Sex-specific interactions of microbial symbioses on cricket dietary selection

Authors: Schmid, Ryan; Lehman, R - Michael; Lundgren, Jonathan

Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/10/2014
Publication Date: 8/4/2014
Citation: Schmid, R.B., Lehman, R.M., Lundgren, J.G. 2014. Sex-specific interactions of microbial symbioses on cricket dietary selection. Environmental Entomology. 43(4):896-902.

Interpretive Summary: Gut microorganisms perform many roles in improving the nutrition of animals, although we are only beginning to understand the complex ecology that drives these relationships. Crickets are abundant insects that eat many different foods (of varying qualities), and microbes are known to help these crickets to digest relatively low quality foods. But different sexes of crickets (like many animals) have different nutritional needs, and so microbes could be important for digestion in one sex but not another. We tested the hypothesis that gut bacteria differentially affects male and female cricket dietary choices. We compared seed and prey consumption in crickets with their gut microbiota manipulated through the use of antibiotics. The results demonstrate that removing the gut bacteria of crickets had very different effects on dietary choices of males versus females, and sex needs to be factored in when examining the effects of bacterial symbionts on animal fitness and behavior.

Technical Abstract: The nutrients found in prey and non-prey foods, and relative digestibility of these foods, has a major influence on diet selection by omnivorous insects. Many insects have developed symbiotic relationships with gut bacteria to help with extracting nutrition from non-prey diets. Gryllus pennsylvanicus (Burmeister) (Orthoptera: Gryllidae) was assigned to one of two treatment groups, antibiotic treated and non-antibiotic treated, and consumption of seeds (non-prey) and eggs (prey) were measured. Male crickets administered antibiotics consumed more seeds and greater seed weight, while antibiotic-fed female crickets consumed fewer seeds and less seed weight, relative to the untreated male and female crickets respectively. Both male and female antibiotic-treated crickets consumed similar weight of eggs as non-antibiotic treated male and female crickets respectively. These results provide evidence that gut symbionts influence diet selection of male and female G. pennsylvanicus differently. This sex-specific dietary selection may be due to the fact that male and female crickets have different nutritional requirements.