In Australia Fopius arisanus (Sonan) is an established, but exotic fruit fly egg-larval-pupal parasitoid which co-occurs with Diachasmimorpha kraussii (Fullaway), a native larval-pupal fruit fly parasitoid: both attack the native fruit fly Bactrocera tryoni (Froggatt). In interactions involving evolutionary novel host-parasitoid associations, F. arisanus consistently out-competes other parasitoid species, including D. kraussii. However, in fruit fly-parasitoid systems where there is co-evolutionary history between parasitoids and their hosts, competitive hierarchies can vary. In this study we investigated the outcome of competition between F. arisanus and D. kraussii within B. tryoni, to test whether the close evolutionary relationship between D. kraussii and B. tryoni might circumvent the competitive advantage of F. arisanus. Consistent with previous research, and despite the evolutionary relationship, dissection of multiparasitized B. tryoni larvae showed that D. kraussii was invariably suppressed by F. arisanus. A total of 47% and 74% of the eggs of D. kraussii in presence of F. arisanus were killed within a span of 24 h and 48–72 h, respectively. However, parasitoid emergence from fruit fly hosts exposed sequentially to F. arsianus and D. kraussii suggest that D. kraussii females are able to discriminate hosts already parasitized by F. arisanus. Results show that the co-evolutionary relationship between B. tryoni and D. kraussii does not help overcome the early-acting advantage of the egg parasitoid F. arisanus. Though F. arisanus may not have completely displaced D. kraussii in its native habitat, simultaneous inundative releases of these two parasitoid species (currently under consideration) might not help increase B. tryoni parasitism levels.

在澳大利亚Fopius arisanus（Sonan）是既定的，但奇异的果蝇卵，幼虫，蛹期寄生与同现Diachasmimorpha毛虫（Fullaway） ，原生的幼虫-蛹实蝇寄生：两种攻击本土果蝇昆士兰实蝇（ Froggatt）。在涉及进化的新型寄主-拟寄生虫协会的相互作用中，Arisanus不断竞争其他拟寄生虫物种，包括D. kraussii。但是，在果蝇类寄生生物系统中，寄生生物与其宿主之间存在共同进化的历史，竞争等级可能会有所不同。在这项研究中，我们调查了F. arisanus与D.毛虫内B.昆士兰，测试之间的密切进化关系是否D.毛虫和B.昆士兰可能规避的竞争优势F. arisanus。与先前的研究相一致，尽管进化关系，multiparasitized的解剖B.昆士兰幼虫表明D.毛虫是无一例外地抑制F. arisanus。共有47％和虫卵74％D.毛虫中的存在F. arisanus物的分别为24小时，48-72小时，一个跨度内杀死。然而，寄生果蝇从依次暴露于F. arsianus和D. kraussii表明D. kraussii雌性能够区分已经被F. arisanus寄生的寄主。结果表明，Tryoni和D. kraussii之间的共同进化关系无助于克服卵寄生性无花果F. arisanus的早期作用优势。尽管阿里桑种的F. arisanus可能尚未完全取代其本地生境中的D. kraussii，但同时寄生这两种寄生性物种的释放（目前正在考虑中）可能无助于增加B. tryoni的寄生性。