Life Science Hour Seminar

Title:

Neuroendocrine and environmental interactions underlying reproductive behaviour in birds

Abstract:

For most bird species reproduction is seasonal and breeding is regulated by environmental cues including photoperiod, food availability, temperature and social interactions. My research interests lie in understanding how these environmental factors coordinate the both the timing and the progression of reproduction and associated behaviour.  I will give an overview of recent research giving examples from both wild free living passerines and domesticated species. The change in day length is one key environmental factor used by birds to determine the time of year to breed.  Birds use extra retinal photoreceptors and their circadian system to interpret the light:dark signal. Gonadal development is under the control of gonadotrophin secretion from the pituitary gland and under increasing day lengths thyrotrophin triggers a flow of molecular events in the mediobasal hypothalamus to increase the synthesis of triiodothyronine which ultimately leads to gonadotrophin releasing hormone synthesis and release until photorefractoriness.  Nonetheless there is inherent flexibility for precisely when birds transition from their reproductive states. Recent investigations into the neural mechanisms underlying complex social and parental care have highlighted the importance of the central mesotocin and vasotocin systems. Neurophysiological studies in zebra finches and Silkie bantam chickens have been particularly useful in elucidating brain mechanisms responsible for behaviours such as nest building, incubation and care of the chicks. There is also evidence that neuroendocrine adaptations underlie the unique behaviour required to maximize survival and reproductive success in capricious environments, e.g. in arctic-breeding passerines like the socially monogamous white-crowned sparrow.  This species rapidly modulates its stress response and adapts behaviour to optimise reproductive success in a very short breeding season which is often fraught with inclement weather events. With such wonderful examples of environmental adaptations and regulation, avian behavioural neuroendocrinologists are entering an exciting period. Using the annotation of many more avian species genomes to devise comparative genomic approaches and species-specific genetic tools, the identification of the genes responsible for integrating environmental information, neuroendocrine signals and reproductive behaviour is within our reach.

About the Speaker:

Professor Simone L. Meddle is a Chair of Behavioural Neuroendocrinology at The Roslin Institute, University of Edinburgh, UK. She leads the British Biotechnology and Biological Sciences Research Council Roslin Institute Program on Improving Animal Production and Welfare. See: https://www.ed.ac.uk/roslin/about/contact-us/staff/simone-meddle. Simone received her undergraduate and PhD degrees from the University of Bristol UK. She has authored more than 80 peer-reviewed manuscripts and book chapters. Much of her work has involved identifying how environmental cues can trigger the expression of functionally important behaviour in birds and rodents in relation to the neuroendocrine system. These include adaptations of the stress response, regulation of food intake, reproductive behaviour including sexual, aggressive and maternal behaviour and photoperiodic time measurement. She has spent the last 20 years studying hormone, brain-behaviour interactions in wild song birds in the field, including in those breeding in the Arctic. When she is not at work she can be found walking her dog on the beach along the beautiful Scottish coastline.

Alaska Unit Research Review

Details:

Talks (Elvey Auditorium) and posters (Globe Room) from AKCFWRU graduate students, post-docs, and faculty about fisheries, wildlife, and ecological research. Agenda is posted at https://www.akcfwru.uaf.edu.

Life Science Hour Seminar

Title:

Avian olfaction: The road less travelled

Abstract:

Life Science Hour Seminar

Title:

Pattern and anomaly in species-climate relationships: investigating distributions, abundance, microrefugia, and mechanisms

Abstract:

The paleorecord suggests that numerous species have persisted through several mass-extinction events associated with glacial-interglacial cycles. Sharp increases in predicted rate of temperature change through 2100 have been suggested to be 10,000-100,000 times faster than the rate of niche evolution observed in the paleorecord; however, both paleo- and contemporary species responses to climatic variability have been very diverse. Wildlife and land managers desire rules of thumb or patterns that might indicate which species and populations are more vulnerable to contemporary global change, and which are more likely to be able to accommodate and cope with such change. Results of recent and ongoing research on mountain-dwelling animals illustrate numerous take-home messages of how species are responding to contemporary global change – both in terms of local distributional losses and of surprising exceptions to the 'rules'.

Drawing from Beever's research experiences over the last quarter-century, the presentation will use examples from across western North America to illustrate weather-based stress and refugial dynamics at multiple scales. Fundamental to all this work – because it is the key to informing climate-adaptation management and conservation actions – is research into how and why species and communities are responding. Without such understanding of mechanisms, management and conservation of natural resources in an era of global change may be relegated to trial and error. The presentation will also share ideas that challenge the assumption of spatial and temporal niche conservatism. The presentation will end with a global, all-taxa investigation of the factors and dynamics that affect species’ adaptive capacity. This will include a brief synopsis of the taxonomic, climatic, geographic, and life-history contexts in which species have exhibited behavioral ability to accommodate acute and chronic weather stresses

About the Speaker:

Erik Beever has over 85 publications in diverse scientific journals and in numerous subdisciplines of biol­ogy. He has performed field research on plants, soils, amphibians, birds, reptiles, fishes, and insects, as well as small, medium, and large mammals. His work has spanned salt-scrub, sagebrush-steppe, alpine, subalpine, subarctic, riparian, primary and secondary temperate and tropical forest, and coastal ecosystems of the western hemisphere. In addition to seeking to understand mechanisms of biotic responses to long-term weather patterns and variability, he has also focused on disturbance ecology and monitoring in con­servation reserves, all at community to landscape scales, as well as other topics of conservation ecology, wildlife biology, and landscape ecology. He is interested in questions at the nexus of basic and applied science, especially those that also inform management and conservation efforts for species, communities, and ecosystems. After receiving his undergraduate degree in Biological Sciences at U.C. Davis, Erik received his Ph.D. from the Progam in Ecology, Evolution, and Conservation Biology at the University of Nevada, Reno.

Thesis Defense

Title:

Feeding ecology of scaup ducklings across a heterogeneous boreal wetland landscape

Abstract:

Understanding how patterns of food resources influence the behavior and fitness of free living animals is critical in predicting how changes to such resources might impact populations. The boreal region of North America is relatively undeveloped and contains abundant freshwater lakes and wetlands. These largely pristine and stable habitats harbor high densities of aquatic invertebrates, which are a critical food source for the numerous waterbird species that breed in the boreal. Invertebrates are of particular importance for the optimal growth and survival of waterbird chicks. However, observations of long-term change to boreal aquatic habitats and their invertebrate populations associated with a warming climate has been implicated in the declines of some boreal breeding waterbirds, such as the lesser scaup (Aythya affinis). Lesser scaup are known to feed extensively on amphipods, a freshwater crustacean; however, ducklings have been shown to have a diverse diet. Our goal was to use the naturally occurring heterogeneity of aquatic invertebrates across boreal lakes within the Yukon Flats National Wildlife Refuge in interior Alaska to better understand how changes in invertebrate prey resources might affect diet selection and growth in lesser scaup ducklings. First, we used a stable isotope approach to quantify the variation in the trophic niche within our population of ducklings. We found that as a population, lesser scaup ducklings consume a variety of aquatic insects, crustaceans and mollusks, and that variation in the population diet is largely attributable to variation in diet between birds from different lakes with different invertebrate communities. Second, we used the same habitat heterogeneity to examine how gradients of invertebrate abundance relate to the growth of ducklings. We observed that lesser scaup ducklings experienced reduced growth rates in lakes that had little to no amphipods. Taken together, these results suggest that while lesser scaup ducklings are a flexible consumer that can adapt to changes in invertebrate populations, ducklings may face negative fitness repercussions when consuming prey other than amphipods.

Life Science Hour Seminar

Title:

How does light modulate mood and cognition?

Abstract:

Light has profound effects on behavior and physiology in mammalian species. The level of illumination during the day has been found to be positively associated with emotional well-being and optimal cognitive functions in humans, although the underlying mechanisms are poorly understood. Our recent work has developed a diurnal rodent model, the Nile grass rat (Arvichantis niloticus), to explore the neural pathways mediating the effects of light on emotion and cognition. Animals were housed under either summer- or winter-like lighting conditions by manipulating day-length or daytime light intensity. The results revealed increased depression- and anxiety-like behaviors as well as impaired hippocampal functions in grass rats housed in winter-like conditions without sufficient daytime light exposure. Utilizing this unique diurnal model, we have identified a few neural substrates that likely mediate the effects of ambient light on emotion and cognition. A better understanding of how light modulates emotion and cognition will contribute to novel preventive and therapeutic strategies for mood disorders as well as cognitive decline associated with aging and dementia.

About the Speaker:

Lily Yan is an Associate Professor in the Department of Psychology and Neuroscience Program at Michigan State University. She earned her Ph.D. in Physiology from Kobe University School of Medicine (Japan) and received post-doctoral training at Columbia University, during which her research focused on the molecular and neural mechanisms of circadian rhythms. She joined the faculty at Michigan State University in 2008 and started to investigate the modulatory effects of ambient light on emotion and cognition. Using a diurnal rodent model, her research program is aimed to understand the neural mechanisms through which light affects mood, anxiety and spatial learning, and ultimately to provide insights into how environmental lighting conditions modulate emotion and cognition in humans.