Levesque’s NSF CAREER Award supports study of small mammal thermoregulation, energy use in changing climate


Danielle Levesque

Endothermy, or the ability to maintain body temperature at a constant and elevated level, is a signature mammalian characteristic. But global climate change is affecting mammalian temperature regulation in a variety of ways as it reshapes natural habitats. Understanding the impact of temperature fluctuations on mammals that inhabit diverse environments is critical to identifying vulnerable species and predicting population redistribution in the face of global change.

Danielle Levesque, a University of Maine assistant professor of mammalogy and mammalian health, will use a National Science Foundation (NSF) CAREER Award of nearly $920,000 to study temperature regulation in diurnal and nocturnal equatorial small mammals in an effort to describe the impacts of climate change on species living in aseasonal tropical environments.

Levesque, whose research has focused on understanding the variability and nuances of mammalian temperature regulation and energetics, has conducted collaborative research with scientists from the Institute of Biodiversity and Environmental Conservation at the Universiti Malaysia Sarawak on the island of Borneo, a hot spot for mammalian diversity, since 2014. She seeks to enhance understanding of the relationships between past and current environmental temperatures and the life history and energetics of the island’s small mammals.

“My research lies at the intersection of comparative physiology, ecology and evolutionary biology,” Levesque says. “As an evolutionary and ecological physiologist, I am primarily interested in comparative energetics and evolution of mammalian temperature regulation.”

The proposed project will fill a void in the scientific knowledge of mammalian thermoregulation, as much of the previous work has been conducted with northern hemisphere species who live in latitudes with cold temperatures and a great degree of seasonality. Those species experience significant daily and annual changes in environmental temperatures, in contrast to the relatively consistent equatorial conditions on Borneo.

“As we seek to understand current global patterns, and to predict vulnerabilities in response to changing global climates, we are in need of high quality physiological data characterizing species-specific responses to climate,” Levesque says.

She describes characterization of the functional energetics of free-living tropical mammals as critical to understanding current species distributions and facilitating accurate prediction of mammalian responses to changing climates. Because endothermy is not represented by a single phenotype but rather manifests as an energetic continuum, predicting species vulnerability and response to climate change can be challenging.

Target species for this study include six endemic small mammals that represent a range of thermal profiles and body size: Low’s squirrel, Sundasciurus lowii; Prevost’s squirrel, Callosciurus prevostii; Müllers Rat, Sundamys muelleri; the dark-tailed tree rat, Niviventer cremoriventor; the moonrat, Echinosorex gymnura; and the large tree shrew, Tupaia tana.

Since joining the UMaine faculty in 2015, Levesque has focused on development of new standardized methodologies that will facilitate delineation of thermoregulatory parameters across the spectrum of endothermic mammals.

Her 5-year research plan includes field and laboratory-based experiments intended to allow for direct comparison of physiological data across climate zones and species. Advancements in microchip technology, radio tracking and biologging will support collection of data from free-living mammals. When considered with existing data, the thermal profiles and basal metabolic measurements gathered in Borneo will support macroanalyses that describe the impact of increasing environmental temperatures on activity, phylogeny and body size in endothermic mammals in aseasonal, tropical environments.

Levesque plans to share her findings in UMaine’s classrooms and beyond. A few graduate and undergraduate students will join her and her Malaysian collaborators in the field as part of an integrated educational model based in near-peer mentoring, field-based learning and analysis of real-world data. Data collected by the project will also be used in Levesque’s graduate and undergraduate classes at UMaine.

“Through first-hand experience with novel datasets from a unique environment, students will learn the importance of thermoregulatory physiology in understanding how animals respond to their environment,” Levesque says.

K–12 students in Maine will also learn about the impact of climate change on mammalian evolution through the participation of Levesque and her graduate students in the “4-H Follow a Researcher” program and through an interactive toolkit for middle school students to be developed in collaboration with UMaine’s Cooperative Extension 4-H STEM Ambassadors Program. These initiatives will connect UMaine researchers to elementary classrooms while on expedition to inspire discussion of climate change in Borneo, in Maine and around the world, and to prompt students to explore scientific careers that will prepare them to address critical global problems.

“We have the unique opportunity to use novel data collected from an area of global and scientific historical significance to convey concepts of organismal physiology, energetics and evolution to train the next generation of STEM-literate graduate and undergraduate students,” says Levesque.