Instituto Agroforestal Mediterráneo, Universidad Politécnica de Valencia, Camino de Vera s/n 46022 Valencia, Spain.
Ecol Appl. 2010 Jun;20(4):1101-13. doi: 10.1890/09-1662.1.
The introduced parasitoid wasp Aphytis melinus, the most widespread natural enemy of the California red scale (Aonidiella aurantii) and the superior competitor, has displaced the native Aphytis chrysomphali from most citrus areas of the Mediterranean basin and other citrus areas all over the world. However, our extensive survey data on the scale parasitoid populations collected in 2004-2008 show that in large citrus areas of eastern Spain both parasitoids coexist. Using field data from 179 orchards spatially divided in five citrus-producing agroecosystems, we examined the mechanisms that could explain displacement or coexistence between both Aphytis species in relation to weather conditions. The distribution and abundance of the parasitoid species are related to the mean summer and winter temperatures and relative humidity of each ecosystem. The relative proportion of A. melinus is higher during the warm months, and the abundance of A. chrysomphali increases from south to north, being higher in the cooler northern areas. Aphytis melinus has displaced A. chrysomphali from hot and dry areas, whereas regions with mild summer temperatures and moderate relative humidity present the optimal conditions for the coexistence of the two parasitoids. The more negative effects of winter temperatures on A. melinus allow the earlier use of the available host resource in late winter and spring by A. chrysomphali and the coexistence of both parasitoids in the same orchard via temporal niche partitioning. We combine previous literature on the behavior of Aphytis species in the laboratory under different temperature and humidity conditions with our field results to confirm the role of spatiotemporal weather conditions and seasonal changes in host stages on the variation of Aphytis relative abundance and parasitoid coexistence.
引入的寄生蜂蚜小蜂（Aphytis melinus）是加利福尼亚红蚧（Aonidiella aurantii）最广泛的天敌和优势竞争者，它已将本地的蚜小蜂（Aphytis chrysomphali）从地中海盆地和世界各地的大部分柑橘产区排挤出去。然而，我们在 2004-2008 年收集的有关蚧壳虫寄生蜂种群的广泛调查数据显示，在西班牙东部的大型柑橘产区，这两种寄生蜂共存。利用从 179 个果园收集的田间数据，这些果园在五个柑橘生产农业生态系统中空间划分，我们研究了可能解释两种蚜小蜂在与天气条件有关的情况下的替代或共存的机制。寄生蜂的分布和丰度与每个生态系统的夏季和冬季平均温度和相对湿度有关。A. melinus 的相对比例在温暖的月份较高，而 A. chrysomphali 的丰度从南向北增加，在较凉爽的北部地区较高。A. melinus 已将 A. chrysomphali 从炎热和干燥地区排挤出去，而夏季温度温和、相对湿度适中的地区为两种寄生蜂共存提供了最佳条件。冬季温度对 A. melinus 的负面影响更大，使得 A. chrysomphali 能够更早地在冬末和春季利用可用的宿主资源，并且两种寄生蜂可以在同一个果园中通过时间生态位分离共存。我们将蚜小蜂种在不同温度和湿度条件下的实验室行为的先前文献与我们的田间结果结合起来，以确认时空天气条件和宿主阶段季节性变化对蚜小蜂相对丰度变化和寄生蜂共存的作用。
