Factors Determining Mating Frequencies in Some New World Butterflies and Skippers1

The mean insemination frequencies of 14 species of New World skippers and butterflies were determined by means of spermatophore counts. Each sample of females was divided into 4 age categories on the basis of structural criteria. The complex relationships among mean insemination frequencies, intrinsic effects of genetically controlled behavior, and the extrinsic effects of population dynamics are discussed. Particular attention is given to the effects of age (mortality), female receptivity, population density, unusual reproductive patterns, and sexual selection.