THE PHYSIOLOGY OF DORMANCY IN THE SWEETCLOVER WEEVIL

Abstract

The physiology of the overwintering adult stage of Sitona cylindricollis (Fahr.), the sweetclover weevil, has been examined. It has been shown that the dormancy is characterized by a drop in oxygen consumption, a cessation of development in the reproductive organs, and a slight rise in fat content; and that the termination of dormancy is characterized by a reversal of these conditions. The water content does not change. Although the total respiration exhibited the characteristic U-shaped curve from entry into dormancy until its cessation, the CO-insensitive respiration remained at a low level throughout. Termination of the dormancy requires a period of exposure to low temperatures. It is concluded that this dormancy is not essentially different from diapause in immature insects.