Berndt Oliver, Meyhöfer Rainer, Poehling Hans-Michael
Institute of Plant Diseases and Plant Protection, University of Hannover, Herrenhaeuser Str. 2, D-30419 Hannover, Germany.
Exp Appl Acarol. 2003;31(1-2):1-14. doi: 10.1023/b:appa.0000005108.72167.74.
In biological control programmes, the two predatory soil mites Hypoaspis aculeifer and H. miles are often applied against soil-borne pests like mushroom flies, springtails and mites. Although the mites show high consumption rates on varying prey types in Petri dish experiments and in greenhouses, their overall efficiency is sometimes limited. We hypothesized that intraspecific interactions, like cannibalism, could contribute to this decreased competence. Therefore, experiments were conducted to show the propensity of H. aculeifer and H. miles to cannibalise. Adult mites and nymphs were introduced as predators with conspecific eggs, larvae, nymphs, adult females or males as prey and the number of killed individuals was recorded. Additionally, the oviposition rate on conspecific prey was quantified and the correlation with the number of prey consumed was calculated to assess the influence of cannibalism on egg production. The results illustrate that cannibalism occurs infrequently in both Hypoaspis spp., the only exception being H. aculeifer nymphs, which cannibalised one conspecific egg per day. Moreover, cannibalism never occurred in the presence of alternative prey. Oviposition rate decreased during the experiment in both species but it was positively correlated with the cannibalism rate only for H. aculeifer. The benefit of cannibalism for populations of H. aculeifer and H. miles is discussed.
在生物防治计划中，两种捕食性土壤螨类——尖狭下盾螨和迈氏下盾螨，常被用于防治诸如菇蝇、跳虫和螨类等土传害虫。尽管在培养皿实验和温室中，这些螨类对不同类型猎物的捕食率很高，但其整体效率有时却很有限。我们推测，种内相互作用，如同类相食，可能导致了这种能力的下降。因此，开展了实验以探究尖狭下盾螨和迈氏下盾螨同类相食的倾向。将成年螨和若螨作为捕食者，引入同种的卵、幼虫、若螨、成年雌螨或雄螨作为猎物，并记录被杀死个体的数量。此外，对同种猎物上的产卵率进行了量化，并计算其与消耗猎物数量的相关性，以评估同类相食对产卵的影响。结果表明，在两种下盾螨中，同类相食现象很少发生，唯一的例外是尖狭下盾螨若螨，它们每天会吃掉一个同种卵。此外，在有替代猎物的情况下，从未发生过同类相食现象。在实验过程中，两种螨类的产卵率均有所下降，但仅尖狭下盾螨的产卵率与同类相食率呈正相关。本文还讨论了同类相食对尖狭下盾螨和迈氏下盾螨种群的益处。
