The effect of experimental male removals on extrapair paternity in the wheatear, Oenanthe oenanthe

To examine the role of the pair male in ensuring paternity in the wheatear, we removed pair males for 24 h during the fertile period (days 0 to +1 in 1992 and days -5 to -1 in 1993, where day 0 = first egg date). Control male s were removed during incubation. The frequency and duration of intrusions, and the frequency of extrapair copulations (EPCs), increased during remova ls in the fertile period, but not during incubation. The frequency of extra pair paternity (EPP) was marginally higher (25%) in experimental than contr ol broods and the presence of the pair male seemed particularly important i n ensuring paternity in those days immediately preceding laying. Females we re selective over which males they copulated with in the absence of their m ate and rejected the majority of attempted EPCs. Only extrapair males in be tter body condition than the removed pair male eventually gained successful matings. Experimental males in poorer body condition were also more likely to have EPP in their brood than experimental males in better body conditio n. Female copulatory behaviour was the most important factor in determining patterns of paternity, and mate-guarding behaviours by the pair male appea red to limit the females' opportunities to engage in EPCs by reducing the f requency and duration of intrusions, rather than to control female behaviou r directly. (C) 1999 The Association for the Study of Animal Behaviour.