Sexual selection is a process that occurs when a non-random relationship exists between trait variation and an individual’s reproductive success (MacLellan et al., 2009). In addition, sexual selection has been recognized as a major force in the evolution and maintenance of male polychromatism in guppies (Kodric-Brown, 1985). However, sexual selection acts on a range of traits including those associated with intrasexual competition effort and thus selection against deleterious mutations may be excluded due to traits other than those subject to mating preferences (Whitlock & Agrawal, 2009). It presumes that all females were equally benefited by mating with a certain male that involved with additive genetic effect (Evans & Magurran, 2000).
The complex interactions among traits that are subject to sexual selection in guppies are evident from Farr’s (1980) experiments on the effects of female choice on male reproductive success. He inferred his results as suggesting that male courtship activities predominate the effect of colour pattern and brightness with the result that females preferred dull, vigorously displaying males to bright and sluggish ones. However, the sperm competition or by female cryptic choice can be achieved thru courtship behaviour (Eberhard, 1996; Zeh & Zeh, 1997; Birkhead, 1998).
The models of Zahavi (1975), Andersson (1982), Kodric-Brown and Brown (1984) and Nur and Hasson (1984) propose that females select male traits that accurately reflect the overall genetic fitness of males. It is advantageous for females to select males with traits that contribute to survival and reproduction, but are not related just to courtship and mating, because inheritance of these attributes will benefit both male and female offspring. Patterns of mate choice in relation to male attributes can provide insight into the underlying processes of sexual selection and help to resolve the current controversy.