Research in my lab occurs at the interface of animal behavior, physiology, ecology and evolution. We seek to understand the mechanisms underlying life history patterns, particularly the timing of major life history events such as reproduction and migration, as well as the selective pressures shaping these patterns.
Appropriate timing of life history transitions such that life history stages (e.g., reproduction, migration) coincide with suitable environmental conditions is critical to the fitness of many organisms. The role of environmental cues in the timing of these life history transitions is currently a central focus of research in my lab. We are interested in both proximate questions (e.g., what are the endocrine mechanisms by which environmental cues influence physiology and behavior?) and ultimate questions (e.g., how do timing mechanisms vary across species, and how has this evolved?). Although photoperiod is the best studied environmental cue used in life history timing, animals may also use other cues including temperature, rainfall, food availability, and social cues. These less studied, non-photic cues are an area of focus in the lab; we are particularly interested in the role of social cues and how multiple environmental cues are integrated to time transitions.
Past work has used both mammalian and avian systems, but we now focus primarily on songbirds, as they are particularly well suited to address our research questions. Our approach is to use both field studies (observational and experimental) and laboratory studies.
Watts, H.E., Cornelius, J.M., Fudickar, A.M., Perez, J. Ramenofsky, M. 2017. Understanding variation in migratory movements: A mechanistic approach. General and Comparative Endocrinology In press.
Squire, M.E., Veglia, M.K., Drucker, K.A., Brazeal, K.R., Hahn, T.P. & Watts, H.E. 2017. Estrogen levels influence medullary bone quantity and density in female house finches and pine siskins. General and Comparative Endocrinology 246:249-257.
Watts, H.E., Robart, A.R., Chopra, J.K., Asinas, C.E., Hahn, T.P., Ramenofsky, M.. 2017. Seasonal expression of migratory behavior in a facultative migrant, the pine siskin. Behavioral Ecology and Sociobiology 71: 9.
Watts, H.E. Edley, B. & Hahn, T.P. 2016. A potential mate influences reproductive development in female, but not male, pine siskins. Hormones and Behavior. 80: 39-46.
Watts, H.E., MacDougall-Shackleton, S.A., & Hahn, T.P. 2015. Variation among individuals in photoperiod responses: Effects of breeding schedule, photoperiod, and age-related photoperiodic experience in birds. Journal of Experimental Zoology Part A: Ecological Genetics and Physiology. 323: 368-374.
MacDougall-Shackleton, S.A., Watts, H.E. & Hahn, T.P. 2015. Biological Timekeeping: Individual Variation, Performance, and Fitness. In: Integrative Organismal Biology (L. B. Martin, C. Ghalambor & H. A. Woods, Eds.). John Wiley & Sons, Inc.
Cornelius, J.M., Watts, H.E., Dingle, H. & Hahn, T.P. 2013. Obligate versus rich patch opportunism: Evolution and endocrine mechanisms. General and Comparative Endocrinology 190: 76-80
Watts, H.E., & Hahn, T.P. 2012. Non-photoperiodic regulation of reproductive physiology in the flexibly breeding pine siskin (Spinus pinus). General and Comparative Endocrinology 178: 259-264.
Holekamp, K.E., Smith, J.E., Strelioff, C.C., Van Horn, R.C. & Watts, H.E. 2012. Society, demography and genetic structure in the spotted hyena. Molecular Ecology 21: 613-632.
Watts, H.E., Blankenship, L.M., Dawes, S.E. & Holekamp, K.E. 2010. Responses of spotted hyenas to lions reflect individual differences in behavior. Ethology 116: 1199-1209.
MacDougall-Shackleton, S.A., Stevenson, T.J., Watts, H.E., Pereyra, M., Hahn, T.P. 2009. The evolution of photoperiodic response systems and seasonal GnRH plasticity in birds. Integrative and Comparative Biology 49: 580-589.
Hahn, T.P., Watts, H.E., Cornelius, J.M. Brazeal, K.R. & MacDougall-Shackleton, S.A. 2009. Evolution of environmental cue response mechanisms: Adaptive variation in photorefractoriness. General and Comparative Endocrinology 163: 193-200.
Watts, H.E., Tanner, J.B., Lundrigan, B.L. & Holekamp, K.E. 2009. Post-weaning maternal effects and the evolution of female dominance in the spotted hyena. Proceedings of the Royal Society B 276:2291-2298.
Watts, H.E. & Holekamp, K.E. 2009. Ecological determinants of survival and reproduction in the spotted hyena. Journal of Mammalogy 90: 461-471.
Van Meter, P.E., French, J.A., Dloniak, S.M., Watts, H.E. & Holekamp, K.E. 2009. Fecal glucocorticoids reflect socio-ecological and anthropogenic stressors in the lives of wild spotted hyenas. Hormones and Behavior 55: 329-337.
Watts, H.E. & Holekamp, K.E. 2008. Interspecific competition influences reproduction in spotted hyenas. Journal of Zoology 276: 402-410
Van Horn, R.C., Watts, H.E. & Holekamp, K.E. 2008. Do female hyaenas choose mates based on tenure? Nature 454 doi:10.1038/nature07122.
Boydston, E.E., Kapheim, K.M., Watts, H.E., Szykman, M. & Holekamp, K.E. 2003. Altered behavior in a large African carnivore associated with increased human activity. Animal Conservation 6: 207-219.