Polyandrous mating in treetops: how male competition and female choice interact to determine an unusual carnivore mating system

This chapter examines competition in the context of pollination ecology. Competition is typically treated from the perspective of the plants, but it is also likely to occur among and between the pollinators. Furthermore, competition can occur at various levels—as a structuring factor in communities, as a selective force on an individual plant’s phenology, morphology, or rewards, and at a genetic level structuring competition for pollens between males, and female choice between possible mates. The chapter first considers several types of of competition in pollination ecology, potential outcomes of competition, and competition between pollinators before discussing how selection reduces intraspecific competition among plants and competition among pollinators. It also explores paternity, maternity, and gene flow in coflowering communities, focusing in particular on male competition and female choice, along with gene flow via pollen dispersal and seed dispersal.

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Dual functions of a melanin-based ornament in the common yellowthroat

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2005.3053 ◽

2005 ◽

Vol 272 (1568) ◽

pp. 1121-1127 ◽

Cited By ~ 72

Author(s):

Scott A Tarof ◽

Peter O Dunn ◽

Linda A Whittingham

Keyword(s):

Mate Choice ◽

Female Choice ◽

Female Mate Choice ◽

Male Competition ◽

Male Quality ◽

Female Mate ◽

Common Yellowthroat ◽

Mask Size ◽

The Common ◽

Dual Functions

Melanin-based ornaments often function as signals in male–male competition, whereas carotenoid-based ornaments appear to be important in female mate choice. This difference in function is thought to occur because carotenoid pigments are more costly to produce than melanins and are thus more reliable indicators of male quality. We examined the role of melanin- and carotenoid-based ornaments in male–male competition and female choice in the common yellowthroat Geothlypis trichas , a sexually dichromatic passerine. Males display a black facial mask produced by melanin pigmentation and a bright yellow bib (throat, breast and belly) produced by carotenoid pigmentation. In controlled aviary experiments, mask size was the best predictor of both male–male competition and female mate choice, and, therefore, mask size may be regarded as an ornament of dual function. These dual functions may help to maintain the reliability of mask size as an indicator of male quality, despite the potentially low cost of production. The size of the bib was unrelated to male–male competition or female choice, but there was a tendency for females to prefer males with more colourful bibs. We propose that the black mask is important in competition for territories with other males and for attracting females. Our results highlight the need for more studies of the mechanisms of sexual selection in species with ornaments composed of different pigment types.

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