DEVICHE, P.J.*; GREINER, E.; Arizona St. Univ.; U. Florida Gainesville: Interspecific differences in hematozoan infection in Sonoran desert Aimophila sparrows

We used stained thin blood smears to measure parasite infection prevalence in four conspecific grassland Aimophila sparrows: Rufous-winged (A. carpalis; RWSP), Rufous-crowned (A. ruficeps, RCSP), Cassin�s (A. cassinii, CASP), and Botteri�s (A. botterii, BOSP) sparrows. In other avian species, this prevalence can be sexually dimorphic and age-dependent, be highest during the breeding season, and vary geographically. To account for these factors, we sampled only adult males that were in breeding condition (Jul-Aug) and were caught in a same region (SE Arizona). Some birds of the four species were infected with trypanosomes and microfilaria. In contrast, Haemoproteus fringillae was detected in over 90% RWSP (n=40), but not in RCSP (n=20), CASP (n=40) or BOSP (n=20) although all four species share the same breeding habitat. In other studies, hematozoan infections increased during the reproductive season due to a seasonal relapse associated with breeding and/or to newly acquired infections. This was apparently the case for trypanosomes in RWSP, as infection prevalence with this parasite decreased between summer (42%) and winter (Nov-Jan: 8%, n=21, p=0.04). H. fringillae infection prevalence in RWSP did, however, not decrease seasonally. One reason for this is that once infected with Haemoproteus, RWSP retain this hematozoan chronically. Indeed, viable Haemoproteus gametocytes were detected in 100% male RWSP (n=25) that we held in captivity for one year, when they were not exposed to insect vectors and were shielded from photoperiod and meteorological events in environmental chambers. Similar to adults, free-ranging hatching year male RWSP (n=11) had a high (73%) H. fringillae infection prevalence, showing that birds can acquire this infection during the first months of life.