Dr. Jessica Graham

Dr. Graham is an Assistant Professor of Biology at Black Hills State University. She is interested in understanding how organisms use cues in their environment to appropriately time reproduction, and how those decisions influence behavior, physiology, and fitness. Using temperate-breeding songbirds (primarily the dark-eyed junco), Dr. Graham approaches this question from many different directions.

Olfaction: Until recently, birds were considered anosmic (or unable to smell). One area of her research is studying how seasonal changes in olfaction may confer fitness advantages or costs. For example, birds that build nests with specific, odorous herbs can reduce the presence of bacteria and increase offspring size. However, not only is activation of the olfactory system energetically expensive, even at its resting state, the system has a high energy demand compared to neural activity in other parts of the brain. If natural selection acts upon the olfactory system, organisms could shift seasonal timing to adapt to a changing environment.

Chronobiology: She also studies the interactions between biological rhythms and reproductive timing. Biological rhythms are conserved across taxa, driving physiology and behaviors to create individual phenotypes. An example of this behavior in humans is the 'morning lark' and the 'night owl'. These phenotypes are responsive to changes in environmental cues, such as photoperiod, and these cues lead to activation of the reproductive system. In seasonal breeders, we see highest reproductive success occurring early in the season, when few individuals are breeding. Dr. Graham studies how rhythmic phenotypes are related to seasonal timing decisions and behaviors, allowing few individuals to breed early and obtain highest reproductive success.

Telomere Biology: Dr. Graham is also interested in the physiological costs that may come with breeding early, in particular those associated with aging. Telomeres, the protective caps on the end of our DNA, are good proxies of biological wear and tear as they shorten with age and in response to stress. Telomere length and loss rates have also been shown to be predictive of

longevity in many taxa. Breeding at a time when temperatures are cooler and less food is available could be the cause of increased telomere loss as these individuals must allocate energy to both reproductive functions and increased thermoregulatory demands.

Physiological Ecology: She also has an interest in understanding how the environment impacts hormones, which in turn regulate behavior. Changes in hormones can result in changes in sensitivity of the olfactory system, adjustments in timing of biological systems, and increase telomere loss. Learning more about how the environment influences physiological systems and behavior can help us further understand the ability of organisms to adapt to increasing levels of urbanization and rapidly changing climates. 

She is always interested in exploring new areas of study that can help address these overarching questions and encourages interested individuals to reach out if they would like to know more.