The influence of environmental factors on dormancy and duration of egg development inMetrioptera roeseli(Orthoptera: Tettigoniidae)

✍ Scribed by Sigfrid Ingrisch

• Publisher: Springer-Verlag
• Year: 1984
• Tongue: English
• Weight: 530 KB
• Volume: 61
• Category: Article
• ISSN: 0029-8549
• DOI: 10.1007/bf00396769

✦ Synopsis

Developing eggs of Metrioptera roeseli HGB. have an obligate "embryonic" diapause in stage 23 and a facultative "initial" diapause in stage 4. Initial diapause is lacking when the ovipositing females are kept at long day photoperiod (LD 16/8), but is induced at LD 14/10 and LD 8/16. When natural light conditions are given in the laboratory, the females mostly lay diapausing eggs from the end of August onwards. In eggs without initial diapause, a larger number of embryos reach a stage, in which the embryonic diapause can be broken by chilling, only at favorable temperature (4 weeks at 24°C or 8 at 18°C) and in contact with water before the first winter. Thus, some individuals of a given population of M. roeseli have an annual, others a biennial life cycle. The variability in the duration of egg development is due to a photoperiodically induced, facultative initial diapause and to a possible quiescence caused by insufficient temperature and/or moisture.