Development of Geocoris varius and G. proteus (Hemiptera: Geocoridae) provided with Ephestia kuehniella (Lepidoptera: Pyralidae) eggs

We studied the development of Geocoris varius (Uhler) and Geocoris proteus Distant reared on Ephestia kuehniella Zeller eggs at 20, 24, 26, 30, 33, or 36 °C. The lower developmental thresholds ( T 0 ) and the thermal constants ( K ) of eggs and nymphs of G. varius were 13.3 °C, 151.1 degree-days and 13.4 °C, 433.0 degree-days, respectively; those of G. proteus were 16.1 °C, 98.3 degree-days and 16.9 °C, 226.9 degree-days, respectively. The hatch rate of G. varius eggs was significantly lower at 33 °C than at ≤30 °C, and no eggs hatched at 36 °C. That of G. proteus was lowest at 20 °C and did not decline significantly at 36 °C. The survival rate throughout the nymphal period increased with temperature up to 30 °C in G. varius , and it was lowest at 20 °C in G. proteus . Thus, the optimal rearing temperatures for immature stages appear to be about 24–30 °C for G. varius and 26–33 °C for G. proteus . It might be possible to improve the efficiency of their mass production by controlling the rearing temperature in the above ranges. This would also make the developmental stages of nymphs more uniform and so prevent cannibalism in mass rearing.