Courtship behavior differs between monogamous and polygamous plovers

Courting, accessing, and/or competing for mates are involved in sexual selection by generating differences in mating success. Although courtship behavior should reflect intensity of mating competition and sexual selection, studies that compare courtship behavior across populations/species with different mating systems subject to differing degrees of mating competition are scanty. Here, we compare courtship behavior between two closely related plover species (Charadrius spp.): a polygamous population of snowy plovers and a socially monogamous population of Kentish plovers. Consistently with expectations, both males and females spent more time courting in the polygamous plover than in the monogamous one. In addition, courtship behavior of males relative to females increased over the breeding season in the polygamous plover, whereas it did not change in the monogamous one. Our results therefore suggest that courtship behavior is a fine-tuned and informative indicator of sexual selection in nature.