Abstract
The stink bug, Pyrrhocoris sibiricus, is a ground-dwelling seedfeeder. The effects of temperature and photoperiod on nymphal development and adult body size were investigated under six rearing conditions with different temperature (20, 25 and 30°C) and photoperiod (12L-12D and 16L-8D) regimes. The survival rate in the nymphal stage was higher and the nymphal developmental period was shorter at higher temperatures. Adult body size in terms of body length became larger with increases in temperatures. Adult body size in terms of body length became larger with increases in temperature, and was largest at 30°C under 12L-12D. These results showed that this species is adaptive to high temperatures. In the field, the body size of adults that emerged from mid-August to late September was largest (SAKASHITA, unpublished data). This coincided with the fact that adult body sized was larger at high temperatures under short day length. The nymphal developmental period of this species was shorter under 12L-12D than under 16L-8D at 20°C. It is considered that this leads to completion of nymphal development before the onset of the winter season.
