Meeting Abstract

128.5  Monday, Jan. 7  Resistance and tolerance in invasive and native songbirds in Kenya: evidence of parasite spillback COON, CAC*; BRACE, AJ; MARTIN, LB; Univ. of South Florida, Tampa; Univ. of South Florida, Tampa; Univ. of South Florida, Tampa ccoon@mail.usf.edu

Avian malaria is more prevalent in invasive house sparrows (Passer domesticus) compared to native passerines in recently invaded Kenya (<60 years). We sought to determine whether this finding was due to different immunological strategies between invasive house sparrows and native songbirds. Therefore, we experimentally infected house sparrows and native congeners, grey-headed sparrows (Passer griseus), with endemic coccidia, in Nakuru, near the edge of the ongoing range expansion of house sparrows in Kenya. We hypothesized that house sparrows would be more parasite tolerant (i.e. hosts mitigate negative fitness consequences associated with infection) and less parasite resistant (i.e. hosts actively prevent or clear parasites) as compared to native birds. While there was no statistical evidence of differences in tolerance between the two species, exposed house sparrows shed over 12 times as many infectious coccidia oocysts as native grey-headed sparrows. Such high levels of shedding likely have very important effects on parasite prevalence in invaded communities and may be indirectly helping house sparrows to compete with native songbirds and establish in new territories.