Khangar, P. | bioRxiv Science

bioRxiv2026

TRACKING THE COMPOSITION AND STABILITY OF MICROBIOME ACROSS INDIAN SOCIAL HONEYBEES FORAGING IN A HOMOGENOUS RESOURCE LANDSCAPE

Microbial communities are essential for host health and ecosystem stability. However, whether host identity or shared foraging resources shapes microbiome structure among co-occurring species remains poorly understood. We studied bacterial and fungal communities of four Indian honeybee species in a mustard monoculture resource condition, integrating behavioural observation-based pollinator data with microbial co-occurrence networks derived from metabarcoding. Microbiome composition was linked to host identity rather than foraging behaviour, bee abundance, or landscape use. While core bacterial taxa were shared, relationships among bacterial cobionts, unlike those among fungal genera, remained species-specific. Microbial diversity, along with community structure and function, influenced network stability, with a highly modular microbial network of Apis cerana exhibiting more resilience to simulated perturbations. In summary, host-specific filtering shaped the microbiome more than resource homogenisation, with closely related species facing unique risks of microbial collapse, with broader implications for vulnerability to microbiome imbalance, environmental stress, and emerging infections.

ecology↗

bioRxiv2024

Microbiota drives the sexually dimorphic infection outcomes in mealworm beetles

Sexually dimorphic responses to pathogenic infections in animals may stem from sex-specific differences in their life history and immune investment. Recent evidence highlights that such sex-specific variations in immune responses can also be critically regulated by microbiota. However, direct experiments to test how microbiota jointly impacts sex-specific immunity and vulnerability to pathogens are still limited. To this end, we used Tenebrio molitor beetles to first establish that sexes appear to differ in their microbiota composition and infection responses. Females were more vulnerable to bacterial infections and carried a higher bacterial load than males. When we depleted the microbiome, only females improved their post-infection survival, leading to a loss of sex-specific infection outcomes. Males, on the other hand, remained unaffected. Microbiota reconstitution (via feeding on faecal matter) of microbiota-depleted females increased their susceptibility to infection again, restoring the sexual dimorphism. We thus found a causal association between microbiome and infection responses. We also found reduced expression of an antimicrobial peptide tenecin 1 in females, which could be associated with their higher infection susceptibility, but such immune gene-vs-phenotypic associations were not consistent across microbiota manipulations. Immune strategies that are required to mediate the causal links between microbiome and infection response might thus vary with microbiota manipulations, warranting future investigations.

evolutionary biology↗