Meeting Abstract
The extirpation of their natural predators has necessitated the management of feral horse populations across the US. The contraception of females (mares) with porcine zona pellucida (PZP) is a popular option; however, effects to behavior can be substantial. For example, on Shackleford Banks, an island off the coast of North Carolina, treated mares have demonstrated decreased social fidelity, moving among historically stable groups (bands) more frequently than untreated mares. This behavior is consistent across the island, where differences in ecology dictate the degree of territoriality demonstrated by band stallions. We compared the gut microbial communities of mares that changed bands vs. those that did not while controlling for island region (a reliable proxy for stallion territoriality). We found that group changing behavior correlated with differences in gut microbial communities of mares living in territorial, but not non-territorial regions. The mechanism(s) behind these differences remain unclear, but we will present data on several candidates, including dietary differences, physiological effects of sub-fertility, and links between male aggression and female cortisol levels.
