Predation and prey size choice by the carabid beetle Pterostichus melanarius (Coleoptera: Carabidae):: the dangers of extrapolating from laboratory to field
Predation and prey size choice by the carabid beetle Pterostichus melanarius (Coleoptera: Carabidae):: the dangers of extrapolating from laboratory to field
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DOI：
10.1079/ber2003240
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发表时间：
2003-05-01
影响因子：
1.9
通讯作者：
Glen, DM
中科院分区：
文献类型：
--
作者：
McKemey, AR;Symondson, WOC;Glen, DM
在半野外条件下，研究了通才步甲Pterostichus melanarius（Illiger）捕食对田间蛞蝓Deroceras reticulatum（Muller）种群的影响，以及猎物大小对捕食者-猎物相互作用的影响。据推测，环境的异质性将导致非常不同的模式，比较死亡率比可能推导出的大小选择实验室进行。模拟麦田条件的室外小地块的结果表明，黑腹拟杆菌显著减少了所有大小类别的蛞蝓数量，没有明显的偏好。这与早期实验室研究的结果形成鲜明对比，在早期实验室研究中，这种甲虫优先吃最小的鼻涕虫。小地块中的蛞蝓大小范围为2-100 mg，小地块中的数量反映了田间的大小频率分布。甲虫在小地块含有高密度的蛞蝓的重量显着增加，相反，甲虫在小地块与低蛞蝓密度或没有添加蛞蝓，这并没有。利用抗蛞蝓单克隆抗体进行的酶联免疫吸附测定（ELISA）表明，在蛞蝓密度较高的地方，甲虫的肠道中有更多的蛞蝓蛋白。得出的结论是，环境异质性可能提供了更大的避难所的数量和多样性比较大的蛞蝓，抵消实验室测量的大小偏好在竞技场没有避难所。这些结果对一系列涉及种间和种内猎物大小选择的生态学研究具有影响，并强调了从实验室外推到实地的危险。
The impact of predation by the generalist carabid beetle Pterostichus melanarius (Illiger) on populations of the field slug Deroceras reticulatum (MUller), and the effects of prey size on the predator-prey interaction, were measured under semi-field conditions. It was hypothesized that environmental heterogeneity would lead to very different patterns of comparative mortality than might be deduced from size choice experiments conducted in the laboratory. Results from outdoor mini-plots, emulating conditions in a field of wheat, demonstrated that P. melanarius significantly reduced numbers of slugs from all size classes, with no apparent preferences. This was in marked contrast to results from earlier laboratory studies, where this beetle fed preferentially on the smallest slugs. The slugs in the mini-plots ranged in size from 2-100 mg and the numbers in the mini-plot reflected the size frequency distribution in the field. Beetles in mini-plots containing high densities of slugs increased significantly in weight, in contrast to beetles in mini-plots with low slug density or no added slugs, which did not. Enzyme-linked immunosorbent assays (ELISA), using anti-slug monoclonal antibodies, showed that where there was a higher density of slugs there was more slug protein in the guts of the beetles. It was concluded that environmental heterogeneity probably provided a greater number and diversity of refugia for smaller than for larger slugs, counteracting laboratory-measured size preferences measured in arenas without refugia. These results have implications for a range of ecological studies involving inter- and intra-specific prey size choice, and emphasize the dangers of extrapolating from the laboratory to the field.