About
I study how animals respond to challenging environments with a focus on how birds behaviorally and physiologically cope with heat. My research takes an organismal perspective with the aim of improving predictions of species persistence and informing conservation decision-making.
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I'm a PhD Candidate in the Rosvall Lab at Indiana University, Bloomington. I will be defending my dissertation in December 2023. I am pursuing a career in professional wildlife biology with the goal of applying my skills in conservation.
Current Research
Organismal effects of heat in a fixed ecological niche: Implications on the role of behavioral buffering in our changing world
Published in Science of the Total Environment
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Increasingly frequent and intense heatwaves generate new challenges for many organisms. Our understanding of the ecological predictors of thermal vulnerability is improving, yet, at least in endotherms, we are still only beginning to understand one critical component of predicting resilience: exactly how do wild animals cope with sub-lethal heat? In wild endotherms, most prior work focuses on one or a few traits, leaving uncertainty about organismal consequences of heatwaves. Here, we experimentally generated a 2.8°C heatwave for free-living nestling tree swallows (Tachycineta bicolor). Over a week-long period coinciding with the peak of post-natal growth, we quantified a suite of traits to test the hypotheses that (a) behavioral or (b) physiological responses may be sufficient for coping with inescapable heat. Heat-exposed nestlings increased panting and decreased huddling, but treatment effects on panting dissipated over time, even though heat-induced temperatures remained elevated. Physiologically, we found no effects of heat on: gene expression of three heat shock proteins in blood, muscle, and three brain regions; secretion of circulating corticosterone at baseline or in response to handling; and telomere length. Moreover, heat had a positive effect on growth and a marginal, but not significant, positive effect on subsequent recruitment. These results suggest that nestlings were generally buffered from deleterious effects of heat, with one exception: heat-exposed nestlings exhibited lower gene expression for superoxide dismutase, a key antioxidant defense. Despite this one apparent cost, our thorough organismal investigation indicates general resilience to a heatwave that may, in part, stem from behavioral buffering and acclimation. Our approach provides a mechanistic framework that we hope will improve understanding of species persistence in the face of climate change.
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Woodruff, M. J., Sermersheim, L. O., Wolf, S. E., & Rosvall, K. A. (2023). Organismal effects of heat in a fixed ecological niche: Implications on the role of behavioral buffering in our changing world. Science of The Total Environment, 164809.
Among-individual variation in heat shock protein responses to intense heat: implications for the evolution of heat tolerance in birds
Under review at Proceedings of the Royal Society B
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Intra-specific variation in heat responses should influence whether and how species adapt to climate change. We experimentally elevated nest temperatures by 4.5°C for 4 hours, focused on 12-day-old tree swallows (Tachycineta bicolor). Nestlings exposed to sub-lethal heat moved towards cooler air at the nest box entrance, they panted more, and they weighed less than controls, suggesting panting-induced water loss. They also exhibited higher heat shock protein (HSP) gene expression in the blood, alongside widespread transcriptional differences related to antioxidant defenses, inflammation, and apoptosis. These heat responses appear to be adaptive: heat-exposed nestlings, particularly those exposed to milder temperatures, were more likely to recruit into the breeding population. Next, we tested five hypotheses on the drivers of variation in HSP gene expression, which was especially marked after heat-exposure. Heat-induced HSP levels were unrelated to individual body mass, or among-nest differences in brood size, temperature, and behavioral thermoregulation. However, nest ID explained a significant amount of HSP variation, which was larger among nests than within nests, pointing to genetic or early developmental factors. Even siblings in the same nest differed by over 14-fold, showing that there is ample individual variation upon which selection may act in the context of climate change.
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Woodruff, M. J., Tsueda, S. N., Guardado, E. A., Rusch, D. B., Buechlein, A., Rosvall, K. A. (Under review at Proceedings of the Royal Society B). Among-individual variation in heat shock protein responses to intense heat: implications for the evolution of heat tolerance in birds.
Heat shock protein gene expression varies among tissues and populations in free-living birds
Published in Ornithology
Climate change is dramatically altering our planet, yet our understanding of mechanisms of thermal tolerance is limited in wild birds. We characterized natural variation in heat shock protein (HSP) gene expression among tissues and populations of free-living tree swallows (Tachycineta bicolor). We focused on HSPs because they prevent cellular damage and promote recovery from heat stress. We used quantitative PCR to measure gene expression of 3 HSPs, including those in the HSP70 and HSP90 families that have robust experimental connections to heat in past literature. First, to evaluate how tissues and, by extension, the functions that they mediate, may vary in their thermal protection, we compared HSP gene expression among neural and peripheral tissues. We hypothesized that tissues with particularly vital functions would be more protected from heat as indicated by higher HSP gene expression. We found that brain tissues had consistently higher HSP gene expression compared to the pectoral muscle. Next, we compared HSP gene expression across 4 distinct populations that span over 20° of latitude (>2,300 km). We hypothesized that the more southern populations would have higher HSP gene expression, suggesting greater tolerance of, or experience with, warmer local conditions. We observed largely higher HSP gene expression in more southern populations than northern populations, although this pattern was more striking at the extremes (southern Indiana vs. Alaska), and it was stronger in some brain areas than others (ventromedial telencephalon vs. hypothalamus). These results shed light on the potential mechanisms that may underlie thermal tolerance differences among populations or among tissues.
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Woodruff, M. J., Zimmer, C., Ardia, D. R., Vitousek, M. N., & Rosvall, K. A. (2022). Heat shock protein gene expression varies among tissues and populations in free-living birds.Ornithology,139(3), ukac018.
Do heat tolerance mechanisms vary across an expanding range?
In progress
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Anthropogenic change is driving rising temperatures across the globe. High temperatures induce changes in animal behavior and physiology that could reflect several types of responses such as plastic adjustments, pre-adaptation, or animals nearing the limits of their coping abilities. Determining the degree to which animals are affected by heat is challenging, and even more challenging is determining how equipped animals are for coping with future heat. To address these challenges and search for a biomarker of heat tolerance, I capitalize on the unique southward range expansion occurring in the tree swallow (Tachycineta bicolor) breeding range. I hypothesize that thermal tolerance facilitates this shift. I assess how nestlings may be differentially equipped to cope with heat across nearly 10 degrees of latitude. To do this I quantify HSP gene expression in 12-day-old tree swallows. Further, I use a sliding window analysis to determine the degree to which recent weather conditions may affect HSP levels (i.e., plastic adjustments) or if differences across populations reflect adaptation over generations (i.e., evolved differences). This study adds to the growing scientific interest in identifying biomarkers of thermal tolerance with which we might predict resilience to future climate conditions.
Four decades of bird banding reveals trends in capture rate and phenotypes across trait groups
Research conducted with the USGS Bird Banding Laboratory and funded by an NSF INTERN grant
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In preparation for submission to Avian Conservation and Ecology
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In the last half century, environments have changed dramatically in ways that may influence species abundance. However, these effects are often not uniform, and there is emerging interest in predicting species persistence in the face of anthropogenic change. Using four decades of fall bird banding data in the eastern USA, we (1) characterized trends in songbird capture rate, (2) assessed the degree to which capture rate trends vary across migratory status, diet guild, and primary breeding habitat, and (3) characterized trends in body size and condition across these trait groups as a window into the mechanisms of capture rate trends. More species increased in capture rate (37%) than decreased (20%), though many species’ trends were not significant (43%). We observed significant capture rate increases in annual residents, short-distance migrants, omnivores, granivores, and species that primarily breed in forest edges, wetlands, or scrub-shrub habitats. Conversely, we observed a significant capture rate decline in long-distance migrants. Across groups, body size largely increased, while body condition largely decreased. These data enhance our understanding of local population dynamics. Our findings serve to generate hypotheses about drivers of species success and identify areas of conservation need in our rapidly changing world.
Mentoring
It is my belief that every good mentor provides their students with the tools to ask their own questions, in pursuit of their own curiosity. This philosophy drives my mentorship style, and I am continuously refining my approaches. I have mentored undergraduate students through summer Animal Behavior REU programs for students from backgrounds historically under-represented in STEM. Through the program students develop an independent research project and learn techniques to achieve their goals. At the end of the summer, students present a poster with their findings. Students have gone on to present their work at international conferences.
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I have also mentored students via IU's Independent Study Course (Biology X490). In this program, students develop and write a research proposal, execute their study, and report their findings. Some of my mentees have taken this course in consecutive semesters, which allows them to build on their project. A mentee expanded her independent study with me into a senior honors thesis. I aim to support mentees in whatever level of involvement they prefer.
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It is my goal to foster a love of science and curiosity in my mentees. Through their research, I strive to provide them with skills that prepare them for their future careers.
Teaching
At IU, I have developed teaching skills as an Associate Instructor (AI). I have been an AI in an upper-level Biology of Birds course multiple times, where I have implemented lab exercises on topics like anatomy and taxonomy and assist in guiding fieldtrips. I was also Head AI for an Introductory Biology lab section, where I was the core instructor for lab and discussion periods. The common denominator in these efforts is the reward of watching a student’s “ah-ha” moment when they grasp a concept – this makes the hours of class prep worth the effort.
Beyond the college classroom, I have developed educational outreach programs for school groups, elementary – high school, that focus on conservation, how scientists study animals, and how animals respond to their environment – even when it’s challenging!
Outreach
Science is for everyone! In each research position, I pursue opportunities to share my science with others and encourage others to be curious. More than what I say, I want people to remember how learning about science makes them feel. I strive to make science accessible, relatable, and exciting... because it is!
Examples: ​
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Skype a Scientist
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USGS Eastern Ecological Science Center Earth Day Open House
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Bird Sculpture Lesson - Claymont Elementary School, DE
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Jim Holland Summer Enrichment Program in Biology (SEP) - Indiana University
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Indiana University Science Fest (in–person multi–department outreach fair)
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Communications Boot Camp for Scientists & Congressional Visits Day
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Anti–racism in STEM Group
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Virtual Indiana University Science Fest (multi–department outreach fair)
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City of Bloomington Parks & Recreation “Nature Days”
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“Day in the Life of a Grad Student” video shared with the Indiana Academy of Science 2020 Kitchen Table Science Project, Indiana University ASURE program, and Indiana University Science Fest 2020.
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Buffalo, NY WGRZ 2 the Outdoors Panel Discussion and Interview
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Jacques Cousteau National Estuarine Research Reserve Educational Outreach Summer Programs
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Canisius Ambassadors for Conservation