Griffiths Georgianne J K, Alexander Colin J, Holland John M, Kennedy Peter J, Perry Joe N, Symondson William O C, Winder Linton
Biological Sciences, University of Plymouth at Seale-Hayne, Newton Abbot, Devon TQ12 6NQ, UK.
Mol Ecol. 2008 Apr;17(7):1828-39. doi: 10.1111/j.1365-294X.2007.03682.x. Epub 2008 Feb 14.
Spatially explicit predator-prey interactions can alter the predatory potential of natural enemies augmented through conservation biological control. To test hypotheses regarding such interactions and predatory efficiency, we used a combination of molecular techniques and mark-release-recapture to study the foraging behaviour of a generalist carabid predator, Poecilus cupreus, in response to spatial patterns of its cereal aphid prey (Metapolophium dirhodum and Sitobion avenae). Beetle and aphid numbers were measured across two grids of sampling locations, within which aphid spatial pattern had been manipulated to generate patchy and more homogenous distributions. Aphid consumption was measured by enzyme-linked immunosorbent assays (ELISA) of beetle gut contents, using an aphid-specific monoclonal antibody. Movement and distribution patterns suggest that P. cupreus does not aggregate at, nor instigate prey-taxis within, aphid patches. However, more than two-thirds of the 2169 P. cupreus tested by ELISA had consumed aphids and the proportion of beetles containing aphid proteins was positively related to aphid density. Against expectation, the proportion of predators feeding on aphids was greatest where prey were homogenously distributed, and this was attributed to the loss of partial refuges for prey in aphid patches. The functional value of this type of uniform foraging strategy is ideally suited to early colonization of the crop habitat, when aphid numbers are low, before populations build up and form strong spatial patterns.
空间明确的捕食者 - 猎物相互作用可以改变通过保护生物防治增加的天敌的捕食潜力。为了检验关于此类相互作用和捕食效率的假设，我们结合分子技术和标记重捕法，研究了一种多食性步甲捕食者铜绿婪步甲（Poecilus cupreus）对其谷物蚜虫猎物（麦二叉蚜Metapolophium dirhodum和麦长管蚜Sitobion avenae）空间格局的觅食行为。在两个采样位置网格中测量了甲虫和蚜虫的数量，其中蚜虫的空间格局已被操纵以产生斑块状和更均匀的分布。使用蚜虫特异性单克隆抗体，通过对甲虫肠道内容物的酶联免疫吸附测定（ELISA）来测量蚜虫的消耗量。移动和分布模式表明，铜绿婪步甲不会在蚜虫斑块处聚集，也不会在其中引发猎物定向行为。然而，通过ELISA检测的2169只铜绿婪步甲中，超过三分之二的个体取食了蚜虫，并且含有蚜虫蛋白质的甲虫比例与蚜虫密度呈正相关。与预期相反，在猎物均匀分布的地方，以蚜虫为食的捕食者比例最大，这归因于蚜虫斑块中猎物部分避难所的丧失。这种均匀觅食策略的功能价值非常适合在作物生境早期定殖时，即蚜虫数量较低、种群尚未建立并形成强烈空间格局之前的情况。
