By-product group benefits of non-kin resource-sharing in vampire bats

Abstract

We develop an agent based model (ABM) to simulate the behaviour of a colony of vampire bats (Order: Chiroptera) and study the by-product group benefits that result from resource-sharing among related as well as unrelated members of the colony. Such cooperative behaviour can lead to unexpected group benefits; there is an increase the inclusive fitness of related members of the colony (namely kin) and can have direct benefit when shared with unrelated members (namely non-kin). Sharing can also provides by-product benefits when individuals have a shared (or group) interest.Our study focuses on the contrast in the group estimates between sharing and non-sharing populations. For constant ecological resources, sharing behaviour can increase the sustainable population size, increase the total resource stored in the population, and reduce the average resource required per individual, compared to a non-sharing population. (The extent of the increase or decrease will depend on the parameters of the model). This increased carrying capacity due to resource sharing can increase the fitness of individuals in the group. The increase in cooperativity has a nonlinear effect on group benefits: Substantial group benefits are shown only after a cooperativity threshold, and it increases exponentially to a maximum thereafter.