Differing Dietary Nutrients and Diet-associated Bacteria has Limited Impact on Spider Gut Microbiota Composition

Abstract Spiders are a key predator of insects across ecosystems and possess great potential as pest control agents. Unfortunately, it is difficult to artificially cultivate multiple generations of most spider species. Since gut bacterial flora has been shown to significantly alter nutrient availability, it is plausible that the spiders’ microbial community play a key role in their unsuccessful breeding. However, both the gut microbial composition and its influencing factors in many spiders remain a mystery. In this study, the gut microbiota of Campanicola campanulata, specialist prey on ants and are widely distributed across China, was characterized. After, the impact of diet and diet-associated bacteria on gut bacterial composition was evaluated. First, two species of prey ants (Lasius niger and Tetramorium caespitum) were collected from different locations and fed to C. campanulata. For each diet, we then profiled the nutritional content of the ants, as well as the bacterial communities of both the ants and spiders. Results showed that the protein and carbohydrate content varied between the two prey ant species, and that the bacterial communities of the ants were clearly delineated by collection site. However, no significant differences were found in the gut microbiota of spiders that were fed the differing ants. Together, these results indicate that nutritional variation and diet-associated bacterial differences have a limited impact on the microbial composition of spider guts, suggesting that spiders have a mechanism keeping their gut bacterial community stable to ensure normal physiological function and development.