A genetic analysis of the fission-fusion roosting behavior of tree-roosting maternity colonies of big brown bats (Eptesicus fuscus)

In Cypress Hills Interprovincial Park, Saskatchewan, Canada, tree-roosting big brown bats (Eptesicus fuscus) exhibit fission-fusion roosting behavior and are philopatric to one of three non-overlapping roosting areas. Bats switch roost trees and potentially roost-mates about every two days, and bats appear to have preferred roost-mates. To assess whether genetic relationships mediate fission-fusion behavior in tree-roosting bats, I combined genetic analyses (microsatellite loci and mitochondrial DNA) with behavioral studies. First, I determined whether female philopatry produced genetic subdivision among the roosting areas. Second, I examined roosting associations within one roosting area to determine whether roost-mate decisions were based on genetic relationships. I found that female-mediated gene flow was restricted between roosting areas while male-mediated gene flow was not. Roosting associations were not influenced by genetic relationships. Mating and dispersal behavior of E. fuscus generate group members that are generally not closely related, and bats do not preferentially roost with closely related or matrilineal females. Thus, kin selection is an unlikely explanation for preferred roost-mates, group stability, and cooperation in tree-roosting E. fuscus."--Abstract from author supplied metadata