Circadian rhythm of egg hatching in Triatoma infestans (Hemiptera: Reduviidae).

The timing of hatching of Triatoma infestans (Klug) eggs was analyzed by means of time-lapse photography. Under a photoperiod of 12:12 (L:D) and constant darkness, maximum eclosion occurred at the end of the subjective night. Under constant light, the rhythmicity disappeared. Hatching rhythm seems to be maintained by a circadian endogenous oscillator. By hatching close to dawn, when relative humidity is high, insects may avoid excessive water loss.