The Scent Gland Microbiomes of Wild Tamarins Provide New Insight Into Microbial Contributions to Olfactory Communication

The microbiome of mammalian scent glands is thought to contribute to the production of odorant compounds involved in sensory communication. Yet, the extent to which glandular microbiomes contain bacteria relevant to odor production and vary by host species, scent marking behavior, or gland morphology remains poorly understood, particularly in wild animals. We sampled microbes collected from skin swabs of suprapubic and sternal scent glands in wild Peruvian saddleback tamarins (<i>Leontocebus weddelli</i>; <i>n</i> = 19) and emperor tamarins (<i>Tamarinus imperator</i>; <i>n</i> = 20) to better understand glandular microbial communities. We aimed to: (1) profile glandular microbiomes of both species, focusing on odor-related taxa and metabolic pathways, and (2) determine whether suprapubic glands, more often in contact with the external environment, had higher diversity and distinct composition of odor-related taxa and pathways compared to sternal glands. We generated metagenomic reads using short-read DNA shotgun sequencing from glandular swabs. We identified 18 odor-associated microbial taxa in both tamarin species, mainly <i>Staphylococcus</i> and <i>Corynebacterium</i>, and 26 pathways, including pyruvate fermentation and amino acid metabolism. Suprapubic glands had lower Shannon alpha diversity relative to sternal glands, especially in <i>L. weddelli</i>. The glands of <i>L. weddelli</i> also differed in taxonomic composition, with odor-related taxa more abundant in suprapubic glands. Our results provide evidence for the involvement of scent gland microbiomes in host communication biology. Glandular specializations differed not only between closely related tamarin species but also between gland types within the same individuals, suggesting a nuanced pattern of host-microbe coevolution that may shape interactions important for olfactory communication.