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Abstract

Differences in male morphology and mating behaviors are thought to confer species sexual isolation between sailfin and shortfin species of mollies. This study used interspecific crosses between the sailfin molly, P. latipinna, and the shortfin molly, P. mexicana, to investigate patterns of inheritance of morphological traits and behavioral rates of three mating behaviors in F1 hybrid males. The two parental species showed clear species differences with respect to the length of the dorsal fin and dorsal fin ray number. First generation hybrid males were intermediate between the two parental species for dorsal fin length and fin ray number, suggesting autosomal control of this trait with little effect of dominance by genes from either parental species. Parental species showed clear species differences in their rates of courtship displays. Unlike the pattern for dorsal fin morphology, F1 hybrid males showed a clear distinction in display rates with respect to the direction of the interspecific cross. Male hybrids whose sires were P. latipinna had courtship display rates that were up to three times higher than the rates of displays performed by hybrid males whose fathers were P. mexicana. The distribution of phenotypes between the parental species and that of hybrid males sired by that parental species was nearly identical. Such a pattern suggests the influence of Y-linked genes on the inheritance of courtship display rates in mollies.

Sexual selection against natural hybrids may contribute to reinforcement in a house mouse hybrid zone

“…Mating signals evolve under sexual and ecological selection [13]. Their complexity depends on the number and characteristics of the genes involved in their determinism [14][15][16], as well as on environmental factors influencing their expression and their perception [13,17]. Hybrid genotypes could produce unrecognized or unattractive signals when new associations of alleles are brought together by hybridization [18], and sexual selection can occur against such signals (review in the electronic supplementary material, S1).…”

Discriminating males alter sperm production between species

“…4 and 5), and very few studies have addressed the importance of male mate choice or male behaviors in promoting sexual isolation (for exceptions, see refs. [7][8][9][10]. One type of system in which it is particularly interesting to study male choice and sexual isolation is species assemblages that consist of both bisexual as well as unisexual, gynogenetic species.…”

First confirmed record of an established population of sailfin molly, Poecilia latipinna (Actinopterygii: Cyprinodontiformes: Poeciliidae), in Europe

“…And third, these three species are often hybridised by breeders to create new strains for the ornamental trade (Balon 2004, Fosså 2004. These strains may be viable and fertile (Sterba 1973, Ptacek 2002, Balon 2004 and may display confusing patterns of morphological variation. Despite these difficulties, we were able to identify the Vouliagmeni molly as the true sailfin molly, P. latipinna, using the number of scales around caudal peduncle as the principal diagnostic character.…”