Extra-Pair Copulation-Seeking Behavior in Purple Martins, Progne subis subis: The Relatedness Hypothesis

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Abby Amanda Stanley (Creator)
The University of North Carolina at Greensboro (UNCG )
Web Site: http://library.uncg.edu/
Malcolm Schug

Abstract: Although socially monogamous, both male and female Purple Martins, Progne subis subis, seek extra-pair copulations (EPCs) resulting in multiple-sired broods (Morton 1990; Wagner et al. 1996). Although numerous studies have attempted to explain this behavior, evolutionary mechanisms are not yet known. For this reason I assessed the genetic relatedness hypothesis using microsatellite genotypes derived from a colony of Purple Martins in Severna Park, Maryland from 1993. Although I predicted that all extra-pair offspring would be sired by adult males after their second year of age, extra-pair paternity was not confined to older males. I further predicted that older males sing to attract related subadult males. However there was no evidence that adult males were recruiting related subadults to achieve indirect genetic benefits. I also predicted that females with multiple-sired brood paired to related males seek EPCs leading to extra-pair fertilizations in an attempt to genetically diversify their broods. I found no evidence that avoiding related males was the motive behind EPC-seeking behavior in females. I also predicted that exclusively monogamous females would be less related to their social mate in comparison to polyandrous females. However, there was no significant difference in relatedness between the two.

Additional Information

Language: English
Date: 2008
Purple Martins, Progne subis subis, extra-pair copulations (EPCs), evolutionary mechanisms, genetic relatedness, microsatellite genotypes
Purple martin $x Sexual behavior.
Purple martin $x Reproduction.
Sperm competition.
Sexual selection in animals.

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