GEOGRAPHIC-VARIATION IN BODY SIZE AND ITS RELATION TO THE MATING STRUCTURE OF TETRAOPES POPULATIONS

Adult milkweed beetles (genus Tetraopes) are shown to exhibit geographical variation in the intensity of stabilising selection on body size. This is related in both sexes to inter-locality variation in the amount of intrapopulational variability present in this character. Mean size of female beetles also varies geographically. A model of the selection process is proposed that would select against migration between locally differentiated populations and preserve the partitioning of genetic variation among these populations. © 1979 The Genetical Society of Great Britain.