Sexual colouration and sperm traits in guppies

The relationships among the area, hue, saturation and brightness Of orange colouration and sperm traits in the guppy Poecilia rcticulata were investigated. Males with greater areas of orange colouration had significantly larger sperm loads. more motile sperm and longer sperm relative to males with relatively little orange colouration. Males with greater areas of orange colouration did not possess more viable sperm than males with relatively little orange colouration. There was no evidence that any of the sperm traits were related 10 the hue, saturation or brightness of the orange colouration. These results are discussed fit the context of the roles that direct and indirect selection might play in maintaining female preference for male guppies With large areas of orange colouration. (c) 2007 The Authors Journal compilation (c) 2007 The Fisheries Society of the British Isles.