Showing papers by "John A. Endler published in 1995"

Geographic variation in female preferences for male traits in poecilia reticulata.

Abstract: We examined the preferences of female guppies (Poecilia reticulata) from 11 localities in Trinidad with respect to male color-pattern elements, body shape and size, and overall color and brightness contrast. Females are on average more attracted to males from their own population than from alien populations, and populations appear to vary in the criteria used in female choice. Multiple-regression analysis suggests that mate-preference criteria vary among localities in intensity, sign, and the number of traits used. Although preference estimators and color-pattern parameters are unique to each population, only orange, black, and color contrast showed a correlation between degree of male trait and degree of preference for that trait. There is a clear effect of water color and a possible effect of predation intensity. The results are discussed in light of various models of sexual selection and the early stages of speciation.

Multiple-trait coevolution and environmental gradients in guppies.

Abstract: Guppies show geographical variation in many different kinds of traits. Traits covary with each other, with predation and with other environmental factors. Phenotypic correlations are often assumed to result from genetic correlations, but may also result from covariation among different sources of natural selection and interactions among the traits' functions. This network of interactions could bias the direction of evolution in characteristic ways, and suggests how intraspecific variation may give rise to interspecific variation.