title: Sibling competition and the evolution of prenatal development rates.
abstract: Sibling competition has been proposed as an important evolutionary pressure driving interspecific variation in developmental rates. We tested this hypothesis using rates of extra-pair paternity and brood parasitism, as well as the degree of hatching asynchrony, as indices of sibling competition in a comparative analysis of 70 species of bird. We found mixed support for the influence of sibling competition on prenatal development. Brood parasitism was negatively correlated with the length of incubation, and hatching asynchrony was positively correlated with the length of incubation, but both correlations disappeared when phylogeny was controlled for. Extra-pair paternity, however, was negatively correlated with incubation length even when phylogeny was controlled for. The latter could represent support for the influence of sibling competition on prenatal development or indirect effects of correlated selection on both traits by adult mortality. The existence of these correlations demonstrates that life-history strategies include linkages among a larger suite of traits than previously recognized.
authors.affiliation: Montana Cooperative Wildlife Research Unit, University of Montana, Missoula, MT 59812, USA. jlloyd@selway.umt.edu
authors.forename: John D
authors.initials: JD
authors.lastname: Lloyd
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Martin
mesh_terms: D000818:Animals; D005075:Biological Evolution; D001717:Birds / Q000145:classification / Q000196:embryology* / Q000469:parasitology; D003163:Competitive Behavior; D004625:Embryo, Nonmammalian / Q000196:embryology; D008954:Models, Biological; D010063:Ovum / Q000254:growth & development; D010802:Phylogeny; D035781:Siblings; D013045:Species Specificity; D013997:Time Factors