马尾松毛虫寄生天敌—红尾追寄蝇的生物学研究

红尾追寄蝇是马尾松毛虫幼虫期的重要寄生天敌,主要寄生5～6龄松毛虫,第1、2、3代松毛虫寄生率分别为21.37. 44.95和0.71％。该蝇在湖南年发生5～6代,以蛹在土内越冬。95％以上的卵产于寄主胸足上,每寄主体上的着卵量为1～33粒,最多出蝇11头。当着卵量在7.5～20粒时,寄主陆续在幼虫和蛹期全部死亡;2.5粒时有3％的寄主仍能存活。寄蝇种群数量变动与当年5月气温成正相关,与7年下旬至8月上旬气温成负相关。

BIOLOGY OF EXQRISTA XANTHASPIS [DIP.:TACKINIDAE],AN IMPORTANT PARASITE OF DENDROLIMUS PUNCTATUS

xanthaspis wiedemann has 5-6 generations a year, overwintering in the soil. Percent parasitization of the 1st, 2nd and 3rd generations of D. punctatus by the fly was 21. 37%, 44. 75% and 0.71%, respectively. About 95% of the eggs were laid on the prothoracic legs of the host larvae of advanced instars. The number of eggs per host varies from 1 to 33, with a maximum of 11 eggs hatched. The host would die gradually in its larval or pupal stage, once it received 7-20 eggs of the parasite. But 3% Of the attacked hosts could survive when they had an averaga of 2.5 eggs each. The population fluctuation of E. xanthaspis in fields was found to be positively correlated with the temperature of May, but negatively correlated with that of late July to, early August.