Department of Zoology, Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Budapest, Nagykovácsi út 26-30, H-1029, Hungary.
Department of Entomology, University of Kentucky, S-225 Ag Science Center N Lexington, Kentucky, 40506-0091, USA.
Sci Rep. 2017 Aug 4;7(1):7266. doi: 10.1038/s41598-017-07509-w.
Predators can limit prey abundance and/or levels of activity. The magnitudes of these effects are contingent on predator and prey traits that may change with environmental conditions. Aberrant thermal regimes could disrupt pest suppression through asymmetric effects, e.g. heat-sensitive predator vs. heat-tolerant prey. To explore potential effects of warming on suppressing pests and controlling herbivory in a vegetable crop, we performed laboratory experiments exposing an important pest species to two spider predator species at different temperatures. Heat tolerance was characterised by the critical thermal maxima parameter (CTM50) of the cucumber beetle (Diabrotica undecimpunctata), wolf spider (Tigrosa helluo), and nursery web spider (Pisaurina mira). Cucumber beetles and wolf spiders were equally heat tolerant (CTM50 > 40 °C), but nursery web spiders had limited heat tolerance (CTM50 = 34 °C). Inside mesocosms, beetle feeding increased with temperature, wolf spiders were always effective predators, nursery web spiders were less lethal at high temperature (38 °C). Neither spider species reduced herbivory at ambient temperature (22 °C), however, at warm temperature both species reduced herbivory with evidence of a dominant non-consumptive effect. Our experiments highlight the contingent nature of predator-prey interactions and suggest that non-consumptive effects should not be ignored when assessing the impact of temperature change.
捕食者可以限制猎物的丰度和/或活动水平。这些影响的程度取决于捕食者和猎物的特征，这些特征可能会随着环境条件的变化而改变。异常的热环境可能会通过不对称的影响（例如，对热敏感的捕食者与耐热的猎物）破坏害虫的抑制作用。为了探索变暖对抑制蔬菜作物害虫和控制食草作用的潜在影响，我们在不同温度下对两种蜘蛛捕食者暴露于一种重要的害虫物种进行了实验室实验。黄瓜甲虫（Diabrotica undecimpunctata）、狼蛛（Tigrosa helluo）和苗圃网蛛（Pisaurina mira）的临界热最大值参数（CTM50）用于确定热耐受性。黄瓜甲虫和狼蛛的耐热性相同（CTM50>40°C），但苗圃网蛛的耐热性有限（CTM50=34°C）。在中观模型中，随着温度的升高，甲虫的取食增加，狼蛛始终是有效的捕食者，而在高温（38°C）下，苗圃网蛛的致死率较低。两种蜘蛛在环境温度（22°C）下均未降低食草作用，但在温暖温度下，两种蜘蛛都通过明显的非消耗性效应降低了食草作用。我们的实验强调了捕食者-猎物相互作用的偶然性，并表明在评估温度变化的影响时，不应忽视非消耗性效应。
