Abstract. I will discuss food-sharing vampire bats as a model system for understanding the development and regulation of long-term cooperative relationships. I first review observational and experimental evidence that vampire bat food sharing is enforced by both nepotism and reciprocity in the broad sense. Second, I ask: why should individuals invest in cooperative relationships with nonkin when kin are available? One explanation is that a kin-limited support network is too small and risky. Investing in a higher quantity of social ties at the expense of relationship quality (“social bet-hedging”) can reduce the risks posed by unpredictable social environments. As predicted by the social bet-hedging hypothesis, I show how experimental removal of key food donors revealed the hidden importance of weak nonkin bonds. Third, I ask: how does a new cooperative relationship develop between complete strangers? One important but untested theory is that individuals develop new cooperative relationships by ‘raising the stakes’: gradually increasing low-cost investments to decide on whether to make higher-cost investments. This behavior has been demonstrated in human strangers playing cooperative games but not in a more ecologically realistic setting. By tracking the development of cooperative relationships between previously unfamiliar wild-caught vampire bats, I show that unfamiliar females selectively escalate low-cost investments in allogrooming to develop higher-cost reciprocal food-sharing relationships. I also discuss current work on social foraging by tracking vampire bat social networks in the wild at fine temporal resolution.
Collins Conference Room
Gerald Carter (The Ohio State University)
This event is private.