Feeding Preferences of Two Predatory Snails Introduced to Hawaii and Their Conservation Implications
Feeding Preferences of Two Predatory Snails Introduced to Hawaii and Their Conservation Implications
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引入夏威夷的两种掠食性蜗牛的摄食偏好及其保护意义
DOI：
10.4002/040.053.0106
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发表时间：
2010
影响因子：
11.1
通讯作者：
R. Cowie
中科院分区：
文献类型：
--
作者：
W. M. Meyer;R. Cowie
两种引进的掠食性陆生蜗牛，玫瑰裸腹蜗牛和尖唇蜗牛，与夏威夷和太平洋岛屿原生陆生蜗牛的减少有关。研究了E. rosea和O.在这方面，我们首先关注的是猎物的大小和对物种的偏好，其次是消费率的量化，这对于解决对自然种群可能产生的影响程度是必要的。在猎物大小偏好实验中，E. rosea总是消耗更多的蜗牛在较小的大小类。在捕食选择实验中，E. rosea喜欢蜗牛而不是蛞蝓，但在蜗牛物种之间没有偏好。大小偏好实验表明，O.鳄鱼只吃壳长小于3毫米的猎物。在捕食性实验中，O. Alliarius吃掉了所有提供的蜗牛物种，但没有吃掉任何一种鼻涕虫物种。消耗率与捕食者的大小正相关，较大的捕食者E。rosea的消耗率远高于O. alliarius和较大的E. rosea比E.玫瑰色。这些结果具有不幸的保护后果，因为它们表明E。rosea和O.尽管它们很少吃蛞蝓，但它们是捕食蜗牛的多面手，优先捕食最小的蜗牛。由于许多现存的夏威夷和太平洋岛屿蜗牛物种很小，它们有被这两种引入的捕食者捕食的风险，而入侵的鼻涕虫--夏威夷没有本土鼻涕虫--可能不会受到它们的影响。
ABSTRACT Two introduced predatory land snails, Euglandina rosea and Oxychilus alliarius, have been implicated in the decline of native Hawaiian and Pacific island land snails. We examined the feeding ecology of E. rosea and O. alliarius, focusing first on prey size and species preferences, and second on quantifying consumption rates, which is necessary to address the possible levels of impact on natural populations. In prey-size preference experiments, E. rosea always consumed more snails in the smaller size class. In prey-species preference experiments, E. rosea preferred snails to slugs but showed no preference among snail species. Size preference experiments indicated that O. alliarius will only consume prey less than 3 mm in shell length. In prey species preference experiments O. alliarius consumed every snail species offered but did not consume either of the slug species. Consumption rates were positively related to the size of the predator, with the larger predator, E. rosea, having a much higher consumption rate than O. alliarius, and with larger E. rosea consuming more than smaller E. rosea. These results have unfortunate conservation ramifications, because since they indicate that both E. rosea and O. alliarius are generalist snail predators feeding preferentially on the smallest snails, although they rarely eat slugs. Since many extant Hawaiian and Pacific island snail species are small, they are at risk of predation by these two introduced predators, while invasive slugs — there are no native slugs in Hawaii — may not be impacted by them.