DNA-based genetic mating systems of four co-distributed colonially breeding waterbirds.

CAROLINA ISABEL MIÑO; ANDIARA SILOS MORAES DE CASTRO E SOUZA; SÍLVIA NASSIF DEL LAMA

Cuzco

Congreso; IX Congreso de Ornitologia Neotropical, VIII Congreso Peruano de Ornitologia; 2011

Neotropical Ornithological Society, Sociedad Peruana de Ornitologia

Colonially breeding waterbirds are an interesting group in which to characterize genetic mating systems. However, conventional parentage analyses are precluded in this group due to the complexity in capturing reproductive adults. We identified parents of relatedness amongst nestlings belonging to the same broods in four Neotropical waterbirds co-distributed in Brazil: the Wood Stork (n=194 pairs, 122 nests, 8 colonies), the Roseate Spoonbill (n=14, 82 nests, five colonies) and the Great Egret (n=69, 53 nests, four colonies) and the White-faced Ibis (n=105 pairs, 80 nests, one colony). We used genotypic information on microsatellites, pairwise-relatedness estimates, maximum-lielihood pedigree reconstruction, hypothesis testing and pedigree reconstruction methods. We identified kiship patterns using a conservative agreement approach, for about 14% of Wood Stork broods, 25% of Roseate Spoonbill broods, 43% of White-faced Ibis broods and 36% of Great Egret broods. Only full-siblings were found in Great Egret broods, while both unrelated nestlings and halfsibs were present in broods of the remaining species. Our results suggest the genetic monogamy is the prevalent mating system in Great Egrets, whereas both extra-pair paternity and intraspecific brood parasitism can be present in the rest of the examined species. Differences in the timing and duration of the breeding cycles, as well as in the degree of parental care, are discussed as possible explanations of the differences observed between species. This study contributes to gaining insights into unseen aspects of the reproductive behavior of colonially breeding waterbirds. In addition, we settle the base for methodological approach to study parentage in species with elusive adults.