Assistant Professor Eileen A. Lacey

Department of Integrative Biology

One of the current topics of research in Dr. Lacey's laboratory is physiological markers of senescence in colonial tuco-tucos. This is part of a major research program that explores the evolution of behavioral diversity among vertebrates, with emphasis on studies of mammals. Specifically, by combining field studies of behavior, ecology, and demography with molecular genetic analyses of kinship and population structure, the laboratory members seek to identify the causes and consequences of variation in mammalian social behavior. Dr. Lacey's broad interest is in vertebrate social behavior, and her current research focuses on studies of subterranean rodents from Argentina and Chile. The objectives of this work are as follows:

To identify ecological causes of sociality

Using subterranean rodents as a model system, Dr. Lacey is testing the generality of ecological hypotheses that have been proposed to explain group living among mammals. Currently, a comparative approach is used to identify the factors favoring sociality in two genera of subterranean rodents: Ctenomys and Spalacopus. Because Ctenomys includes both solitary and social species, studies of this genus can be used to explore the reasons for behavioral divergence among closely related taxa. At the same time, comparisons between group-living Ctenomys and Spalacopus provide an important opportunity to identify factors favoring behavioral convergence across larger geographic and taxonomic distances.

To assess the genetic consequences of sociality

Despite compelling theoretical arguments that genetic structure is influenced by social behavior, few empirical studies have explicitly addressed the role of sociality in shaping patterns of genetic diversity. To explore this issue, selectively neutral (microsatellite) and non-neutral (MHC) markers are used to characterize genetic variation in the subterranean rodent species that are the focus of my field studies of the ecology of sociality. In recent studies focusing on length of the lifespan in colonial Tuco-tucos, it has been observed that females (which customarily remain in the burrow) live much longer than males (which roam the countryside). This difference in longevity could be attributed to a greater danger lifestyle of the males than the females. However, when colony of Tuco-tucos were transferred to UCB and maintained under identical conditions, the females still lived longer than the males. By combining analyses of multiple genetic markers with detailed behavioral and demographic data, this work is generating exciting new insights into the effects of social behavior on patterns of genetic diversification in vertebrates.