Endogenously entrained emergence and oviposition rhythm in the African rice gall midge, Orseolia oryzivora H. and G. (Dipt., Cecidomyiidae)

Studies on the rate, period and cycle of emergence and oviposition of Afric an rice gall midge, Orseolia oryzivora kept in screenhouses revealed an end ogenously entrained circadian rhythm. Emergence commenced 23 days after inf estation (at 27 +/- 2 degreesC and 70 +/- 12% relative humidity) at 1800 h and stopped at 2400 h daily for a 5 day period of emergence. Each female ma ted once throughout life and oviposition occurred after mating between 1800 h and 2400 h daily. This 6 h cycle of oviposition continued until the ovip ositing female died.