|Publication Type:||Journal Article|
|Year of Publication:||1996|
|Authors:||D. M. Tompkins, Jones, T., Clayton, D. H.|
|Pagination:||733 - 740|
|Keywords:||biology, bird, Chewing lice, cost, fly, growth, Hippoboscidae, host, lice, louse, parasitism, Phthiraptera, size, survival, virulence|
1. Parasites that are transmitted vertically from parent hosts to offspring are expected to be relatively benign, because their fitness depends on successful host reproduction. The effects of two species of vertically transmitted ectoparasite on the reproductive success of swifts (Apus apus L.) were tested. Populations of the Chewing Louse, Dennyus hirundinis (L.) (Phthiraptera: Menoponidae), and the Flightless Louse Fly, Crataerina pallida (Latreille) (Diptera: Hippoboscidae), were experimentally manipulated, effectively converting the natural aggregated frequency distribution of each species into a bimodal distribution of high and low loads. 2. Neither parasite had any effect on nestling growth or fledging success, even though parasite loads were boosted above natural levels and host environmental conditions were poor during part of the study, thus increasing the chances of detecting an effect of the parasites. 3. In contrast to parasite load, year, brood size and hatch date were all significantly related to components of nestling growth. Year and brood size were also significantly related to fledging success. 4. These results are consistent with theoretical models suggesting that vertically transmitted parasites evolve reduced virulence because they depend on host reproduction for dispersal to new hosts.
Effect of vertically transmitted ectoparasites on the reproductive success of swifts (Apus apus)