QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by DEAN, R. L. Articles by HARTLEY, J. C. Search for Related Content PubMed Articles by DEAN, R. L. Articles by HARTLEY, J. C.

Journal of Experimental Biology 66,173-183 (1977)
Published by Company of Biologists 1977

EGG Diapause in Ephippiger Cruciger (Orthoptera: Tettigoniidae) : I. The Incidence, Variable Duration and Elimination of the Initial Diapause

R. L. DEAN ¹ and J. C. HARTLEY ²

¹ Department of Zoology, University of Nottingham, England; Department of Zoology, University of Western Ontario, London, Canada.
² Department of Zoology, University of Nottingham, England

Eggs of the bush-cricket Ephippiger cruciger may be subject to two periods of diapause during the course of embryogenesis. After oviposition not all eggs develop at temperatures favourable to morphogenesis, some cease activity at the unsegmented embryonic primordium stage. If these eggs are cooled for 10-30 days some develop on subsequent exposure to higher temperatures, but further prolongation of the cooling period does not render more eggs competent to develop. Although cooling for longer than the critical period does not affect the proportion of eggs which subsequently start to develop, it does affect the time within which reactivated eggs begin to develop. The delay in the initiation of development after cooling increases with the duration of the chilling period. Excessively long cooling periods, however, impair the eggs' ability to complete embryogenesis. It is evident that eggs laid in one season will develop and hatch over a number of years.