DIAPAUSE AND QUIESCENCE IN EGGS OF A TROPICAL GRASSHOPPER OEDALEUS-SENEGALENSIS (KRAUSS)

In Mall, eggs of the grasshopper Oedaleus senegalensis enter diapause at the end of September and remain in diapause for 7-8 months; thereaf ter eggs are in a state of quiescence until they are exposed to moist conditions, The developmental arrest supervenes at an anatreptic stage characterized by the appendages being turned inward and downward, Dia pause termination began in April, and 80% of the pods had resumed deve lopment by the end of May, Eggs from individual pods developed simulta neously, and approximately 10% were either infertile or had died durin g development. The eggs possibly absorb water vapor directly from atmo spheric air, and soil moisture as low as 1% was adequate water for sti mulating the egg hatch, Tolerance to water loss was apparently linked to the anatreptic stage; severe drought at other stages of development proved lethal, Diapause favors water concervation, At 5% RH, the wate r content was reduced by only 10% during 11 weeks in diapause eggs whi le nondiapause eggs died within 6 weeks after losing about 70% of thei r water content, At RH ranging from 27 to 62% death from desiccation i n postdiapause, quiescent eggs increased to 50 and 100% respectively i n 3 and 16 months after diapause termination. Copyright (C) 1996 Elsev ier Science Ltd