Early developmental exposure to inorganic mercury does not alter affiliative behavior of adult prairie voles (Microtus ochrogaster).

Mercury chloride exposure through drinking water in adult male prairie voles (Microtus ochrogaster) has been shown to alter their social behavior. Here, we examined the potential disruption of adult social behavior in prairie voles that were exposed to 60 ppm mercury during early development. We used a cross-fostering approach to test the effects of mercury exposure: (1) from conception until birth; (ii) from birth until weaning; and (iii) from conception until weaning, on adult affiliative behavior. Untreated and mercury-treated voles were given the option of remaining in an empty cage or affiliating with a same-sex conspecific in a 3-h choice test. We found that early developmental mercury exposure had little if any effect on the reproductive success of breeder pairs or on affiliative behavior by either sex when subjects were tested as adults. These results suggest that, at least in the context of the behavior tested, the effects of early developmental exposure to mercury do not permanently alter adult prairie vole affiliative behavior, or do so in a way that is too subtle to be detected using the current testing paradigm.