Female guppies use orange as choice cue: a manipulative test

Female guppies from a feral South African population respond sexually to more orange males in correlative trials. We impaired the female's ability to use orange elements of male colour patterns by conducting choice trials under orange light. Under orange light, there was no relationship between male colour pattern and female sexual response, but under white and blue light treatments there was such a relationship. Other male ornaments were not preferred by females either under normal lighting conditions or when their ability to use orange as a cue was impaired. The implications for sexual selection theory and the evolution of multiple male ornaments are discussed