Parasite removal and its impact on behavior and reproduction in a social African ground squirrel

In the social species of ground-dwelling sciurids, females live in cohesive, matrilineal social groups. There are many suggested benefits of such cohesive groups, yet in some species of sciurids, reproductive success declines with increased group size. Although resources are the ultimate constraint on group size, parasitism is another more proximate factor that can determine reproductive strategies. We tested the hypothesis that parasites influence behavior in a highly social species of African ground squirrel by experimentally manipulating parasite loads. We trapped and marked all animals in 14 social groups. In addition to the regular handling and measurements, all individuals in seven of the groups were treated for both ecotoparasites (using Frontline) and endoparasites (using ivermectin). Parasite counts were estimated by removing ectoparasites with a flea comb and using fecal floats for endoparasites. We predicted that parasite load would increase with group size, that female body mass would increase after treatment, and that time spent grooming and allogrooming would decrease. Our data support the hypothesis that parasites significantly affect the behavior of this species.