Handicapped males and extrapair paternity in pied flycatchers: a study using microsatellite markers

We report an attempt to induce extrapair copulations and fertilizations in a species with a low intensity of sperm competition, the pied flycatcher Ficedula hypoleuca. Shortly after pair formation males were made less attractive to females by removing certain wing and tail feathers. Earlier research has shown that this manipulation reduces a male's pairing success. The idea was to test whether females mated to such males (N= 9) were more likely to obtain extrapair fertilizations than females mated to unmanipulated controls (N= 9). Paternity testing was carried out on all 98 young in the 18 broods, using a set of six microsatellite markers isolated from the species. Extrapair fertilizations were revealed in only three (17%) broods; two broods of handicapped males and one of a control male. A total of seven (7%) offspring were not genetically related to their putative father, a level which agrees well with results of other studies of this and other populations. We conclude that there was no evidence to suggest that the fertilization pattern was altered by the experimental manipulation. One reason for the lack of response could be that female mate choice in this species is based on male phenotypic, and not genotypic, quality.