Relationship between Cold Hardiness and Diapause

Abstract

Cold hardiness and diapause are both essential components of winter survival for most insects of the temperate zone. But, in many cases, it is not clear how these two are related. Are they independent events or is cold hardiness a component of the diapause syndrome? Both independence (Lees, 1955; Salt, 1961; Ring, 1972) and dependence (Asahina, 1969; Mansingh, 1971, 1974) of cold hardiness and diapause have been defended vigorously, and indeed evidence for both possibilities can be found in the literature. In this chapter I argue that cold hardiness can be achieved independently of diapause, but cold hardiness is often a component of the diapause syndrome and the expression of diapause frequently extends the insect’s capacity to cold harden.