Behaviour 2019
Variation in songbird microbiota across populations but not sexes
Leanne A. Grieves1, Greg B. Gloor2, Tosha, R. Kelly3, Mark A. Bernards2, Elizabeth A. MacDougall-Shackleton2. 1McMaster University, Hamilton, ON, Canada; 2Western University, London , ON, Canada; 3Louisiana State University, Baton Rouge, LA, United States

Symbiotic microbes can affect host odour, providing cues of identity or sex. In birds, preen oil is a proxy for body odour. We hypothesized that population and sex differences in the preen oil chemistry of song sparrows reflect underlying differences in preen gland microbiota, predicting that these microbes also differ across populations and sexes. We further predicted that pairwise similarity in the composition of preen gland microbiota would covary with preen oil chemical composition. Consistent with prior work, we found population and sex differences in preen oil chemistry. We found population but not sex differences in the composition of preen gland microbes. Overall similarity in preen gland microbiota did not significantly covary with preen oil chemistry, but we identified a subset of microbes that maximally correlated with preen oil composition. While both preen gland microbiota and preen oil composition differ across populations, there was no overall association that would implicate microbes in mediating variation in olfactory cues associated with preen oil. Certain subsets of microbes could mediate olfactory cues in birds, but experiments are required to test this.