Entomology Department, North Dakota State University, Fargo, ND, USA.
Exp Appl Acarol. 2011 Nov;55(3):233-48. doi: 10.1007/s10493-011-9468-y. Epub 2011 May 20.
Predatory mites are important components of subterranean food webs and may help regulate densities of agricultural pests, including western corn rootworms (Chrysomelidae: Diabrotica virgifera virgifera). Implementing conservation and/or classical biocontrol tactics could enhance densities of specialist or generalist predatory mites and lead to pest suppression, but first relevant mite species must be identified and their predatory capabilities evaluated. We conducted lab assays to quantify consumption of immature rootworms and oviposition rates of various mite species. Our study indicates that rootworms are a sub-optimal food source for the mite taxa tested. However, all mite species fed upon rootworms to some degree, although consumption by nematophagous Eviphis ostrinus was extremely low. Predators consumed more rootworm larvae than eggs, and mite size was correlated with prey consumption, with larger predators eating more prey. Four mite taxa (Gaeolaelaps sp., S. miles, Gl. americana, and G. aculeifer) had detrimental effects on survival of rootworm larvae, and the latter two species also had negative impacts on densities of pest eggs. Although it is unlikely that any of these mite species by itself has a major impact on rootworm control, the community of generalist soil-dwelling mites may play an important role in regulating immature rootworm populations in the field.
捕食性螨虫是地下食物网的重要组成部分，可能有助于调节农业害虫的密度，包括西部玉米根虫（Chrysomelidae：Diabrotica virgifera virgifera）。实施保护和/或经典生物防治策略可以提高专食性或广食性捕食性螨虫的密度，并导致害虫受到抑制，但首先必须识别相关的螨虫物种，并评估其捕食能力。我们进行了实验室测定，以量化各种螨虫物种对不成熟的根虫的消耗和产卵率。我们的研究表明，根虫是测试的螨虫类群的次优食物来源。然而，所有的螨虫物种都在某种程度上以根虫为食，尽管食线虫Eviphis ostrinus 的消耗量极低。捕食者消耗的根虫幼虫多于卵，而螨的大小与猎物消耗有关，较大的捕食者吃更多的猎物。有四种螨类（Gaeolaelaps sp.，S. miles，Gl. americana 和 G. aculeifer）对根虫幼虫的存活有不利影响，后两种物种对害虫卵的密度也有负面影响。尽管这些螨虫物种本身不太可能对根虫的控制产生重大影响，但土壤中普遍存在的螨类群落可能在调节田间未成熟根虫种群方面发挥重要作用。
