FEMALE ROLE IN SPERM STORAGE IN THE RED FLOUR BEETLE, TRIBOLIUM-CASTANEUM

This study clarifies the role of female-controlled processes contribut ing to sperm storage in the red flour beetle, Tribolium castaneum. Evi dence presented indicates that sperm motility is not affected by extre me hypoxia produced by anesthetization of the female with either carbo n dioxide or nitrogen. Sperm location and motility in low-oxygen envir onments did not differ from that of sperm in reproductive tracts immer sed in fully aerated saline. Sperm motility was unaffected by exposure to potassium cyanide, an aerobic respiratory system poison, but was i nhibited by exposure to iodoacetic acid, a glycolysis poison. Based on the retention of sperm motility under extreme hypoxia, female control over sperm storage was then examined. Both anesthetized females and d ead females had fewer stored sperm after mating than unanesthetized co ntrol females. These results suggest that female T. castaneum play an active role in moving sperm from the site of deposition into storage. (C) 1998 Elsevier Science Inc. All rights reserved.