Meeting Abstract
Understanding how mating cues promote reproductive isolation upon secondary contact is important in describing the speciation process in animals. Divergent chemical cues have been shown to act in reproductive isolation across many animal taxa. However, such cues have been overlooked in avian speciation, particularly in passerines, in favor of more traditional signals such as song and plumage. Here we show evidence for odor as a mate choice cue, potentially contributing to premating reproductive isolation in a chickadee hybrid zone. Using gas chromatography-mass spectrometry, we document significant species differences in uropygial gland oil chemistry between the black-capped (Poecile atricapillus) and Carolina chickadee (P. carolinensis). We also demonstrate significant preferences for conspecific over heterospecific odor cues in wild chickadees using a Y-maze design. Our results suggest that odor may be an overlooked but important mating cue in these chickadees, potentially promoting premating reproductive isolation. In addition, we also show evidence for a loss of odor preferences in adult hybrids. This loss of behavioral response may be coincident with other cognitive deficiencies previously found in hybrid chickadees, and may contribute to the stability of the hybrid zone via postzygotic reproductive isolation.
