Data from: Infection with Haemoproteus iwa affects vector movement in a hippoboscid fly – frigatebird system

Haemosporidian parasites, which require both a vertebrate and invertebrate
host, are most commonly studied in the life stages occurring in the
vertebrate. However, aspects of the vector's behavior and biology can
have profound effects on the parasite dynamics. Here we explore the
effects of a haemosporidian parasite, Haemoproteusiwa, on a hippoboscid
fly vector, Olfersiaspinifera. Olfersiaspinifera is an obligate
ectoparasite of the great frigatebird, Fregata minor, living among bird
feathers for all of its adult life. This study examines the movements of
O. spiniferabetween great frigatebird hosts. Movement, or host-switching,
was inferred by identifying host (frigatebird) microsatellite
genotypesfrom fly bloodmeals that did not match the host from which the
fly was collected. Such host-switches were analyzed using a logistic
regression model, and the best-fit model included the H. iwa infection
status of the fly and the bird host sex. Uninfected flies are more likely
to have a bird genotype in their blood meal that was different from their
current host's genotype (i.e., to have switched hosts) than infected
flies. Flies collected from female birds were more likely to have switched
hosts than those collected on males. Reduced movement of infected flies
suggests that there may be a cost of parasitism for the fly. The effect of
host sex is likely driven by differences in the sex ratio of bird hosts
available to moving flies.