Evaluating the fitness of hybrids can provide important insights into genetic differences between species or diverging populations.We focused on surface-and cave-ecotypes of the widespread Atlantic molly Poecilia mexi...Evaluating the fitness of hybrids can provide important insights into genetic differences between species or diverging populations.We focused on surface-and cave-ecotypes of the widespread Atlantic molly Poecilia mexicana and raised F1 hybrids of reciprocal crosses to sexual maturity in a common-garden experiment.Hybrids were reared in a fully factorial 2 x 2 design consisting of lighting(light vs.darkness)and resource availability(high vs.low food).We quantified survival,ability to realize their full reproductive potential(i.e.,completed maturation for males and 3 consecutive births for females)and essential life-history traits.Compared to the performance of pure cave and surface fish from a previous experiment,F1s had the highest death rate and the lowest proportion of fish that reached their full reproductive potential.We also uncovered an intriguing pattern of sex-specific phenotype expression,because male hybrids expressed cave molly life histories,while female hybrids expressed surface molly life histories.Our results provide evidence for strong selection against hybrids in the cave molly system,but also sug-gest a complex pattern of sex-specific(opposing)dominance,with certain surface molly genes being dominant in female hybrids and certain cavemollygenes beingdominant in malehybrids.展开更多
Although the majority of studies on mate choice focus on female mate choice, there is growing recognition of the role of male mate choice too. Male mate choice is tightly linked to 2 other phenomena： female competiti...Although the majority of studies on mate choice focus on female mate choice, there is growing recognition of the role of male mate choice too. Male mate choice is tightly linked to 2 other phenomena： female competition for males and ornamentation in females. In the current article, I review the existing literature on this in a group of fishes, Poeciliidae. In this group, male mate choice appears to be based on differences in female quality, especially female size, which is a proxy for fecundity. Some males also have to choose between heterospecific and conspecific females in the unusual mating system of the Amazon molly. In this case, they typically show a preference for conspecific females. Whereas male mate choice is relatively well documented for this family, female ornamentation and female competition are not.展开更多
Choosing a mate is likely one of the most influential decisions any individual makes because it heavily influences their fitness. Going back all the way to the seminal work by Darwin （1871, 1859）, we mostly think of...Choosing a mate is likely one of the most influential decisions any individual makes because it heavily influences their fitness. Going back all the way to the seminal work by Darwin （1871, 1859）, we mostly think of females as choosing mates, whereas males compete over mating opportunities with females. This view is very well supported, but somewhat incomplete. As Darwin struggled to find a good explanation for the existence of ornamental traits in males, he proposed Sexual Selection and along with that theory he suggested 2 mechanisms that could lead to and maintain such extreme traits： Female Choice and Male Competition. Historically, male competition was quickly accepted, whereas acceptance of female choice was delayed until much later, coinciding with the rise of modern feminism （Zuk 1993）.展开更多
基金supported by the National Science Foundation of America(DEB-0743406)the OU VP for Research Faculty Investment Program.
文摘Evaluating the fitness of hybrids can provide important insights into genetic differences between species or diverging populations.We focused on surface-and cave-ecotypes of the widespread Atlantic molly Poecilia mexicana and raised F1 hybrids of reciprocal crosses to sexual maturity in a common-garden experiment.Hybrids were reared in a fully factorial 2 x 2 design consisting of lighting(light vs.darkness)and resource availability(high vs.low food).We quantified survival,ability to realize their full reproductive potential(i.e.,completed maturation for males and 3 consecutive births for females)and essential life-history traits.Compared to the performance of pure cave and surface fish from a previous experiment,F1s had the highest death rate and the lowest proportion of fish that reached their full reproductive potential.We also uncovered an intriguing pattern of sex-specific phenotype expression,because male hybrids expressed cave molly life histories,while female hybrids expressed surface molly life histories.Our results provide evidence for strong selection against hybrids in the cave molly system,but also sug-gest a complex pattern of sex-specific(opposing)dominance,with certain surface molly genes being dominant in female hybrids and certain cavemollygenes beingdominant in malehybrids.
文摘Although the majority of studies on mate choice focus on female mate choice, there is growing recognition of the role of male mate choice too. Male mate choice is tightly linked to 2 other phenomena： female competition for males and ornamentation in females. In the current article, I review the existing literature on this in a group of fishes, Poeciliidae. In this group, male mate choice appears to be based on differences in female quality, especially female size, which is a proxy for fecundity. Some males also have to choose between heterospecific and conspecific females in the unusual mating system of the Amazon molly. In this case, they typically show a preference for conspecific females. Whereas male mate choice is relatively well documented for this family, female ornamentation and female competition are not.
文摘Choosing a mate is likely one of the most influential decisions any individual makes because it heavily influences their fitness. Going back all the way to the seminal work by Darwin （1871, 1859）, we mostly think of females as choosing mates, whereas males compete over mating opportunities with females. This view is very well supported, but somewhat incomplete. As Darwin struggled to find a good explanation for the existence of ornamental traits in males, he proposed Sexual Selection and along with that theory he suggested 2 mechanisms that could lead to and maintain such extreme traits： Female Choice and Male Competition. Historically, male competition was quickly accepted, whereas acceptance of female choice was delayed until much later, coinciding with the rise of modern feminism （Zuk 1993）.
