Mate replacement is costly to males in the multibrooded house sparrow: An experimental study

Abstract

In species that raise several broods within a breeding season, mate replacement may be costly to males if breeding success is low for newly formed pairs. Alternatively, males could benefit from mate replacement if the new female is in better physical condition than the previous mate. Female House Sparrows (Passer domesticus) experimentally handicapped during their first breeding attempt were replaced more frequently than control females. Among females that changed mates, handicapped females remated less successfully than did control females. Relative to control males, males that mated with handicapped females took longer to produce a second clutch. Males that changed mates had shorter relaying intervals but raised fewer fledglings in the following breeding attempt than males that retained mates. These results suggests that mate replacement is costly to males. Courtship rate was positively correlated with male badge size, an indicator of male quality and status, but it was not correlated with any indicator of female quality or female reproductive investment. Increased levels of courtship between two breeding attempts correlated with more rapid laying by replacement females but did not affect the probability of mate replacement or the relaying interval of the original mates. These results suggest that male courtship between clutches may function as a time-saving mechanism when mate replacement occurs.