Honey, what's for dinner? Dietary overlap and size dimorphism between female and male Joro spiders (Trichonephila clavata)

Authors: GRABARCZYK, ERIN - Valdosta State University; Tillman, Patricia; QUEREJETA, MARINA - Universite De Tours; SCHMIDT, JASON - University Of Georgia

Submitted to: Integrative Zoology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/17/2024
Publication Date: 1/15/2025
Citation: Grabarczyk, E.E., Tillman, P.G., Querejeta, M., Schmidt, J.M. 2025. Honey, what's for dinner? Dietary overlap and size dimorphism between female and male Joro spiders (Trichonephila clavata). Integrative Zoology. 0:1-10. https://doi.org/10.1111/1749-4877.12947.
DOI: https://doi.org/10.1111/1749-4877.12947

Interpretive Summary: The Joro spider is an introduced species that was first discovered in the United States in 2014. Female Joro spiders are large, brightly colored, and build massive, golden webs to capture prey. For many web-building spiders, reproductive success increases with body size, which in turn, is related to diet. Therefore, we tested whether the Joro spider dietary patterns are specific to sex of adults and related to body size and condition. We combined size analyses and diet composition via DNA analyses to characterize male and female Joro spider diets from 60 webs at 25 locations. Female Joro spiders were larger than males and their diets were more diverse. While male Joro spiders consumed the same prey taxa as females, greater than 50 additional types of prey were detected in female diets. As male body size increased, diet diversity and body condition decreased, suggesting a potential trade-off between time spent foraging versus active defense of their position on the web. Combined, Joro spiders show sex-specific dietary patterns, and males appear to have less access to the diverse food captured in female webs.

Technical Abstract: Selection on body size tends to favor larger males that outcompete smaller males to mate with females, and larger, more fecund females. For many web-building spiders in the Nephilidae family, reproductive success increases with body size, which in turn, is related to diet. The diet of female spiders may overlap with males who share her web, but diet patterns could depend on size if certain males have better access to prey ensnared in the web. Therefore, we tested whether Joro spider (Trichonephila clavata) dietary patterns are sex-specific and related to body size and condition. We combined morphometric size analysis with molecular gut content analysis via DNA metabarcoding and high-throughput sequencing to characterize male and female Joro spider diets from 60 webs at 25 locations. Female Joro spiders were larger than males and their diets more diverse. While male Joro spiders consumed the same prey taxa as females, greater than 50 additional taxa were detected in female diets, which led to significant dissimilarity in prey composition between sexes. As male body size increased, diet diversity and body condition decreased, suggesting a potential trade-off between time spent foraging versus active defense of their position on the web. Female and male spiders captured from the same web shared prey taxa; however, the proportion of prey overlap was not related to male size. Combined, Joro spiders show sex-specific dietary patterns, and males appear to have less access to the diverse food captured in female webs.