Department of Animal Ecology, Justus Liebig University, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany,
Oecologia. 2013 Oct;173(2):579-89. doi: 10.1007/s00442-013-2634-7. Epub 2013 Mar 14.
Agricultural management and vegetation complexity affect arthropod diversity and may alter trophic interactions between predators and their prey. Web-building spiders are abundant generalist predators and important natural enemies of pests. We analyzed how management intensity (tillage, cutting of the vegetation, grazing by cattle, and synthetic and organic inputs) and vegetation complexity (plant species richness, vegetation height, coverage, and density) affect rarefied richness and composition of web-building spiders and their prey with respect to prey availability and aphid predation in 12 habitats, ranging from an uncut fallow to a conventionally managed maize field. Spiders and prey from webs were collected manually and the potential prey were quantified using sticky traps. The species richness of web-building spiders and the order richness of prey increased with plant diversity and vegetation coverage. Prey order richness was lower at tilled compared to no-till sites. Hemipterans (primarily aphids) were overrepresented, while dipterans, hymenopterans, and thysanopterans were underrepresented in webs compared to sticky traps. The per spider capture efficiency for aphids was higher at tilled than at no-till sites and decreased with vegetation complexity. After accounting for local densities, 1.8 times more aphids were captured at uncut compared to cut sites. Our results emphasize the functional role of web-building spiders in aphid predation, but suggest negative effects of cutting or harvesting. We conclude that reduced management intensity and increased vegetation complexity help to conserve local invertebrate diversity, and that web-building spiders at sites under low management intensity (e.g., semi-natural habitats) contribute to aphid suppression at the landscape scale.
农业管理和植被复杂性会影响节肢动物多样性，并可能改变捕食者与其猎物之间的营养关系。织网蜘蛛是丰富的全能捕食者，也是害虫的重要天敌。我们分析了管理强度（耕作、植被切割、牛放牧以及合成和有机投入）和植被复杂性（植物物种丰富度、植被高度、覆盖率和密度）如何影响稀疏化的织网蜘蛛及其猎物的丰富度和组成，以及猎物的可用性和蚜虫捕食，涉及 12 种生境，从未切割的休耕地到常规管理的玉米地。通过手动收集蜘蛛网中的蜘蛛和猎物，并使用粘性陷阱量化潜在猎物。织网蜘蛛的物种丰富度和猎物的目丰富度随着植物多样性和植被覆盖率的增加而增加。与免耕相比，耕作的地方猎物目丰富度较低。半翅目（主要是蚜虫）在网中过度代表，而双翅目、膜翅目和缨翅目在网中相对于粘性陷阱中代表不足。与免耕相比，在耕作的地方，每只蜘蛛对蚜虫的捕获效率更高，而随着植被复杂性的增加，捕获效率降低。在考虑了局部密度后，未切割的地方比切割的地方捕获的蚜虫多 1.8 倍。我们的结果强调了织网蜘蛛在蚜虫捕食中的功能作用，但表明切割或收获会产生负面影响。我们得出的结论是，降低管理强度和增加植被复杂性有助于保护本地无脊椎动物多样性，而管理强度较低（例如，半自然生境）的地方的织网蜘蛛有助于在景观尺度上抑制蚜虫。
