation by the wasp, whereas very small hosts may be nutritionally insufficient and larger hosts may increase attack costs or failure rates (Gonzaga et al. 2010), given that the adult spider is usually larger than the female wasp. It has been reported that the determination of progeny sex may depend on the host size for some hymenopterans (see, e.g., Charnov et al., 1981; Takasuka et al., 2009; Benamú et al. 2020; Sobczak et al. 2023). For example, females of H. bicolor emerge from the larger spiders T. clavipes , while male wasps emerge from the smaller hosts (Sobczak et al. 2023), since males require fewer resources to develop than female wasps (Sobczak et al. 2019). Our results suggest that host selection is shaped by sexual size dimorphism, in which smaller male hosts provide less biomass for parasitoid development. That may reflect a population-level requirement for more female wasp individuals. Such size-mediated host selection aligns with predictions from optimal foraging theory (MacArthur and Pianka, 1966). Selective pressure may also influence the structure of the host population by disproportionately affecting specific stages of development, thereby altering phenology during periods of high parasitism. Our study contrasts with previous findings for H. pinheirensis parasitizing L. volupis , in which females preferentially attacked the largest available individuals in the population (Gonzaga et al. 2015), but also attacked smaller ones, since the entire population of L. volupis was composed of relatively small spiders (Xavier et al. 2024). In populations with a broader size range, as in L. argyra , parasitoids can optimize host choice by targeting intermediate-sized hosts, balancing nutritional gain and handling success. These size selection patterns by the same wasp across different populations reflect a variation in the range of host sizes accessible to the parasitoid, while also capturing differences in host growth potential and size availability in the environment, suggesting that host selection by polysphinctine wasp is context dependent, shaped by local host demography rather than fixed size. Such flexibility can facilitate the expansion of the host range, contributing to the persistence of parasitoid populations under fluctuating environmental conditions. The cocoon web architecture induced in L. argyra by H. pinheirensis closely resembles the modified webs described for L. volupis parasitized by the same wasp species (Kloss et al. 2022), as well as the most common pattern built by Leucauge mariana (Taczanowski, 1881) manipulated by Hymenoepimecis tedfordi Gauld, 1991 (Eberhard 2013). The modified web showed some similarities with webs described by L. argyra (Eberhard 2000a), such as lack of adhesive spirals, a pattern of reinforced radii converging to the center of the web, and lines connected to the vegetation at multiple points. However, the cocoon webs of L. argyra by the influence of H. pinheirensis also showed a tridimensional structure positioned below the hub, similar to the pattern constructed by L. volupis parasitized by H. pinheirensis (Kloss et al. 2022), but still with the open hole in the middle of the web. The cocoon web also presented a similar number of radii with the modified web of L. volupis , but more than what is constructed by L. argyra by the influence of H. argyraphaga (Eberhard, 2000a; Kloss et al., 2022). This indicates that while host phylogeny may constrain the general form of modified webs, parasitoid identity can influence specific architectural features. As congeneric spiders, recurrent similarities in cocoon webs built by Leucauge species support the hypothesis that behavioural manipulation is related to the specific response of Leucauge species to the behavioural manipulation mechanism used by the wasp (Kloss et al. 2022). By inducing ecdysteroid production to manipulate the behaviour of different spiders, it seems that the spider, rather than the wasp, is expected to determine the design of the cocoon web, resulting in a stereotyped modified web structure characteristic of the spider lineage. This interpretation is consistent with the prediction that spiders with similar natural histories manipulated by a single wasp species should produce comparable cocoon web designs (Eberhard and Gonzaga 2019). However, our observation that L. argyra built modified webs different from what was described by the influence of H. argyraphaga suggests that the wasp can determine the web design, challenging the complementary prediction that a single host should exhibit a similar cocoon web architecture regardless of the parasitoid species involved (Eberhard and Gonzaga 2019). The differences between H. pinheirensis and H. argyraphaga suggest that parasitoids may differ in the timing, intensity, or combination of physiological signals to trigger the host response. The strong similarity between cocoon webs and molting webs provides additional evidence that behavioural manipulation by polysphinctine wasps exploits the host’s endogenous molting program. Several studies suggest that web modification in spiders is caused by an anachronic activation of the ecdysis mechanism, manipulating an innate system of spiders (Takasuka et al. 2015; Kloss et al. 2017; Eberhard and Gonzaga 2019). From a functional perspective, molting represents a highly vulnerable phase in the life cycle of the spider, during which the construction of a protective web likely reduces the exposure to predators and environmental stress. By inducing a similar structure prior to host death, the parasitoid effectively co-opts an adaptive spider response for its own protection. This convergence in function supports the view that cocoon web construction enhances parasitoid survival and represents an adaptive outcome of behavioural manipulation (Dawkins 1982; Eberhard 2009; Matsumoto 2009; Poulin 2010; Korenko et al. 2022). Our results indicate that polysphinctine wasps may exert substantial pressure on spider populations in anthropized environments, with parasitism rates reaching high levels during specific periods of the year. The temporal peaks in parasitism coincided with an increased availability of juvenile hosts, suggesting a possible phenological adjustment between L. argyra and H. pinheirensis populations. This synchrony may enhance parasitoid reproductive success by aligning peak host vulnerability with periods of high parasitoid activity. Similar seasonal dynamics have been reported in other host-parasitoid systems and may play an important role in regulating host population structure over time (see, e.g., Barrantes et al., 2007). These findings highlight the importance of incorporating temporal perspectives into studies of spider-parasitoid interactions, particularly in disturbed or urbanized habitats where environmental fluctuations can strongly influence population dynamics. References Askew, R.R., 1971. Parasitic insects. Heinemann Educational Books, London, UK. Barber, I., Hoare, D., Krause, J., 2000. Effects of parasites on fish behaviour: a review and evolutionary perspective. Reviews in Fish Biology and Fisheries 10, 131–165. https://doi.org/10.1023/A:1016658224470 Barrantes, G., G. Eberhard, W., Ling Wen, J., 2007. Seasonal patterns of parasitism of the tropical spiders Theridion evexum (Araneae, Theridiidae) and Allocyclosa bifurca (Araneae, Araneidae) by the wasps Zatypota petronae and Polysphincta gutfreundi (Hymenoptera, Ichneumonidae). RBT. https://doi.org/10.15517/rbt.v56i2.5621 Barrantes, G., Segura-Hernández, L., Solano-Brenes, D., Hanson, P., 2018. When a little is enough: cocoon web of Kapogea cyrtophoroides (Araneae: Araneidae) induced by Hymenoepimecis heidyae (Ichneumonidae: Pimplinae). Arachnologische Mitteilungen 55, 30–35. https://doi.org/10.30963/aramit5505 Behnke, J.M., Barnard, C.J. (Eds.), 1990. Parasitism and host behaviour. Taylor & Francis Group, London, United Kingdom. Benamú, M., García, L.F., Viera, C., Lacava, M., Korenko, S., 2020. Koinobint life style of the spider wasp Minagenia (Hymenoptera, Pompilidae) and its consequences for host selection and sex allocation. Zoology 140, 125797. https://doi.org/10.1016/j.zool.2020.125797 Charnov, E.L., Los-den Hartogh, R.L., Jones, W.T., Van Den Assem, J., 1981. Sex ratio evolution in a variable environment. Nature 289, 27–33. https://doi.org/10.1038/289027a0 Cifuentes-Vargas, E.T., De Pádua, D.G., Santos, A.J., Damasceno, A., Kloss, T.G., 2025. Behavioral manipulation in a cobweb spider: insights from comparisons between parasitized and healthy spiders. J Ethol 43, 171–181. https://doi.org/10.1007/s10164-025-00848-6 D’Angelo, G.B., Nagai, M.E., Sazima, I., 2016. Relações alimentares de aves com capivaras (Hydrochoerus hydrochaeris) em parque urbano no Sudeste do Brasil. Pap. Avulsos Zool. 56, 33. https://doi.org/10.11606/0031-1049.2016.56.04 Dawkins, R., 1982. The extended phenotype. Oxford Univerty Press. Delazari, Í.M., Mendes-Pereira, T., Saltamachia, S.J., Kloss, T.G., 2024. Masters of puppets: could the ecdysteroid route be a common pathway for behavioural manipulation in spiders by different parasites? Biological Journal of the Linnean Society 144, blaf001. https://doi.org/10.1093/biolinnean/blaf001 Eberhard, W.G., 2013. The Polysphinctine Wasps Acrotaphus tibialis, Eruga ca. gutfreundi , and Hymenoepimecis tedfordi (Hymenoptera, Ichneumonidae, Pimplinae) Induce Their Host Spiders to Build Modified Webs. Annals of the Entomological Society of America 106, 652–660. https://doi.org/10.1603/AN12147 Eberhard, W.G., 2009. Recovery of spiders from the effects of parasitic wasps: implications for fine-tuned mechanisms of manipulation. Animal Behaviour 79, 375–383. https://doi.org/10.1016/j.anbehav.2009.10.033 Eberhard, W.G., 2001. UNDER THE INFLUENCE: WEBS AND BUILDING BEHAVIOR OF PLESIOMETA ARGYRA (ARANEAE, TETRAGNATHIDAE) WHEN PARASITIZED BY HYMENOEPIMECIS ARGYRAPHAGA (HYMENOPTERA, ICHNEUMONIDAE). Journal of Arachnology 29, 354–366. https://doi.org/10.1636/0161-8202(2001)029%255B0354:UTIWAB%255D2.0.CO;2 Eberhard, William G., 2000a. Spider manipulation by a wasp larva. Nature 406, 255–256. https://doi.org/10.1038/35018636 Eberhard, William G, 2000b. The natural history and behavior of Hymenoepimesis argyraphaga (Hymenoptera: Ichneumonidae) a parasitoid of Plesiometa argyra (Araneae: Tetragnathidae). Journal of Hymenoptera Research 9, 220–240. Eberhard, W.G., Gonzaga, M.O., 2019. Evidence that Polysphincta-group wasps (Hymenoptera: Ichneumonidae) use ecdysteroids to manipulate the web-construction behaviour of their spider hosts. Biological Journal of the Linnean Society 127, 429–471. https://doi.org/10.1093/biolinnean/blz044 Eggleton, P., Belshaw, R., 1992. Insect parasitoids: an evolutionary overview. Philos Trans R Soc Lond B Biol Sci 337, 1–20. Fincke, O., Higgins, L., Rojas, E., 1990. Parasitism of Nephila clavipes (Araneae, Tetragnathidae) by an ichneumonid (Hymenoptera, Polysphintini) in Panama. Journal of Arachnology 18, 321–329. Gauld, I.D., 2000. The re-definition of pimpline genus Hymenoepimecis (Hymenoptera: Ichneumonidae) with a description of a plesiomorphic new Costa Rican species. Journal of Hymenoptera Research 9, 213–219. Gauld, I.D., 1991. The Ichneumonidae of Costa Rica, Memoirs of the Entomological Insitute. Gauld, I.D., Dubois, J., 2006. Phylogeny of the Polysphincta group of genera (Hymenoptera: Ichneumonidae; Pimplinae): a taxonomic revision of spider ectoparasitoids. Systematic Entomology 31, 529–564. https://doi.org/10.1111/j.1365-3113.2006.00334.x Gauld, I.D., Hanson, P.E., Ugalde, J.A.G., 1998. Guía de los Pimplinae de Costa Rica (Hymenoptera: Ichneumonidae), 46 (Supl. 1). Rev. Biolo. Trop. Godfray, H.C.J., 1994. Parasitoids: Behavioral and Evolutionary Ecology. Princeton University Press, Princeton, U.S.A. Gonzaga, M.O., Kloss, T.G., Sobczak, J.F., 2017. Host Behavioural Manipulation of Spiders by Ichneumonid Wasps, in: Viera, C., Gonzaga, M.O. (Eds.), Behaviour and Ecology of Spiders. Springer International Publishing, Cham, pp. 417–437. https://doi.org/10.1007/978-3-319-65717-2_16 Gonzaga, M.O., Pádua, D.G., Quero, A., 2022. Inclusion of an alien species in the host range of the Neotropical parasitoid Hymenoepimecis bicolor (Brullé, 1846) (Hymenoptera, Ichneumonidae). JHR 89, 9–18. https://doi.org/10.3897/jhr.89.76620 Gonzaga, M.O., Rafael R. Moura, Alexander Gaione-Costa, Thiago G. Kloss, 2024. Patterns of host specificity in interactions involving behavioral manipulation of spiders by Darwin wasps, in: Advances in the Study of Behavior. Elsevier, pp. 89–154. https://doi.org/10.1016/bs.asb.2024.02.002 Gonzaga, M.O., Rios Moura, R., Teixeira Pêgo, P., Lee Bang, D., Meira, F.A., 2015. Changes to web architecture of Leucauge volupis (Araneae: Tetragnathidae) induced by the parasitoid Hymenoepimecis jordanensis (Hymenoptera: Ichneumonidae). Behav 152, 181–193. https://doi.org/10.1163/1568539X-00003238 Gonzaga, M.O., Sobczak, J.F., 2007. Parasitoid-induced mortality of Araneus omnicolor (Araneae, Araneidae) by Hymenoepimecis sp. (Hymenoptera, Ichneumonidae) in southeastern Brazil. Naturwissenschaften 94, 223–227. https://doi.org/10.1007/s00114-006-0177-z Gonzaga, M.O., Sobczak, J.F., Penteado-Dias, A.M., Eberhard, W.G., 2010. Modification of Nephila clavipes (Araneae Nephilidae) webs induced by the parasitoids Hymenoepimecis bicolor and H. robertsae (Hymenoptera Ichneumonidae). Ethology Ecology & Evolution 22, 151–165. https://doi.org/10.1080/03949371003707836 Hafer, N., 2016. Conflicts over host manipulation between different parasites and pathogens: Investigating the ecological and medical consequences. BioEssays 38, 1027–1037. https://doi.org/10.1002/bies.201600060 Hanson, P.E., Gauld, I.D., 2006. Hymenoptera de la Región Neotropical. American Entomological Institute, Gainesville, Florida, USA. Harvey, J.A., Kadash, K., Strand, M.R., 2000. Differences in larval feeding behavior correlate with altered developmental strategies in two parasitic wasps: Implications for the size-fitness hypothesis. Oikos 88, 621–629. Holmes, J.C., Bethel, W.M., 1972. Modificiation of intermediate host beahviour by parasites, in: Behavioural Aspects of Parasite Transmission. Academic Press. Ivlev, V.S., 1961. Experimental Ecology of the Feeding of Fish. Yale University Press, New York. Kloss, T.G., De Pádua, D.G., De Almeida, S.D.S., Penteado-Dias, A.M., Mendes-Pereira, T., Sobczak, J.F., Lacerda, F.G., Gonzaga, M.O., 2022. A New Darwin Wasp (Hymenoptera: Ichneumonidae) and New Records of Behavioral Manipulation of the Host Spider Leucauge volupis (Araneae: Tetragnathidae). Neotrop Entomol 51, 821–829. https://doi.org/10.1007/s13744-022-00991-6 Kloss, T.G., Gonzaga, M.O., De Oliveira, L.L., Sperber, C.F., 2017. Proximate mechanism of behavioral manipulation of an orb-weaver spider host by a parasitoid wasp. PLoS ONE 12, e0171336. https://doi.org/10.1371/journal.pone.0171336 Kloss, T.G., Gonzaga, M.O., Roxinol, J.A.M., Sperber, C.F., 2016. Host behavioural manipulation of two orb-weaver spiders by parasitoid wasps. Animal Behaviour 111, 289–296. https://doi.org/10.1016/j.anbehav.2015.11.001 Korenko, S., Pekár, S., 2011. A Parasitoid Wasp Induces Overwintering Behaviour in Its Spider Host. PLoS ONE 6, e24628. https://doi.org/10.1371/journal.pone.0024628 Korenko, S., Sýkora, J., Kostro-Ambroziak, A., Pekár, S., 2022. Two lines of defense in the pupas of ichneumonid wasp parasitoids associated with spider hosts. Front. Ecol. Evol. 10, 1061700. https://doi.org/10.3389/fevo.2022.1061700 Kuris, A.M., Lafferty, K.D., 2000. Parasite-host modeling meets reality: Adaptive peaks and their ecological attributes, in: Evolutionary Biology of Host-Parasite Relationships: Theory Meets Reality. Elsevier Science, Amsterdam, pp. 9–26. Lafferty, K.D., Shaw, J.C., 2013. Comparing mechanisms of host manipulation across host and parasite taxa. Journal of Experimental Biology 216, 56–66. https://doi.org/10.1242/jeb.073668 Lefèvre, T., Roche, B., Poulin, R., Hurd, H., Renaud, F., Thomas, F., 2008. Exploiting host compensatory responses: the ‘must’ of manipulation? Trends in Parasitology 24, 435–439. https://doi.org/10.1016/j.pt.2008.06.006 Lenth, R.V., Piaskowski, J., 2025. _emmeans: Estimated Marginal Means, aka Least-Squares Means_. MacArthur, R.H., Pianka, E.R., 1966. On Optimal Use of a Patchy Environment. The American Naturalist 100, 603–609. Matsumoto, R., 2016. Molecular phylogeny and systematics of the Polysphincta group of genera (Hymenoptera, Ichneumonidae, Pimplinae). Systematic Entomology 41, 854–864. https://doi.org/10.1111/syen.12196 Matsumoto, R., 2009. “Veils” Against Predators: Modified Web Structure of a Host Spider Induced by an Ichneumonid Parasitoid, Brachyzapus nikkoensis (Uchida) (Hymenoptera). J Insect Behav 22, 39–48. https://doi.org/10.1007/s10905-008-9152-1 Messas, Y.F., Sobczak, J.F., Vasconcellos-Neto, J., 2017. An alternative host of Hymenoepimecis japi (Hymenoptera, Ichneumonidae) on a novel family (Araneae, Araneidae), with notes on behavioral manipulations. JHR 60, 111–118. https://doi.org/10.3897/jhr.60.14817 Messas, Y.F., Souza, H.S., Gonzaga, M.O., Vasconcellos-Neto, J., 2014. Spatial distribution and substrate selection by the orb-weaver spider Eustala perfida Mello-Leitão, 1947 (Araneae: Araneidae). Journal of Natural History 48, 2645–2660. https://doi.org/10.1080/00222933.2014.909067 Moore, J., 2002. Parasites and the Behavior of Animals. Oxford Univerty Press. Moore, J., 1984. Parasites that Change the Behavior of their Host. Sci Am 250, 108–115. https://doi.org/10.1038/scientificamerican0584-108 Pádua, D.G., Kloss, T.G., Tavares, M.T., Santos, B.F., Araujo, R.O., Schoeninger, K., Sobczak, J.F., Gonzaga, M.O., 2022. Hyperparasitoids of polysphinctine Darwin wasps (Hymenoptera: Ichneumonidae) in South America. Austral Entomology 61, 170–186. https://doi.org/10.1111/aen.12593 Pádua, D.G., Salvatierra, L., Sobczak, J.F., Oliveira, M., 2016. Parasitism of Hymenoepimecis manauara Pádua & Oliveira (Hymenoptera: Ichneumonidae: Pimplinae) on Leucauge henryi Mello-Leitão (Araneae: Tetragnathidae) in Brazilian Amazonian. Biodiversity Data Journal 4. Pádua, D.G.D., Sääksjärvi, I.E., Monteiro, R.F., Oliveira, M.L.D., 2020. Seven new species of spider-attacking Hymenoepimecis Viereck (Hymenoptera, Ichneumonidae, Pimplinae) from Ecuador, French Guiana, and Peru, with an identification key to the world species. ZK 935, 57–92. https://doi.org/10.3897/zookeys.935.50492 Poulin, R., 2010. Parasite Manipulation of Host Behavior, in: Advances in the Study of Behavior. Elsevier, pp. 151–186. https://doi.org/10.1016/S0065-3454(10)41005-0 Quicke, D.L.J., Laurenne, N.M., Fitton, M.G., Broad, G.R., 2009. A thousand and one wasps: a 28S rDNA and morphological phylogeny of the Ichneumonidae (Insecta: Hymenoptera) with an investigation into alignment parameter space and elision. Journal of Natural History 43, 1305–1421. https://doi.org/10.1080/00222930902807783 R Core Team, 2022. R: A Language and Environment for Statistical Computing. Richardson, J., 2020. selectapref: Analysis of Field and Laboratory Foraging. Schneider, C.A., Rasband, W.S., Eliceiri, K.W., 2012. NIH Image to ImageJ: 25 years of image analysis. Nat Methods 9, 671–675. https://doi.org/10.1038/nmeth.2089 Sobczak, J., Loffredo, A., Penteado-Dias, A., 2012. Parasitism on Araneus venatrix (Koch, 1838) (Araneae: Araneidae) by Hymenoepimecis silvanae Loffredo and Penteado-Dias, 2009 (Ichneumonidae, Pimplinae) with description of male of the wasp. Braz. J. Biol. 72, 221–223. https://doi.org/10.1590/S1519-69842012000100028 Sobczak, Jf., 2012. Description of the male Hymenoepimecis japi Sobczak et al. 2009 (Hymenoptera, Ichneumonidae) parasitoid of Leucauge roseosignata Mello-Leitão 1943 (Araneae: Tetragnathidae). Braz. J. Biol. 72, 945–947. https://doi.org/10.1590/S1519-69842012000500023 Sobczak, J.F., Loffredo, A.P.S., Penteado-Dias, A.M., Gonzaga, M.O., 2009. Two new species of Hymenoepimecis (Hymenoptera: Ichneumonidae: Pimplinae) with notes on their spider hosts and behaviour manipulation. Journal of Natural History 43, 2691–2699. https://doi.org/10.1080/00222930903244010 Sobczak, J.F., Loffredo, A.P.S., Penteado-Dias, A.M., Messas, Y.F., Pádua, D.G., 2019. Description of the male of Hymenoepimecis bicolor (Brullé, 1846) (Hymenoptera, Ichneumonidae, Pimplinae). Braz. J. Biol. 79, 154–157. https://doi.org/10.1590/1519-6984.178889 Sobczak, J.F., Sobczak, J.C.M.S.M., Messas, Y.F., Souza, H.D.S., Vasconcellos-Neto, J., 2014. A New Record of a Host-Parasitoid Interaction: Hymenoepimecis veranii Lofredo & Penteado-Dias, 2009 (Hymenoptera: Ichneumonidae) Parasitizing Araneus orgaos Levi, 1991 (Araneae: Araneidae). J Insect Behav 27, 753–758. https://doi.org/10.1007/s10905-014-9467-z Sobczak, J.F., Xavier, G.M., Gonzaga, M.O., Penteado‐Dias, A.M., 2023. Host size selection and progeny sex determination in Hymenoepimecis bicolor (Hymenoptera, Ichneumonidae, Pimplinae). Ethology 129, 280–287. https://doi.org/10.1111/eth.13365 Soghigian, J., Valsdottir, L.R., Livdahl, T.P., 2017. A parasite’s modification of host behavior reduces predation on its host. Ecology and Evolution 7, 1453–1461. https://doi.org/10.1002/ece3.2748 Souza, H., Messas, Y.F., Gonzaga, M.O., Vasconcellos-Neto, J., 2022. Population ecology of the orb-weaver spider Eustala taquara (Keyserling) (Araneidae). Journal of Natural History 56, 1045–1061. https://doi.org/10.1080/00222933.2022.2098071 Takasuka, K., Broad, G.R., 2024. A bionomic overview of spider parasitoids and pseudo-parasitoids of the ichneumonid wasp subfamily Pimplinae. Contrib. Zool. 93, 1–106. https://doi.org/10.1163/18759866-bja10053 Takasuka, K., Matsumoto, R., Ohbayashi, N., 2009. Oviposition behavior of Zatypota albicoxa (Hymenoptera, Ichneumonidae), an ectoparasitoid of Achaearanea tepidariorum (Araneae, Theridiidae). Entomological Science 12, 232–237. https://doi.org/10.1111/j.1479-8298.2009.00338.x Takasuka, K., Yasui, T., Ishigami, T., Nakata, K., Matsumoto, R., Ikeda, K., Maeto, K., 2015. Host manipulation by an ichneumonid spider ectoparasitoid that takes advantage of preprogrammed web-building behaviour for its cocoon protection. Journal of Experimental Biology 218, 2326–2332. https://doi.org/10.1242/jeb.122739 Thomas, F., Adamo, S., Moore, J., 2005. Parasitic manipulation: where are we and where should we go? Behavioural Processes 68, 185–199. https://doi.org/10.1016/j.beproc.2004.06.010 van Dobben, W.H., 1952. The food of the cormorant in the Netherlands. Ardea 40, 1–63. Venables, W.N., Ripley, B.D., 2002. Modern applied statistics with S, 4th ed. ed, Statistics and computing. Springer, New York. Wickham, H., 2016. ggplot2: Elegant Graphics for Data Analysis, Second edition. ed, Use R! Springer international publishing, Cham. World Spider Catalog. Version 27. Natural History Museum Bern, online at http://wsc.nmbe.ch. doi: 10.24436/2 Xavier, G.M., Gonzaga, M.O., De Castro, V.C., Silva, W.D., Valentim, A.M., Rios Moura, R., 2024. Effects of host size on progeny sex and survivorship of Hymenoepimecis pinheirensis . Behavioral Ecology 35, arae068. https://doi.org/10.1093/beheco/arae068 Xavier, G.M., Moura, R.R., Penteado‐Dias, A.M., Gonzaga, M.O., 2025. Host selection and cocoon web variation induced by the parasitoid wasp Acrotaphus chedelae . Journal of Zoology 327, 39–48. https://doi.org/10.1111/jzo.70034 Yu, D.S., van Achterberg, C., Horstmann, K. World Ichneumonoidea 2015: Taxonomy, Biology, Morphology and Distribution.Taxapad 2016: database on flash-drive Figure 2. Developmental stage classification of the spider Leucauge argyra. Classified as subadult as (a) female subadult and (b) male subadult; and adult as (c) female adult and (d) male adult. Figure 6 Ontogenetic variation in web architecture of the spider Leucauge argyra. Points represent individual observations, circles and error bars indicate means ± standard error. Different letters denote significant differences among groups based on post-hoc comparisons of estimated marginal means (α = 0.05). Groups sharing the same letter aren’t statistically different. Figure 7 Functional variation in web architecture of the spider Leucauge argyra, comparing the normal orb web of a juvenile, a moult web and a cocoon web induced by the wasp Hymenoepimecis pinheirensis. Points represent individual observations, circles and error bars indicate means ± standard error. Different letters denote significant differences among groups based on post-hoc comparisons of estimated marginal means (α = 0.05). Groups sharing the same letter aren’t statistically different. Information & Authors Information Version history V1 Version 1 06 April 2026 Copyright This work is licensed under a Non Exclusive No Reuse License. Keywords behavioral ecology invertebrate natural history terrestrial Authors Affiliations Anna Luiza Martins 0000-0003-2079-5093 [email protected] Universidade Estadual de Campinas View all articles by this author Diego Pádua Universidad Católica del Maule View all articles by this author Adelberto Santos Universidade Federal de Minas Gerais View all articles by this author João Vasconcellos Neto UNICAMP View all articles by this author Yuri Messas 0000-0002-5778-5326 University of Campinas Institute of Biology View all articles by this author Metrics & Citations Metrics Article Usage 137 views 77 downloads .FvxKWukQNSOunydq8rnd { width: 100px; } Citations Download citation Anna Luiza Martins, Diego Pádua, Adelberto Santos, et al. Mastermind of manipulation: size-mediated host selection and web manipulation by a Darwin wasp. Authorea . 06 April 2026. DOI: https://doi.org/10.22541/au.177545919.91413561/v1 If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download. For more information or tips please see 'Downloading to a citation manager' in the Help menu . Format Please select one from the list RIS (ProCite, Reference Manager) EndNote BibTex Medlars RefWorks Direct import Tips for downloading citations document.getElementById('citMgrHelpLink').addEventListener('click', function() { popupHelp(this.href); return false; }); $(".js__slcInclude").on("change", function(e){ if ($(this).val() == 'refworks') $('#direct').prop("checked", false); $('#direct').prop("disabled", ($(this).val() == 'refworks')); }); View Options View options PDF View PDF Figures Tables Media Share Share Share article link Copy Link Copied! Copying failed. Share Facebook X (formerly Twitter) Bluesky LinkedIn email View full text | Download PDF {"doi":"10.22541/au.177545919.91413561/v1","type":"Article"} Now Reading: Share Figures Tables Close figure viewer Back to article Figure title goes here Change zoom level Go to figure location within the article Download figure Toggle share panel Toggle share panel Share Toggle information panel Toggle information panel Go to previous graphic Go to next graphic Go to previous table Go to next table All figures All tables View all material View all material xrefBack.goTo xrefBack.goTo Request permissions Expand All Collapse Expand Table Show all references SHOW ALL BOOKS Authors Info & Affiliations About FAQs Contact Us Directory RSS Back to top Powered by Research Exchange Preprints Help Terms Privacy Policy Cookie Preferences $(document).ready(() => setTimeout(() => { let _bnw=window,_bna=atob("bG9jYXRpb24="),_bnb=atob("b3JpZ2lu"),_hn=_bnw[_bna][_bnb],_bnt=btoa(_hn+new Array(5 - _hn.length % 4).join(" ")); $.get("/resource/lodash?t="+_bnt); },4000)); (function(){function c(){var b=a.contentDocument||a.contentWindow.document;if(b){var d=b.createElement('script');d.innerHTML="window.__CF$cv$params={r:'9fe0d8743c9a58f4',t:'MTc3OTE3MDA1MQ=='};var a=document.createElement('script');a.src='/cdn-cgi/challenge-platform/scripts/jsd/main.js';document.getElementsByTagName('head')[0].appendChild(a);";b.getElementsByTagName('head')[0].appendChild(d)}}if(document.body){var a=document.createElement('iframe');a.height=1;a.width=1;a.style.position='absolute';a.style.top=0;a.style.left=0;a.style.border='none';a.style.visibility='hidden';document.body.appendChild(a);if('loading'!==document.readyState)c();else if(window.addEventListener)document.addEventListener('DOMContentLoaded',c);else{var e=document.onreadystatechange||function(){};document.onreadystatechange=function(b){e(b);'loading'!==document.readyState&&(document.onreadystatechange=e,c())}}}})();