Brugia Malayi - Clark Science Center - Smith College

Neuroendocrinology of Sociality in Meadow Voles
Kara Reitz
There is a lot of interest in the neurobiology of social behavior. However, little is understood about mechanisms supporting
relationships between individuals who are not mates. In the summer months female meadow voles (Microtus pennsylvanicus) are
reproductively receptive and are also extremely territorial and solitary. In the winter months voles are markedly more social and will
exhibit more huddling behavior among their peers. The aim of this study was to examine the role of seasonal variation in anxiety in
non-reproductive affiliative behaviors in meadow voles by reducing anxiety with diazepam and by manipulating day-length cycles.
Voles were reared in two different day lengths to simulate the light shifts in summer and winter months: long day (14 hours of
light, 10 hours of dark) and short day (10 hours of light, 14 of dark). They were also assigned to three distinct drug treatment groups
that included a high dose of diazepam, a low dose of diazepam, or saline. To examine anxious behavior three anxiety tests were
given over a two-week period: the elevated plus-maze, light/dark box and open field tests. Following this sequence of anxiety tests a
partner preference test was given to examine the social behavior of the voles. The partner preference test consists of three chambers:
two tethered voles on each end of the apparatus and a free vole. The free vole was allowed to roam between the chambers over a
three-hour period and the time spent huddling versus alone was then analyzed. In order to examine the effect of diazepam, it was
administered before partner preference tests and the EPM.
Based on what is known about both the anxiety and social behavior of meadow voles, it is expected that short day voles will
exhibit more social behavior in the partner preference tests and lower anxiety in other behavioral tests. Conversely, long day voles
are expected to exhibit less social behavior in the partner preference tests and more anxiety in the other behavioral tests. Diazepam
is expected to reduce anxiety behaviors in the EPM and may alter social behaviors in partner preference tests across one or both day
lengths.
Thus far there has not been much research done on the formation of non-reproductive social relationships in mammals, and
this study aims to characterize natural variation in anxiety as a mediator of social behavior. (Supported by the Frances Baker Holmes
Fund)
Advisor: Annaliese Beery
References:
Hendrie, C.A., Eliam, D., Weiss, S.M. 1997. Effects of diazepam and buspirone on the behaviour of wild voles (Microtus socialis) in two models of anxiety. Pharmacol
Biochem Behav 58, 573-576.
Ossenkopp, K.P., van Anders, S.M., Engeland, C.G., Kavaliers, M. 2005. Influence of photoperiod and sex on locomotor behavior of meadow voles (Microtus
pennsylvanicus) in an automated light-dark ‘anxiety’ test. Psychoneuroendocrinology 30, 869-879.
2012
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