# Gut Microbiome Differences Across Mixed-Sex and Female-Only Social Rearing Regimes in Female Field Crickets Teleogryllus occipitalis (Orthoptera: Gryllidae)

## TL;DR

Female field crickets raised in mixed-sex groups have different gut microbes and functions compared to those raised in all-female groups.

## Contribution

This study uses whole-genome shotgun metagenomics to reveal social rearing effects on gut microbiome composition and function in crickets.

## Key findings

- Mixed-sex reared females had more genes for nutrient breakdown and microbial competition.
- Female-only reared crickets showed higher stress resistance and nitrogen fixation gene abundance.
- Social rearing regimes significantly influence gut microbiome diversity and function.

## Abstract

Crickets are useful model organisms with incomplete metamorphosis for understanding insect physiology and behavior. Like all animals, they host a gut microbiome, a community of tiny organisms that helps digest food, fight disease, and support reproduction. Social environment, such as being reared under mixed-sex versus female-only group-rearing regimes, may change the female gut microbiome, but this has rarely been tested in insects using genetic approaches. We studied the field cricket Teleogryllus occipitalis and compared the gut microbiome of females in mixed-sex rearing with that of females in female-only rearing. Using whole-genome shotgun metagenomics, we found consistent differences in both microbial composition and gene content between the two rearing regimes. Females from mixed-sex rearing showed higher relative abundances of microbial genes annotated to breaking down complex nutrients and competing with other microbes, whereas females from female-only rearing showed more genes annotated to stress tolerance and coping with limited nutrition. These findings suggest that the social rearing regime (mixed-sex vs. female-only) is associated with the gut microbiome of female crickets.

The insect gut microbiome contributes to various host physiological processes and behaviors, such as digestion, nutrient absorption, immunity, mate choice, and fecundity. The social environment can shape gut microbial communities. Mixed-sex vs. female-only rearing is an important social context because it differs in exposure to the opposite sex and mating opportunities, which may in turn affect female physiology that may influence their gut microbiome. Despite the growing recognition of these social-microbial interactions, most studies have relied on 16S rRNA amplicon sequencing or qPCR, which provide only coarse taxonomic resolution and limited functional insight. In this study, we used whole-genome shotgun metagenomics to examine changes in microbial diversity and functional gene composition in the female field cricket Teleogryllus occipitalis (Serville) (Orthoptera: Gryllidae) reared under two social conditions: mixed-sex rearing and female-only rearing. Species richness and diversity analyses revealed that community composition separated between females from mixed-sex and female-only rearing. Functional profiling indicated higher relative abundances of genes annotated to nutrient processing and inter-bacterial competition in females from mixed-sex rearing, whereas females from female-only rearing showed relative enrichment of genes annotated to stress resistance and nitrogen fixation. These findings provide a genome-resolved foundation for testing how social rearing conditions covary with gut microbiome composition and functional potential in female crickets.