Laboratory of Entomology, Wageningen University, Wageningen, The Netherlands.
PLoS One. 2011;6(7):e20870. doi: 10.1371/journal.pone.0020870. Epub 2011 Jul 12.
Females of the larval parasitoid of Drosophila, Asobara citri, from sub-Saharan Africa, defend patches with hosts by fighting and chasing conspecific females upon encounter. Females of the closely related, palearctic species Asobara tabida do not defend patches and often search simultaneously in the same patch. The effect of patch defence by A. citri females on their distribution in a multi-patch environment was investigated, and their distributions were compared with those of A. tabida. For both species 20 females were released from two release-points in replicate experiments. Females of A. citri quickly reached a regular distribution across 16 patches, with a small variance/mean ratio per patch. Conversely, A. tabida females initially showed a clumped distribution, and after gradual dispersion, a more Poisson-like distribution across patches resulted (variance/mean ratio was closer to 1 and higher than for A. citri). The dispersion of A. tabida was most probably an effect of exploitation: these parasitoids increasingly made shorter visits to already exploited patches. We briefly discuss hypotheses on the adaptive significance of patch defence behaviour or its absence in the light of differences in the natural history of both parasitoid species, notably the spatial distribution of their hosts.
来自撒哈拉以南非洲的果蝇幼虫寄生蜂 Asobara citri 的雌性会通过战斗和追逐同种雌性来保护其寄生的宿主，而亲缘关系较近的、古北界的 Asobara tabida 则不进行巢区防御，且经常在同一巢区同时搜索。本研究调查了 A. citri 雌蜂的巢区防御对其在多巢区环境中分布的影响，并将其与 A. tabida 的分布进行了比较。在重复实验中，每个实验从两个释放点释放了 20 只雌蜂。A. citri 雌蜂很快在 16 个巢区之间达到了稳定的分布，每个巢区的方差/均值比都很小。相反，A. tabida 雌蜂最初表现出聚集分布，在逐渐分散后，在巢区之间形成了更类似于泊松分布的模式（方差/均值比更接近 1，且高于 A. citri）。A. tabida 的扩散很可能是一种开发利用的效应：这些寄生蜂对已被利用的巢区的访问次数逐渐减少。我们简要讨论了关于巢区防御行为的适应性意义或其缺失的假说，这与两种寄生蜂物种的自然历史差异有关，特别是它们宿主的空间分布。
