Sarah Palmieri, UW Masters Student 

2026 Recipient of Biodiversity Institute Graduate Student Excellence Grant

Department of Zoology and Physiology 

Advisor: Matt Carling

Hybrid zones are powerful models for studying the processes that drive evolution, such as female mate choice, selection, and reproductive isolation. However, the complex underlying dynamics driving these forces are overall poorly understood. This is particularly true in areas where species interactions, range limits, and phenology are rapidly shifting as organisms struggle to keep pace with unprecedented rates of environmental change. A notable example of this trend exists through the Indigo Bunting (Passerina cyanea) and the Lazuli Bunting (Passerina amoena), which hybridize across the Great Plains Suture Zone. Although past work has documented rapid westward shifts of this hybrid zone in recent decades, driven by anthropogenic landscape and climate change, little is known about the patterns of variation in traits important to female mate choice across the contact zone in the context of this shift.
This work aims to identify correlations between phenotypic traits important to reproductive isolation, specifically song and male plumage, and their relationships to genetic ancestry in Passerina males across the contact zone. Given these objectives, we predict a strong relationship between male plumage and genetic ancestry, and no relationship between song and genetic ancestry. By identifying and quantifying these relationships, we can improve our understanding of how these factors contribute to reproductive isolation between the species and how hybridization dynamics will evolve in the face of continued environmental change.