Role of water and moisture in diapause development (A review)

Ivo Hodek

doi:10.14411/eje.2003.037

Abstract

While observational studies led to the assumption that water or moisture (W/M) is a prerequisite for diapause development, the experimental research indicates rather the opposite: usually W/M is needed as late as for the post-diapause resumption of morphogenesis. Recent examples for this type of regulation of dormancy are given: Eggs of the tettigoniid Stictophaula armata, eggs of the grasshopper Oedaleus senegalensis, adults of the bruchid Bruchidius atrolineatus, adults of the endomychid Stenotarsus subtilis (= S. rotundus). In the late diapause of the noctuid Busseola fusca and in eggs of the chrysomelid Homichloda barkeri, moisture is assumed to be the diapause terminating cue. Fall in temperature is assumed decisive for termination of pupal diapause in the saturniid Schausiella santarosensis, although the effect of intense rain after a long dry period has not yet been excluded. Effects of intense changes in environmental conditions and of gradual decrease in diapause intensity with time have often been neglected.

Highlights

Most studies of seasonal ecology of insects focus on photoperiod and temperature as principal regulating cues (Tauber et al, 1986; Danks, 1987)
Photoperiod has an essential role due to the high reli ability of its precise repetition year after year, moisture should not be underestimated - as was rightly indicated by Tauber et al (1998)
The principal function of diapause is to assure syn chronization of these two phenomena. These facts repre sent the basis for a widely accepted assumption that moisture or water (M/W) is the factor regulating the development of such diapauses that are in some way related to alternation of periods of drought and high humidity

Summary

Introduction

Most studies of seasonal ecology of insects focus on photoperiod and temperature as principal regulating cues (Tauber et al, 1986; Danks, 1987). These facts repre sent the basis for a widely accepted assumption that moisture or water (M/W) is the factor regulating the development of such diapauses that are in some way related to alternation of periods of drought and high humidity.

Results

Conclusion