Ecological Study on the Occurrence of the Yellow-spotted Longihorn Beetle (Psacothea hilaris PASCOE)

I. Effects of Temperature and Photoperiodic Conditions on their Development

Abstract

The larvae of the yellow-spotted longihorn beetles obtained as Tsukui in Kanazawa pref. were reared aseptically on an artificial diet under varied temperatures and photoperiodic conditions. The larvae rapidly developed at 30°C and reached the last instar in 40 days after hatching, regardless the long day (16hr light and 8hr dark) or shoft day (8hr light and 16hr dark) treatments. In 25°C rearing, the larvae treated by the long day condition became the adults in 50 to 150 days after hatching. On the other hand, they took 270 to 370 days under the short day treatment. In 20°C rearing the adults emerged scatteringly during 100 to 290 days under long day and during 200 to 300 days under short day. The larval period in 15°C rearing was the longest of all temperature rearings and thus it took 250 to 350 days from hatching to emergence in either long day or short day treatment. The pupal period became longer gradually as the temperature was lowered and under short day than under long day. The body length and weight of the adult under short day were longer and heavier than those under long day.