Anthelmintic Treatment Reveals Sex-Dependent Worm-Gut Microbiota Interactions.

Gastrointestinal helminths interact with the gut microbiota in ways that shape microbiota structure and function, but these effects are highly inconsistent across studies. One factor that may help explain variation in parasite-microbiota interactions is host sex since helminths can induce sex-specific changes in feeding behaviour and diet that might cascade to shape gut microbial communities. We tested this idea using an anthelmintic treatment experiment in wild Grant's gazelles (Nanger granti). We found that in males, anthelmintic treatment induced short-term shifts in microbial diversity and structure within ~40-70 days, but in females, treatment had effects on microbiota structure that emerged over a longer period of ~500 days. Long-term effects of treatment on the microbiota of females were potentially due to sex-specific changes in feeding behaviour since deworming nearly doubled the time females spent feeding, but did not affect feeding time in males. In support of this idea, anthelmintic treatment eliminated associations between microbial diversity and diet in females, and treated females maintained a more stable abundance of microbial taxa and predicted functions. Together, these findings suggest that accounting for host traits can help uncover mechanisms, such as changes in diet, by which helminths interact with the microbiota.