The Effects of Cage Size Variation on Prairie Vole Monogamy

• Rose Pristas, Neuroscience, University of Delaware

• William Kenkel, Psychological and Brain Sciences, University of Delaware

     The partner preference test (PPT) is a common method used to assess pair bonding in monogamous rodents. Prairie voles (microtus orchogaster) are often used for these tests due to their monogamous nature. Prairie voles at the University of Delaware have displayed stronger partner preference relative to voles at previous institutions. A possible explanation for this is that the voles at the University of Delaware are housed in larger cages than at other institutions. In order to assess the effects of cage size on pair bondings, adolescent male voles were housed in either small (35cm x 23cm) or conventional (44cm x 22cm) sized cages until sexual maturity. Male voles were paired with their familiar partner either 12 hours or 16 hours prior to being introduced to a 3-chamber arena constructed from expanded PVC (~50cm x 100cm). This arena allows a choice of spending time with the familiar “Partner” of the opposite sex, a completely unfamiliar “Stranger” animal, or an empty, neutral chamber. The experimental male will be free to move throughout the arena while the two stimulus females are loosely tethered within their separate chambers, by means of a collar attached to a wire leash (~15cm). Video recordings were used to score partner preference behavior during 3 hour trials. Results demonstrated that voles spent more time with their mate regardless of cage size, suggesting that cage size does not affect partner preference. This could be used as a translational model for wild prairie vole behavior, where cage size reflects territory size. Research needs to be continued to determine if further decreasing (or increasing) cage size will impact the monogamous behavior of the prairie vole. In addition, detailed scoring is needed to determine whether males simply spend more time in their partner’s chamber, or if they exhibit bonding behaviors such as huddling with their partner.