Fernández Ferrari M Celeste, Schausberger Peter
Group of Arthropod Ecology and Behavior, Division of Plant Protection, Department of Crop Sciences, University of Natural Resources and Life Sciences, Peter Jordanstrasse 82, 1190, Vienna, Austria.
Naturwissenschaften. 2013 Jun;100(6):541-9. doi: 10.1007/s00114-013-1050-5. Epub 2013 May 4.
Prey perceiving predation risk commonly change their behavior to avoid predation. However, antipredator strategies are costly. Therefore, according to the threat-sensitive predator avoidance hypothesis, prey should match the intensity of their antipredator behaviors to the degree of threat, which may depend on the predator species and the spatial context. We assessed threat sensitivity of the two-spotted spider mite, Tetranychus urticae, to the cues of three predatory mites, Phytoseiulus persimilis, Neoseiulus californicus, and Amblyseius andersoni, posing different degrees of risk in two spatial contexts. We first conducted a no-choice test measuring oviposition and activity of T. urticae exposed to chemical traces of predators or traces plus predator eggs. Then, we tested the site preference of T. urticae in choice tests, using artificial cages and leaves. In the no-choice test, T. urticae deposited their first egg later in the presence of cues of P. persimilis than of the other two predators and cue absence, indicating interspecific threat-sensitivity. T. urticae laid also fewer eggs in the presence of cues of P. persimilis and A. andersoni than of N. californicus and cue absence. In the artificial cage test, the spider mites preferred the site with predator traces, whereas in the leaf test, they preferentially resided on leaves without traces. We argue that in a nonplant environment, chemical predator traces do not indicate a risk for T. urticae, and instead, these traces function as indirect habitat cues. The spider mites were attracted to these cues because they associated them with the existence of a nearby host plant.
感知到捕食风险的猎物通常会改变其行为以避免被捕食。然而，反捕食策略是有代价的。因此，根据威胁敏感的捕食者回避假说，猎物应使其反捕食行为的强度与威胁程度相匹配，而威胁程度可能取决于捕食者种类和空间背景。我们评估了二斑叶螨（Tetranychus urticae）对三种捕食螨——智利小植绥螨（Phytoseiulus persimilis）、加州新小绥螨（Neoseiulus californicus）和安德森钝绥螨（Amblyseius andersoni）——在两种空间背景下构成不同程度风险的线索的威胁敏感性。我们首先进行了一项无选择测试，测量暴露于捕食者化学痕迹或痕迹加捕食者卵的二斑叶螨的产卵和活动情况。然后，我们使用人工笼子和叶片在选择测试中测试了二斑叶螨的位点偏好。在无选择测试中，与其他两种捕食者的线索以及无线索情况相比，二斑叶螨在有智利小植绥螨线索时产卵更晚，这表明存在种间威胁敏感性。与有加州新小绥螨线索和无线索情况相比，二斑叶螨在有智利小植绥螨和安德森钝绥螨线索时产卵也更少。在人工笼子测试中，叶螨更喜欢有捕食者痕迹的位点，而在叶片测试中，它们优先栖息在没有痕迹的叶片上。我们认为，在非植物环境中，化学捕食者痕迹对二斑叶螨并不意味着风险，相反，这些痕迹起到间接栖息地线索的作用。叶螨被这些线索所吸引，因为它们将其与附近宿主植物的存在联系起来。
