Bible Jillian M, Griffith Kaylee R, Sanford Eric
Bodega Marine Laboratory, University of California, 2099 Westshore Road, Bodega Bay, CA, 94923, USA.
Department of Evolution and Ecology, University of California, One Shields Ave, Davis, CA, 95616, USA.
Oecologia. 2017 Mar;183(3):809-819. doi: 10.1007/s00442-017-3811-x. Epub 2017 Jan 13.
The prey naiveté hypothesis suggests that native prey may be vulnerable to introduced predators because they have not evolved appropriate defenses. However, recent evidence suggests that native prey sometimes exhibit induced defenses to introduced predators, as a result of rapid evolution or other processes. We examined whether Olympia oysters (Ostrea lurida) display inducible defenses in the presence of an invasive predator, the Atlantic oyster drill (Urosalpinx cinerea), and whether these responses vary among oyster populations from estuaries with and without this predator. We spawned oysters from six populations distributed among three estuaries in northern California, USA, and raised their offspring through two generations under common conditions to minimize effects of environmental history. We exposed second-generation oysters to cue treatments: drills eating oysters, drills eating barnacles, or control seawater. Oysters from all populations grew smaller shells when exposed to drill cues, and grew thicker and harder shells when those drills were eating oysters. Oysters exposed to drills eating other oysters were subsequently preyed upon at a slower rate. Although all oyster populations exhibited inducible defenses, oysters from the estuary with the greatest exposure to drills grew the smallest shells suggesting that oyster populations have evolved adaptive differences in the strength of their responses to predators. Our findings add to a growing body of literature that suggests that marine prey may be less likely to exhibit naiveté in the face of invasive predators than prey in communities that are more isolated from native predators, such as many freshwater and terrestrial island ecosystems.
猎物幼稚假说认为，本地猎物可能易受外来捕食者的攻击，因为它们尚未进化出适当的防御机制。然而，最近的证据表明，由于快速进化或其他过程，本地猎物有时会对引入的捕食者表现出诱导防御。我们研究了奥林匹亚牡蛎（Ostrea lurida）在入侵性捕食者——大西洋牡蛎钻孔螺（Urosalpinx cinerea）存在时是否会表现出诱导防御，以及这些反应在有和没有这种捕食者的河口的牡蛎种群中是否存在差异。我们从分布在美国加利福尼亚州北部三个河口的六个种群中采集牡蛎进行产卵，并在共同条件下将它们的后代饲养两代，以尽量减少环境历史的影响。我们将第二代牡蛎暴露于不同的提示处理下：钻孔螺吃牡蛎、钻孔螺吃藤壶或对照海水。当暴露于钻孔螺的提示时，所有种群的牡蛎壳生长得更小，而当钻孔螺吃牡蛎时，它们的壳变得更厚更硬。暴露于钻孔螺吃其他牡蛎的提示下的牡蛎随后被捕食的速度较慢。尽管所有牡蛎种群都表现出诱导防御，但来自与钻孔螺接触最多的河口的牡蛎壳生长得最小，这表明牡蛎种群在对捕食者反应的强度上已经进化出适应性差异。我们的研究结果增加了越来越多的文献证据，表明与许多淡水和陆地岛屿生态系统等与本地捕食者隔离程度更高的群落中的猎物相比，海洋猎物面对入侵捕食者时表现出幼稚的可能性较小。
