Sexual Dimorphism and Morphonietric Differences in the Eastern, Western, and Egyptian Alfalfa Weevils1,2

Abstract

The shape of the last abdominal tergite and sternite was the best diagnostic character for determining the sex of adult alfalfa weevils, Hypera postica (Gyllenhal) (Coleoptera: Curculionidae), from both the eastern and western United States, and the Egyptian alfalfa weevil, H. bruneipennis (Boheman). Differences were observed also between the sexes of the eastern alfalfa weevil with regard to the elytral stripe, body size and proportions, position in which the front legs are held at rest, and manner of movement. Body size and proportions also differed significantly between the sexes in the western and Egyptian alfalfa weevils. Body proportions without regard to sex differed significantly among the 3 groups with proportions in the Egyptian alfalfa weevil intermediate between the eastern and western alfalfa weevils.