Meeting Abstract
Microtine rodents (voles and lemmings) go through marked 3-4 year population cycles throughout the northern hemisphere. The demography of these cycles has been well-documented over decades of research. However, the observation that populations can still go into decline, even when environmental conditions are ideal, has not been explained. Further, there are distinct phenotypes of rodents in the increase and decline phases of the cycle. Thus, there appears to be intrinsic changes in the animals during the peak of the cycle that can limit population growth. We test the hypothesis that high population density, acting through social interactions, induces physiological changes in voles. We experimentally manipulated meadow voles (Microtus pennsylvanicus) in field enclosures at low and high population densities, and examined the impact at multiple levels. Expression differences in key regulatory endocrine receptors in the brain will be discussed.
