Exposure of non-diapause eggs to low temperature: the effects on egg hatching, nymphal survival, and developmental periods in Trigonotylus caelestialium (Heteroptera: Miridae)

Abstract

We exposed non-diapause eggs of the rice leaf bug Trigonotylus caelestialium to a low temperature (4°C) and investigated the effects on hatching, nymphal survival, and developmental periods with a view to obtaining many newly hatched nymphs or newly emerged adults on the same day. When eggs were stored at a constant temperature of 25°C, 54.1% of nymphs and 50.9% of adults emerged on the 7th day and the 20th day after collecting them for 24 h, respectively. The hatching rates of eggs exposed to the low temperature for 7, 10, and 13 day were significantly lower than that of eggs maintained at 25°C. However, compared to the non-exposure group, only a small decrease in the hatching rate was observed in the 4-d exposure group (8.1%). Further, exposing the eggs to the low temperature did not affect the survival of the nymphs to adult emergence or the developmental periods. These results suggest that the exposure of eggs to the low temperature for 4 d or less should be a simple and useful method for obtaining many nymphs and adults on the same day.