Social and genetic mating system of a Neotropical cooperative breeder, the Baywing (Agelaioides badius).

URSINO, CYNTHIA A.; RIEHL, CHRISTINA; DE MÁRSICO, M. CECILIA; REBOREDA, JUAN CARLOS

Cambridge

Simposio; DNA: Past, Present and Future Symposium; 2015

Harvard University

Social and genetic mating system of a Neotropical cooperative breeder, theBaywing (Agelaioides badius).Cynthia Ursino, Christina Riehl, María Cecilia De Mársico and JuanCarlos Reboreda Cooperatively breeding birds show a multiplicity of mating systems, rangingfrom genetic monogamy to complex patterns of joint-nesting and shared paternitywithin cooperative groups. Determining the extent of reproductive sharing isnecessary to understand the relative importance of direct and indirect componentsof inclusive fitness in driving helping behaviour. We investigated the mating systemof the Baywing (Agelaioides badius),a Neotropical facultative cooperative breeder, using behavioral observations and microsatellite genotyping. In our study population in eastern Argentina, 40% of baywing nests have 1to 6 helpers that join the breeding pair after the eggs hatched, and the number ofhelpers often increases after fledging. Theseobservations suggest that helpers do not share paternity with the dominantbreeding pair and therefore, Baywings are genetically monogamous. To test this idea, we assessed the genotype of 140 nestlings, 16 putative mothers and15 putative fathers from 36 nests using eight DNA microsatellite loci. Our findings show that putative mother is the geneticnestling mother and that extra-pair nestlings are rare in the broods (8%). The results support the hypothesis that Baywings aresocially and genetically monogamous and suggest that helping behavior in thisspecies is maintained by selective forces other than direct breedingopportunities. Keyworkd: Mating system, cooperative breeding, monogamous