补充寄主提高林间松毛虫卵寄生率的研究

研究表明:在松林内,14种松毛虫卵寄生蜂中有9种能寄生柞蚕卵。利用柞蚕卵作为马尾松毛虫卵寄生蜂的补充寄主是可行的。补充寄主的林地,卵蜂种群密度比对照提高0.68～1.43倍,而长年补充又比阶段补充增加1.37倍,比对照区增加2倍。林间补充寄主后提高了平腹小蜂和白角小蜂的种群密度。第一代松毛虫卵期总寄生率补充寄主区较对照区提高5.16～28.96％,第二代提高3.62～24.97％;第三代提高8～17.99％。根据卵蜂在不同生态条件下的消长规律,补充寄主的方法应有所不同,在地被物稀少的松林中补充寄主的次数应多一些,而在地被物丰富的松林中,补充寄主的次数可相应减少。

ENHANCEMENT OF EGG PARASITIZATION OF DENDROLIMUS PDNCTATU8 [LEP.:LASIOCAMPIDAE] BY SUPPLIMENTING HOST EGGS IN THE FOREST

Qf the 14 major egg parasitoids of the pine caterpiller, D.punetatus. 9 can make use of the oak silkworm, Antheraea pernvi as the alternative host in Hunan Province. Experiments on supplying oak silkworm eggs to the forest resulted in an 0.68-1.4 fold increase of the overall population density of the parasitoids comparing to that of the control. When A.pernvi eggs were supplied 3 times per month throughout the year, the parasitoids' population density was 1.37 times higher than in the forest where egg suppliments were made twice in the month before the appearance of D.punctatus eggs. A 5.16-28.96%, 3.62-24.97%, and 8-17.99% increase in the egg parasitization of the first, second, and third generation D.punctatus. respectively, was found in the host egg supplimented forest. Different methods of supplimenting host eggs are suggested for forests of different ecological characteristics. More frequent suppliments of host eggs are needed for the forests with less vegetation coverage.