MALE MATE PREFERENCES IN A GYNOGENETIC SPECIES COMPLEX OF AMAZON MOLLIES

Female Amazon mollies, Poecilia formosa, are gynogenetic and mate with males of a sexual species, P. latipinna or P. mexicana, for successfu l reproduction. It was found that both species of males are able to di stinguish between conspecific females and Amazon mollies, and preferen tially mate with the former. Male mate preference per se is not an evo lved response to avoid mating with Amazon mollies; male P. latipinna t hat are from populations currently allopatric with Amazon mollies also prefer conspecifics. The strength of this preference, however, is str onger in P. latipinna from populations sympatric with Amazon mollies t han in P. latipinna from populations that are allopatric with the gyno gen, suggesting that reproductive character displacement in mating pre ferences has occurred. Male size did not influence mating decisions; t hus, the hypothesis was rejected that the gynogens are usually mated b y smaller, younger males, which have yet to learn to discriminate betw een females. Unlike some previous studies, it was shown that P. mexica na can discriminate between conspecific females and Amazon mollies, al though the strength of preference might be weaker in P. mexicana than in P. latipinna. Male P. latipinna and P. mexicana differed in their c hoices between females of the two heterospecific species in the comple x. Male P. latipinna were reluctant to mate at all when given a choice between the two heterospecific females, P. mexicana and P. formosa. P oecilia mexicana males, alternatively, showed high mate attraction to P. formosa when these females were paired with P. latipinna females. T his result is intriguing, given that it is thought that female P. mexi cana and male P. latipinna were involved in the original hybridization event that gave rise to P. formosa. Therefore, the strong attractiven ess of P. formosa to P. mexicana may be related to a maternally derive d genetic component. (C) 1996 The Association for the Study of Animal Behaviour