Initial diapause and embryonic development in the speckled bush-cricket, Leptophyes punctatissima

ABSTRACT. The initiation and pattern of embryonic development in Leptophyes punctatissima (Bosc) (Tettigoniidae) are shown to be variously dependent on temperature. Immediate high temperature (30°C) facilitated rapid and direct embryogenesis to the stage of diapause in the fully formed embryo. Slightly lower temperature (25°C) resulted in a delay before embryogenesis started, and this delay was greatly extended as an initial diapause if incubation temperatures were decreased (20-16°C). Still lower initial temperatures (8–12°C) facilitated subsequent development at 20–30°C. These responses all increased as a function of exposure time. Once initiated, the rate of development was temperature dependent, but competence to tolerate high temperature, and ability to continue development at low temperatures, changed with age. In general, the developmental temperature range appears to be lowered with age. None of these different treatments had any effect on the late embryonic diapause. According to the temperatures prevailing at oviposition, Leptophyes could be an annual or a biennial species; the biennial pattern is normal.