Losey John E, Denno Robert F
Department of Entomology, University of Maryland, College Park, MD 20742, USA, , , , , , US.
Oecologia. 1998 Jun;115(1-2):245-252. doi: 10.1007/s004420050513.
A series of laboratory experiments was conducted to determine the effect of interspecific differences on prey defensive behavior on the susceptibility of two aphid species (Acyrthosiphon pisum and A. kondoi) to a ground-foraging predator, Harpalus pennsylvanicus, and a foliar-foraging predator, Coccinella septempunctata. These organisms are representative of a biologically and economically important predator/prey system in alfalfa. The primary defensive behavior of both aphid species toward C. septempunctata was to "drop" from the plant. Both aphid species were significantly more likely to drop from the plant in the presence of C. septempunctata. However, when C. septempunctata was present, a significantly lower proportion of A. kondoi individuals dropped (0.42 ± 0.07) compared to A. pisum (0.73 ± 0.08). As a result of their lower propensity to drop from the plant A. kondoi individuals are significantly more likely to be consumed by C. septempunctata. Conversely, the higher propensity of A. pisum individuals to drop increased their susceptibility to ground-foraging predators. When A. pisum was the prey species, ground-foraging predators made a significant contribution to overall aphid suppression and there was a significant synergistic interaction between ground and foliar-foraging predators. When A. kondoi was the prey there was no interaction between the predator species. As either a cause or consequence of its higher propensity to drop, A. pisum seems to be more adapted for survival and dispersal off the plant. In comparison to A. kondoi individuals, A. pisum individuals relocate plants more quickly (63 ± 41 s vs. 164 ± 39 s), disperse farther (18 ± 1.7 cm vs. 13 ± 0.66 cm), and survive longer (37 ± 2.0 h vs. 25 ± 2.0) off the plant. This study demonstrates the importance of prey defensive behavior in determining the susceptibility of a prey species to a multiple-predator complex.
进行了一系列实验室实验，以确定种间差异对猎物防御行为的影响，以及两种蚜虫（豌豆蚜和苜蓿蚜）对地面觅食捕食者宾夕法尼亚步甲和叶面觅食捕食者七星瓢虫的易感性。这些生物代表了苜蓿中一个具有生物学和经济重要性的捕食者/猎物系统。两种蚜虫对七星瓢虫的主要防御行为是从植物上“掉落”。在有七星瓢虫存在的情况下，两种蚜虫从植物上掉落的可能性都显著更高。然而，当有七星瓢虫存在时，苜蓿蚜个体掉落的比例（0.42±0.07）显著低于豌豆蚜（0.73±0.08）。由于苜蓿蚜个体从植物上掉落的倾向较低，它们被七星瓢虫捕食的可能性显著更高。相反，豌豆蚜个体较高的掉落倾向增加了它们对地面觅食捕食者的易感性。当豌豆蚜作为猎物物种时，地面觅食捕食者对总体蚜虫抑制有显著贡献，并且地面和叶面觅食捕食者之间存在显著的协同相互作用。当苜蓿蚜作为猎物时，捕食者物种之间没有相互作用。作为其较高掉落倾向的原因或结果，豌豆蚜似乎更适应在植物外生存和扩散。与苜蓿蚜个体相比，豌豆蚜个体重新找到植物的速度更快（63±41秒对164±39秒），扩散得更远（18±1.7厘米对13±0.66厘米），并且在植物外存活的时间更长（37±2.0小时对25±2.0小时）。这项研究证明了猎物防御行为在确定猎物物种对多种捕食者复合体的易感性方面的重要性。
