蜂密度和寄主卵密度对玉米螟赤眼蜂寄生效能的影响

在实验室内以米蛾卵作寄主研究了蜂密度和寄主密度对玉米螟赤眼蜂寄生效能的影响。在第一个试验中，1、2、4和8头1日龄的玉米螟赤眼蜂雌蜂被分别接入400粒米蛾卵上，结果表明，卵的总寄生率在最高蜂密度(8头)时显著高于其他蜂密度，但平均每头雌蜂的寄生率却随蜂密度的增加而减少，当蜂密度从1增加到8头时，平均每头雌蜂的寄生率几乎减少了近一半，同时每雌产后代数也随蜂密度的增加而减少，说明蜂密度的增加降低了玉米螟赤眼蜂的寄生效能．另一试验中，50、100、200和400粒米蛾卵上分别接入1头1日龄的赤眼蜂雌蜂，结果表明，随寄主卵密度的增加，卵的总寄生率也显著增加，寄主卵密度每增加1梯度，每雌产后代数平均增加了2倍，由此可以看出，寄主卵密度的增加对玉米螟赤眼蜂的寄生效能有增强作用。

Effect of host and parasite density on Trichogramma ostrinae

The effects of host and parasite density on the efficiency of the egg parasite, Trichogramma ostrinae Pang et Chen were studied in the laboratory under controlled conditions. In the first experiment, females of T. ostrinae of one day old were exposed at different densities i.e. 1, 2, 4, and 8 heads to the 400 eggs of Corcyra cephaloica. Total parasitism was significantly higher at the 8. Also in the same way more than 3-fold increase in the number of female progenies was recorded, when the parasite density destudied by exposing groups of 50, 100, 200 and 400 eggs of Corcyra cephaloica to a single couple of parasite of one day old. Here the parasitism by T. ostrinae exhibited the opposite trend than the 1st experiment. In this case when the host density was raised from with the host density. It was concluded that increasing host density had beneficial effect on parasite efficiency of T. ostrinae.