Vasopressin (AVP) and oxytocin (OT) are key modulators of vertebrate social behaviour. Central infusion of AVP or OT promotes pair bonding and the distribution of vasopressin 1a (V1aR) and OT receptors (OTR) differs markedly between monogamous and polygamous species. For example, the monogamous prairie vole (Microtus ochrogaster) has higher densities of V1aR and OTR in prefrontal cortex, basal ganglia and the limbic system than the polygamous montane vole (M. montanus). Although this example is often cited in the literature, this two-species comparison suffers from a confound between sociality and mating system (see above) because the polygamous species is also asocial. Thus, it is unclear whether the differences in V1aR and OTR expression reflect mating system or social bonding. Studying V1aR and OTR expression in the social, polygamous Richardson’s ground squirrel could therefore aid in differentiating whether the neurochemical differences arise from sociality or mating system. This project is being pursued in collaboration with Dr. Alex Ophir (Cornell).
Here are a few photos from our 2015 fieldwork.