Wirkungen der Fotoperiode und Temperatur auf die Entwicklungsstadien von Acrotylus insubricus Scop. (Orthopt., Acrididae)

Abstract

Effect of photoperiod and temperature on the developmental stages of Acrotylus insubricus Scop. (Orth., Acrididae)

The effect of different temperatures and photoperiods on the developmental stages ofAcrotylus insubricus Scop. was studied. The species has no embryonic or nymphal diapause. The relatively low temperature of the winter months prolonges the incubation period as well as the nymphal development. By rising temperature both eggs and nymphs began to continue their development. The shortest nymphal duration at 27 °C (63.9 days) was obtained when rearing nymphs at long photoperiod (16L:8D), while the longest duration (92 days), was recorded at short photoperiod (8L:16D). In intermediate photoperiod (12L:12D), the nymphal duration was 82.8 days, between the long and the short photoperiods. At 37 °C, the nymphal durations were shorter than at 27 °C and still the shortest at a long day (4310 days) than the two other conditions. The total nymphal mortality was higher at short day-length than that at the other photoperiods tested. The incubation period as well as the percentage of hatching were not affected by the different photoperiodic regimes while the low temperature prolonges the incubation period and nymphal development. The higher temperature (37 °C) tended to mask or abolish the effect of the photoperiod while the moderate temperature (27 °C) clarified this effect when the two factors were combined together.