"The Eco-evolutionary Feedback between Cooperative Hunting and Reproductive Skew"Borofsky, TaliaCooperative behaviors may construct niches in which other cooperative behaviors evolve. We investigate how cooperative hunting may influence the evolution of fecundity altruism and reproductive skew. Cooperative hunting, which describes predators hunting prey in a group and sharing the resulting kill, may expand predators’ access to food by allowing them to hunt prey they could not catch alone. However, in some cooperatively hunting groups, such as wolves and African wild dogs, most of the group members are subordinate and perform fecundity altruism, foregoing reproduction so that more resources will go to a dominant reproductive individual or pair. This fecundity altruism results in reproductive skew, defined as an uneven distribution of reproduction. We model a predator population hunting two types of prey-- big prey that is best hunted in groups and small prey that is best hunted alone. Group size changes dynamically, and within each group, subordinates sacrifice a portion of their food to a dominant individual, resulting in reproductive skew. We find that reproductive skew limits the rate at which solitary individuals will join groups, but abundant big prey can favor large groups even if reproductive skew is high. Furthermore, different distributions of reproductive skew favor different distributions of predator group sizes, resulting in downstream changes in the abundance of big prey and small prey. |
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