Effects of photoperiod on development and demographic parameters of the predatory thrips Scolothrips longicornis fed on Tetranychus urticae.

The effect of five photoperiods (0:24, 6:18; 12:12, 18:6, and 24:0 light:dark (L:D)) on the development, reproduction, and survival of the predatory thrips Scolothrips longicornis Priesner fed on the two-spotted spider mite, Tetranychus urticae Koch, was tested under laboratory conditions at 60% RH and 25 degrees C. Development time of almost all immature stages in S. longicornis was the shortest under long day lengths (18:6 and 24:0 L:D). The adult duration of both sexes decreased with increasing light length from 6 to 24 h. The longevity of male and female decreased with increasing light length. Under a 12:12 L:D photoperiod, S. longicornis females had the longest oviposition period and longevity, highest net reproductive rate (R0 = 15.37), intrinsic rate of natural increase (r = 0.141), and finite rate of increase (lambda = 1.151). Life table parameters showed a significant difference with various photoperiods. The consequences of the present research demonstrated that a 12:12 L:D photoperiod is the most favorable for the reproduction and development of S. longicornis fed on T. urticae, and that for mas rearing for augmentative biological control programs, would be the ideal photoperiod to maximize production.