Laboratory Mating Behavior of the Alfalfa Weevil,Hypera postica

Male Hypera postica (Gyllenhal) (Coleoptera: Curculionidae) in the laboratory were extremely aggressive, mounting females as often as 10 times in 12 hours. Prior to mounting, males displayed no detectable courtship behavior. After attaining the copulatory position (male on top, male venter to female dorsum), the male generally patted the female‗s head and prothorax with his antennae and simultaneously extended the aedeagues. The female was usually receptive, and copulations lasted up to 12 hours, though most were of much shorter duration. The male frequently spent considerable time merely riding the female, sometimes with the aedeagus extended but not inserted. When females were unreceptive they repelled males by running rapidly through foliage, weak kicking or rubbing with the hind legs, pressing their venters against the substratum, or raising the abdominal tip under the elytra. Virgin females may also possess internal mechanisms such as exserting the ovipositor to prevent insertion of the aedeagus. Previous mating experience seemed to increase female receptiveness, while young virgins sometimes required considerable stimulation by males before copulating. The sexes were at least partially attracted to each other by vision. Males did not seem to immediately recognize females or even members of their own species and readily mounted other male alfalfa weevils as well as 3 other species of curculionids. Males frequently disturbed mounted pairs and sometimes mounted mating males, resulting in columns of weevils up to 6 high. Males sometimes mounted and inserted the aedeagus into dead females, and on 1 occasion a male repeatedly copulated with a female whose head and prothorax had been broken off by his persistent mating activities. After copulation the male sometimes elevated the tip of his abdomen, often with the aedeagus still extended, and a white, viscous substance was observed. The substance may have been semen and the elevated position a means of facilitating retraction of the aedgeagus.