van Alphen Jacques J M, Nordlander Göran, Eijs Irene
Department of Population Biology, University of Leiden, P.O. Box 9516, NL-2300 RA, Leiden, The Netherlands.
Division of Forest Entomology, Swedish University of Agricultural Sciences, P.O. Box 7044, S-750 07, Uppsala, Sweden.
Oecologia. 1991 Sep;87(3):324-329. doi: 10.1007/BF00634586.
Decaying petioles of giant hogweed,Heracleum mantegazzianum Sommier & Levier, are used as a breeding site by six species ofDrosophila and the drosophilidScaptomyza pallida. The most numerous parasitoid species associated with this community isLeptopilina australis. BecauseL. australis was previously unknown in western Europe, we present the characters to distinguish it form its close relativeL. clavipes. Experiments on host species selection and survival ofL. australis showed that this parasitoid mainly usesD. limbata as host. Olfactometer experiments showed thatL. australis is attracted by the odour of decaying hogweed stalks, especially when these contain larvae ofD. limbata. L. australis is also strongly attracted by the odour of stinkhorns, a habitat in which it has never been found in nature.D. phalerata is the dominant fly species in stinkhorns, and is not a host ofL. australis. We offer a possible functional explanation for this unexpected habitat choice, by showing thatD. transversa andD. kuntzei, both species found to breed in fungi, are also suitable hosts forL. australis. We also discuss habitat choice with regard to a proposed phylogeny of theLeptopilina species in temperate Europe. Finally, we discuss niche overlap ofL. australis with the otherLeptopilina species.
巨型猪草（Heracleum mantegazzianum Sommier & Levier）腐烂的叶柄被六种果蝇和果蝇科的苍白潜蝇用作繁殖场所。与这个群落相关的寄生蜂种类中数量最多的是南方柔茧蜂（Leptopilina australis）。由于南方柔茧蜂此前在西欧并不为人所知，我们给出了将其与近亲棒状柔茧蜂（L. clavipes）区分开来的特征。关于南方柔茧蜂寄主种类选择和生存的实验表明，这种寄生蜂主要以缘条果蝇（D. limbata）为寄主。嗅觉计实验表明，南方柔茧蜂会被腐烂猪草茎的气味所吸引，尤其是当这些茎含有缘条果蝇幼虫时。南方柔茧蜂也会被鬼笔的气味强烈吸引，而鬼笔是一种它在自然界中从未被发现过的栖息地。指带果蝇（D. phalerata）是鬼笔中的优势果蝇种类，且不是南方柔茧蜂的寄主。我们通过表明在真菌中繁殖的横带果蝇（D. transversa）和孔氏果蝇（D. kuntzei）也是南方柔茧蜂的合适寄主，为这种意想不到的栖息地选择提供了一种可能的功能解释。我们还根据欧洲温带地区柔茧蜂属物种的拟系统发育来讨论栖息地选择。最后，我们讨论了南方柔茧蜂与其他柔茧蜂属物种的生态位重叠情况。
