Parental roles in the White Spoonbill (Platalea leucorodia): the sperm competition hypothesis

Full article

Published:

Volume 41(1), June 1994. Pages 19-28.

Language:

English

Keywords:

Doñana, parental roles, Platalea leucorodia, sperm competition, White Spoonbill.

Abstract:

Contributions by male and female White Spoonbills (Platalea leucorodia) to nest building, incubation, brooding, nest attendance and chick feeding were studied in the breeding population of Doñana National Park (SW Spain). Males were mainly responsible for obtaining nest material, and during daylight they incubated and attended the nest more than females. Females incubated and attended the nests at night and fed the chicks at a higher rate than males. With the exception of nest building behaviour, these results were expected under the hypothesis that in colonial birds for which the risk of sperm competition is high, mating effort through extra-pair copulations has selected for higher parental contributions by males than by females to activities that do not require males to leave their nests, the sites where all copulations take place. By contrast, in those colonial species for which there is a low risk of sperm competition, mainly as a consequence of effective resistance by paired females during extra-pair copulation attempts (e.g. gulls and colonial raptors), the sexual patterns of nest attendance and chick feeding are the opposite to those described in the Spoonbill. This is probably the result of an early specialization, in the evolutionary history of these species, of males for gathering food for their mates during the prelaying and laying periods. This is a common feature in these species, that coevolved with the resistance of the paired females to extra-pair copulation attempts and, therefore, with the absence of sperm competition.