Stark J D, Vargas R I, Walsh W A
Department of Entomology, Washington State University, 98371, Puyallup, WA, USA.
Agricultural Research Service, USDA, HI, USA.
Oecologia. 1994 Nov;100(1-2):196-199. doi: 10.1007/BF00317147.
We studied an imported host-parasitoid community in Hawaii, asking to what extent the species covaried in a systematic fashion even though all species were exotic to Hawaii, and occurred in an artificial agroecosystem (a commercial guava, Psidium guajava L., orchard). Using knock-down pyrethrin sprays we were able to accurately quantify numbers of the host, [oriental fruit fly, Bactrocera dorsalis (Hendel)] and its four major parasitoid species [Biosteres arisanus (Sonan), Diachasmimorpha longicaudata (Ashmead), Psyttalia incisi (Silvestri), and Bi. vandenboschi (Fullaway)] at hourly intervals. We found that the parasitoids' activity and abundance was well correlated with the activity and abundance of their host, and that all four parasitoid species covaried in concert with one another. In fact, the magnitude of correlation between the different species in this system was greater than the correlation with temperature. This show clearly that an entirely exotic community, reassembled piecemeal as a result of biocontrol efforts, can end up with patterns of temporal covariation that are highly coincident. One other interesting result concerns the speed with which sprayed trees were recolonized by the fruit fly and its parasitoids. The time that it took each species to reach its mean density prior to removal by the first pyrethrin spray at 0600 hours varied. It took 2 h for female B. dorsalis to recolonize guava trees to pre-spray levels. It took 3 h for Bi. arisanus, 4 h for D. longicaudata, 7 h for Bi. vandenboschi and 14 h for P. incisi to reach pre-spray levels. The fact that Bi. arisanus recolonized vacant trees almost as rapidly as did the fruit fly pest suggest that there is little opportunity for the fruit fly to escape in space and time by "staying one step ahead of its enemies".
我们研究了夏威夷一个外来的寄主 - 寄生蜂群落，探究即便所有物种对夏威夷来说都是外来物种，并且它们存在于一个人工农业生态系统（一个商业番石榴果园，番石榴学名Psidium guajava L.）中，这些物种在多大程度上以一种系统的方式共同变化。通过使用击倒性除虫菊酯喷雾，我们能够每隔一小时准确量化寄主（东方果实蝇，学名Bactrocera dorsalis (Hendel)）及其四种主要寄生蜂物种（阿里山潜蝇茧蜂，学名Biosteres arisanus (Sonan)；长尾潜蝇茧蜂，学名Diachasmimorpha longicaudata (Ashmead)；切割潜蝇茧蜂，学名Psyttalia incisi (Silvestri)；以及范登博希潜蝇茧蜂，学名Bi. vandenboschi (Fullaway)）的数量。我们发现寄生蜂的活动和丰度与它们寄主的活动和丰度密切相关，并且这四种寄生蜂物种彼此之间也协同变化。实际上，该系统中不同物种之间的相关程度大于与温度的相关性。这清楚地表明，一个完全由外来物种组成的群落，由于生物防治努力而逐步重新组合，最终可能呈现出高度一致的时间协变模式。另一个有趣的结果涉及果蝇及其寄生蜂重新定殖被喷洒树木的速度。每种物种在早上6点第一次除虫菊酯喷雾去除之前达到其平均密度所需的时间各不相同。雌性东方果实蝇重新定殖番石榴树到喷雾前水平需要2小时。阿里山潜蝇茧蜂需要3小时，长尾潜蝇茧蜂需要4小时，范登博希潜蝇茧蜂需要7小时，切割潜蝇茧蜂需要14小时才能达到喷雾前水平。阿里山潜蝇茧蜂几乎与果蝇害虫一样迅速地重新定殖空树，这一事实表明果蝇几乎没有机会通过“比其天敌领先一步”在空间和时间上逃脱。
