Maturation of the Male Pales Weevil (Coleoptera: Curculionidae) Reproductive System and its Effect on Male Response to Females

Male pales weevils, Hylobius pales (Herbst), were sexually immature upon emergence from their pupal cells. During the first 2 wk of adult life the concentration of sperm bundles in the testes increased, and a lumen containing a granular material began to form in the accessory glands. Most individuals had active sperm when 2 wk old. Four-week-old males had a large concentration of sperm bundles, numerous active sperm, and accessory glands entirely filled with a granular material. During mating trials 3to 6-d-old (prereproductive) males did not transfer sperm to either reproductive or prereproductive females. Twenty percent of the 11to 15-d-old (incipient reproductive) males transferred some sperm to reproductive females, but no sperm was transferred to prereproductive females. Eighty-five percent of the 4-wk-old (reproductive) males transferred sperm to reproductive females. The quantity of sperm transferred was quite variable. Seventy percent of the reproductive males transferred small amounts of sperm to prereproductive females. Female receptivity may influence the amount of sperm transferred by reproductive males.