Interspecific variation in the size of the nutrient investment made by male butterflies during copulation.

Interspecific comparisons of lepidopteran mating behavior reveal that there is surprisingly little variation in the overall structure of mating behavior from species to species. This apparent lack of strong interspecific differences in behavior suggests minor differences between species in the intensity of sexual selection and therefore that the nutritional investments made by males during copulation are similar from species to species. This paper represents a preliminary effort to test this prediction by comparing the quantities of material passed by males on a per unit body weight basis for 10 species of butterflies that are common in the southern USA.-from Authors