Advances in Sexual Selection Theory: Insights from Tropical Avifauna

– Over the last 30 years, sexual selection has become one of the most influential and rapidly growing areas within evolutionary biology and behavioral ecology. Sexual selection has important effects on the evolution of life history traits, mating systems and morphology, and also has been suggested as a factor that promotes speciation. Avian systems have played an essential role as models in the development of sexual selection theory. However, most studies have focused on temperate species, although they account for less than one quarter of avian species worldwide. Therefore, before applying existing theories universally, caution is advised, especially considering latitudinal trends in life history traits and evolutionary strategies. Here, we brought together five tropical bird studies covering different aspects of sexual selection theory. Two studies detail the evolutionary processes involved with plumage signals; one of these deals with the influence of female sensory drive on the evolution of male plumage, and the second investigates how non-random female mate choice can promote genetic introgression along a hybrid zone. A third study examines how sex differences in diet can lead to temporal asynchrony between periods of peak male display activity and female nesting. A fourth study details how differences in lek spatial structure and social organization influence the degree of male reproductive skew among manakins. The fifth study examines differences in the intensity of sexual selection in temperate and tropical taxa and assesses current knowledge regarding the frequency of extra-pair paternity among regions. The contributions of these studies to our current understanding of sexual selection are discussed. Accepted 14 October 2007.