Effect of photoperiod and temperature on the ovarian development of the white-spotted stink bug, Eysarcoris ventralis (Heteroptera: Pentatomidae)

The ovarian development, copulation and oviposition of the white-spotted stink bug, Eysarcoris ventralis, were studied in relation to photoperiod and temperature. The ovary developed under photoperiods over 14L-10D. Photoperiods shorter than 13L-11D inhibited the ovarian development. This species diapaused by the effect of short day in the same way as adults with nondeveloped ovary. For the ovarian development of the diapausing autumn population, long day (over 13L-11D) and high temperature (over between 15 and 20°C) were required. The copulation was usually observed under conditions similar to those required for the ovarian development. Short day treatment did not affect further oviposition of the females, but oviposition was discontinued or the number of eggs laid under low temperature reach as 15°C decreased significantly. Oosorption appeared to occur in the females which did not complete oviposition. However, when the females were placed under favourable conditions oviposition resumed. The females which had laid eggs in the previous year could be traced in the field population of early spring