Variation in extra-pair paternity in Tachycineta swallows: evolutionary history and current ecology

FERRETTI VALENTINA; MASSONI, VIVIANA; BULIT, FLORENCIA; LILJESTHROM, MARCELA; LOVETTE, IRBY J.; WINKLER, DAVID W.

Campos do Jordao

Congreso; Symposium talk in “Harnessing the power of research networks to reveal and contrast avian life cycle patterns and life history evolution.” 25th International Ornithological Congress; 2010

We explore here the genetic mating system of five species in the swallow genus Tachycineta residing in North, Central and South America (T. bicolor, T. thalassina, T. albilinea, T. leucorrhoa and T. meyeni) using the Golondrinas de las Americas network. Tachycineta swallows show high variation in genetic breeding system, ranging from one of the highest rates found in any socially monogamous passerine in T. bicolor—with extra-pair young in up to 89% of nests—to substantially lower rates in T. albilinea—with extra-pair young in 26% of nests. These striking differences in mating system make this genus a model group for studying diversification of life history strategies and extra-pair paternity in birds in a phylogenetic context. Likewise, the broad distribution of the Tachycineta genus can help us untangle other contributing ecological factors. Thus, we test the relationship between extra-pair paternity and increased opportunities for finding extra-pair mates by exploring the effects of current ecological variables such as nest density and synchronous breeding on paternity. We found white-rumped swallows to have 78% of nests with extra-pair young, Chilean swallows to have 12% of nests with extra-pair young and violet-green swallows to have extra-pair young in 75% of nests. Neither current ecological factors nor evolutionary history were good predictors for the observed variation in genetic mating system. We discuss our results in light of life history theory.