The 3rd instar nymphs of L. striatellus attacked by H. atratus were immedietly reared at 15℃, 20℃, 25℃ and 30℃ under 16 hours lighting.
The developmental period of H. atratus from the egg to the adult emergence was 117.1 days at 15℃, 43.3 days at 20℃, 23.8 days at 25℃ and 20.2 days at 30℃. The developmental period had a remarkable difference between 15℃ and 20℃, but it showed a little difference between 25℃ and 30℃.
There was a large fluctuation in the developmental velocity of parasites when they were in the host. The 3rd instar of host nymphs, attacked by the parasite, can grow up to be a 5th larvae or adults ; and the parasite larvae hatched from the host adult required longer developmental period than those from the 5th instar larvae.
The regression equation of developmental velocity from the egg to the adult emergence was shown by Y=0.0028X-0.0322, developmental zero was 11.5℃ and thermal constant was 357.2 degree-days. If the generations of parasite are caluculated using the develop mental zero, the themal constant, and the mean temperature in Matsue, it has 5 generations in a year.