Ectoparasites Increase the Cost of Reproduction in their Hosts

Parasites are hypothesized to increase the cost of reproduction in their hosts due to their time and energy drain. I experimentally studied the effects of the haematophagous tropical fowl mite (Ornithonyssus bursa, Berlese (Macronyssidae, Gamasida)) on the within-season costs of reproduction in their swallow (Hirundo rustica L.) hosts by simultaneously manipulating (i) the size of first clutches (which were either increased by one egg, kept as a control, or decreased by one egg), and (ii) the mite loads of first clutch nests (nests were either sprayed with a pesticide or kept as controls). The experimental treatments were successful as evidenced from the effect of the clutch size manipulation on clutch and subsequent brood size, and from the effect of the parasite manipulation on subsequent mite loads