Date of Graduation

Summer 2026

Degree

Master of Science in Biology

Department

Biology

Committee Chair

Sean Maher

Abstract

The little brown bat (Myotis lucifugus) has experienced drastic population declines across North America due to the recent disease white-nose syndrome (WNS). Previous studies have identified putatively adaptive alleles (PAAs) that may give individuals a greater likelihood of survival. However, there could be geographic-specific adaptation, creating different adaptive landscapes. Additionally, there may be energetic trade-offs between disease survival and reproductive output, and it is not clear what the long-term survival outcomes for the species may be as a result. Long-term evolutionary outcomes are unclear because this species has a lifespan exceeding the arrival of WNS and is difficult to age, making it difficult to assess recruitment and long-term outcomes. To evaluate whether the remnant population may be facing variable adaptation or an adaptive extinction debt, genetic samples were collected from five populations to screen individuals for frequencies of PAAs, and assess whether these PAAs may be associated with reduced reproductive output. Across temporal scales, I found that young-of-the-year (YOY) had similar PAA proportions compared to historical samples, but lower proportions than first-wave survivors. I also found that PAAs associated with potential reproductive issues were found less often among YOY compared to other PAAs. Collectively, these results suggest that survivors with alleles conferring viability are reproducing, but that some of their potential adaptation may have come at the cost of reduced reproductive output. I hope that this study can inform population management and conservation decisions for little brown bats across their range by identifying where, and to what extent, populations are genetically adapting to WNS.

Keywords

adaptation, selection from standing genetic variation, reproductive trade-offs, antagonistic pleiotropy, population genetics, conservation genetics

Subject Categories

Evolution | Population Biology

Copyright

© Carly R. Trujillo

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