Biology Department, Western Washington University, Bellingham, WA 98225, USA.
Oecologia. 2012 May;169(1):105-15. doi: 10.1007/s00442-011-2188-5. Epub 2011 Nov 15.
Inducible defenses have the potential to affect both invasion success and the structure of invaded communities. However, little is known about the cues used for risk-recognition that influence the expression of inducible defenses in invasive prey, because they involve a novel threat. In laboratory experiments, we investigated behavioral defenses induced by a native crab on two invasive oyster drills (marine whelks Urosalpinx cinerea and Ocinebrina inornata). Both drills hid more often and reduced their feeding rates when they detected predators consuming conspecific prey. Examination of the responses of U. cinerea to specific cue sources (predator kairomones, conspecific alarm cues) indicated that this species had the strongest responses to cues from injured conspecifics, but that it did recognize the novel crab predator. Our observation of native predator (per se) recognition by an invasive marine prey is novel. In addition, we observed that neither species of drill reduced their defensive behavior to reflect predation risk shared by a group of prey. The lack of density dependence in risk-assessment could cause populations of invasive prey to transmit both quantitatively and qualitatively different community effects over the course of an invasion as abundance changes. Together, these findings demonstrate several ways that the risk-assessment strategies could be important in establishment and post-establishment dynamics of invasive prey.
诱导防御有可能影响入侵的成功和入侵群落的结构。然而，对于影响入侵猎物诱导防御表达的风险识别线索知之甚少，因为这涉及到一种新的威胁。在实验室实验中，我们研究了一种本地蟹对两种入侵牡蛎钻螺（海洋海蜗牛 Urosalpinx cinerea 和 Ocinebrina inornata）的行为防御。当两种钻螺检测到捕食者食用同种猎物时，它们躲藏的次数更多，进食速度也降低。对 U. cinerea 对特定线索来源（捕食者信息素、同种警报线索）的反应的检查表明，该物种对同种受伤个体的线索反应最强，但它确实识别了新的蟹类捕食者。我们观察到一种入侵海洋猎物对本地捕食者（本身）的识别是新颖的。此外，我们观察到，这两种钻螺都没有减少它们的防御行为，以反映一群猎物共同面临的捕食风险。在入侵过程中，由于数量的变化，风险评估中缺乏密度依赖性可能导致入侵猎物种群传递数量和质量不同的群落效应。这些发现共同表明，风险评估策略在入侵猎物的建立和建立后动态中可能具有重要意义。
