本土寄生蜂对移殖天敌昆虫泽兰实蝇的寄生

泽兰实蝇（Procecidochares utilis Stone）是我国入侵杂草紫茎泽兰的专食性天敌昆虫。为摸清本土寄生蜂对泽兰实蝇的寄生情况，在云南昆明市选取林下和开阔地等两种生境，分别采用对角线五点取样法与邻接格子取样法，调查了紫茎泽兰的生长及感染虫瘿情况；通过饲养与解剖虫瘿，观察了寄生泽兰实蝇的本土寄生蜂种类及其寄生率。结果表明，共有6种寄生蜂从虫瘿中羽化，对虫瘿的寄生率达70％以上；其中大部分虫瘿被3种寄生蜂寄生。虽然在开阔地生境中紫茎泽兰株高和每株枝条数显著大于林下生境，植株和枝条感虫（瘿）率也显著高于林下，但寄生蜂对虫瘿的总寄生率、各种寄生蜂的寄生率在两种生境之间差异不显著。解剖表明，每虫瘿羽化出的寄生蜂数随虫瘿横径的增大而显著增多。

Parasitism of Native Parasitoids on Procecidochares utilis Stone (Tephritidae, Diptera), a Biocontrol Agent against the Invasive Exotic Weed Eupatorium adenophorum Spreng (Compositae) in Southwest China

To investigate the native parasitoid guild attacking the fruit fly,Procecidochares utilis Stone(Tephritidae,Diptera),an introduced biocontrol agent against the exotic crofton weed Eupatorium adenophorum(Compositae) in southwest China,we took samples of galls induced by the fruit fly from two habitats,the open field and forest,and reared half of the samples for emergence of the fruit fly or parasitoids and dissected another half for parasitism.Six species of solitary parasitoids emerged from galls with a combined parasitism of over 70%, among which three parasitoids,Torymoides kiesenwetteri(Mayr),Bracon sp.and Eurytoma trypeicola Zerova,accounted for most of the parasitism.Even though E. adenophorum grew better(as measured by plant height and number of branches) and the infestation rate of galls was higher in the open field than in the forest, the parasitism of each parasitoid and total parasitism did not significantly differ between two habitats.The number of emerged parasitoids per gall increased significantly with the gall size as measured by the horizontal diameter of galls.