THE RELATION BETWEEN COLONY SIZE, BREEDING DENSITY AND ECTOPARASITE LOADS OF ADULT EUROPEAN BEE-EATERS (MEROPS APIASTER)

The numbers of chewing lice were determined for adult bee-eaters and r elated to different measures of breeding density. Bee-eaters are infes ted by three species of chewing lice (Meropoecus meropis, Meromenopon meropis and Brueelia apiastri). Meropoecus meropis is the most common species and 94% of all adult bee-eaters were infested. This species al so shows a significant variation between colonies. namely, infestation rate increases with colony size. Using different measures to describe colony size, a stepwise regression analysis showed that inter-nest di stance is the best predictor for ectoparasite load. Average-infestatio n rate per individual decreased significantly with increasing inter-ne st distance. This relationship was even more pronounced for the maximu m number of parasites found within a colony and with the variation in parasite load among members of a colony (controlling for number of bre eding pairs). There was no difference in ectoparasite load between the sexes and no general patterns related to the position of the breeding site within the colony.