Hormonal regulation of singing behavior
I’ve been studying the intricate interaction between hormonal mechanisms and vocal communication systems in songbirds, particularly the role of testosterone (T) in modulating singing behavior and neuroplasticity. Songbirds provide a valuable model for exploring how hormones like testosterone influence brain structures, such as the HVC and song control nuclei, that are critical for song learning and production. My colleagues and I have investigated sex differences in this regulation in canaries (serinus canaria), revealing that while T enhances neuroplasticity and song performance in both sexes, significant differences persist in vocal capabilities, with males typically exhibiting more robust singing behavior and larger song control nuclei. I also study physiological constraints on vocal production, demonstrating how anatomical factors like syrinx muscle structure impact the complexity and attractiveness of songs, which in turn can influence mate selection and reproductive success.
Additionally, I’m interested in understanding adult neuroplasticity, exploring how testosterone induces changes in neuronal proliferation and migration, particularly in relation to seasonal hormonal fluctuations. These studies not only provide insights into animal communication but also offer broader implications for understanding the biology of neuroplasticity in adult brains.
Evolution of song complexity and performance
My research on house wrens (Troglodytes aedon) during my Ph.D. explored the role of geographic and behavioral variability in the evolution of birdsong repertoires. House wrens inhabit all the Americas and exhibit substantial variability in their migratory patterns and breeding systems, making them an ideal species for studying song diversification. My work linked male song diversity and breeding success, showing that males with more complex and diverse songs had higher reproductive success. In addition, my colleagues and I revealed a significant latitudinal variation in song performance and complexity. We found that males from northern populations produced longer and more complex songs with higher trill rates compared to their southern counterparts. These differences in song characteristics were linked to the breeding systems present across different latitudes.
Anthropogenic effects on birdsong
Elevated average temperatures and the increasing frequency of extreme temperature events due to climate change have far-reaching impacts on animal populations. However, there is a noticeable gap in research regarding the impact of ambient temperature on animal behavior, particularly on acoustic communication and the underlying neuroendocrine and physiological mechanisms supporting it. I recently started investigating the potential influence of ambient temperature on song performance and structure in zebra finches (Taeniopygia guttata). Understanding the impact of temperature on the production of acoustic signals is particularly significant as it directly relates to the reproductive success of many animal groups, including songbirds. Sexual reproduction is generally preceded by elaborate courtship behaviors, where males and females identify potential mates of the same species through the exhibition of mating displays. Any compromise in the clarity, accuracy, or attractiveness of these signals can influence how females assess and respond to male displays, potentially hindering the successful initiation of sexual reproduction, and reproductive success. This issue has broader implications for mating and reproduction across different animal groups susceptible to changes in ambient temperature.