Uptake and loss of water in diapause and non‐diapause eggs of crickets

Abstract

ABSTRACT. In laboratory‐laid eggs of the striped ground cricket, Allonemobius fasciatus DeGeer (Gryllidae), water absorption occurs at an early stage of embryogenesis (stage II) at 30°C but is delayed until later stages at lower temperatures. This is related to the variation in diapause stage at different temperatures. No egg developed beyond stage VII (the end of anatrepsis) without water absorption. A. fasciatus shows seasonal variation in the stage of water absorption. At 30°C, eggs collected in August absorb water at the early stage while many of those collected in September avert diapause and absorb water at a later stage.Diapause also influenced the water absorption of eggs in A. socius Scudder. Eggs of short‐day females enter diapause and absorb water at stage II, while those of long‐day females develop without diapause and absorb water at a later stage (around stage IV).The susceptibility to desiccation (r.h. 50%) was examined at 20°C with A. fasciatus eggs. The percentage water loss and mortality of eggs varied with the time and duration of exposure to desiccation. Eggs are most sensitive to desiccation during the first several days after being laid and during the period of water absorption.