Hoso Masaki
Hakubi Center for Advanced Research, Kyoto University, Kyoto, Japan; Department of Zoology/Graduate School of Science, Kyoto University, Kyoto, Japan.
PeerJ. 2017 Mar 2;5:e3011. doi: 10.7717/peerj.3011. eCollection 2017.
In vertebrates, the left-and-right pairs of homologous organs are generally present in equal numbers. A remarkable exception is snail-eating snakes in the family Pareidae: almost all the pareid snakes have much more teeth on the right mandible than on the left for functional specialization in feeding on the dextral majority of land snails. Because the only exceptional species with symmetric dentition has been regarded as a slug-eater, the extent of dietary specialization on slugs could shape the degree of the lateral asymmetry of mandibular dentition (dentition asymmetry) even among snail eaters.
To test this, I compared the morphology and behavior of two sympatric species of Taiwanese snail-eating snakes, and .
Specimens collected in the same locality showed that the dentition asymmetry of was significantly smaller than that of . Congruent to its weak asymmetry, showed a strong preference of slugs to snails in the feeding experiment.
The dietary specialization of on slugs would contribute to niche partitioning from the sympatric congener . This study suggests that the diverse variation in the dentition asymmetry of pareid snakes is the result of their dietary specialization and divergence.
在脊椎动物中，左右成对的同源器官数量通常相等。一个显著的例外是食蜗蛇科的食蜗蛇：几乎所有食蜗蛇右下颌的牙齿都比左下颌多，这有利于其以大多数右旋的陆地蜗牛为食时进行功能特化。由于唯一具有对称齿列的例外物种被认为是以蛞蝓为食，因此即使在食蜗蛇中，对蛞蝓的食性特化程度也可能影响下颌齿列的侧向不对称程度（齿列不对称）。
为了验证这一点，我比较了两种同域分布的台湾食蜗蛇物种——[物种名1]和[物种名2]的形态和行为。
在同一地点采集的标本显示，[物种名1]的齿列不对称程度明显小于[物种名2]。与其较弱的不对称性相一致，[物种名1]在进食实验中表现出对蛞蝓的强烈偏好，而不是蜗牛。
[物种名1]对蛞蝓的食性特化有助于其与同域分布的同类物种[物种名2]进行生态位划分。这项研究表明，食蜗蛇科蛇类齿列不对称的多样变化是其食性特化和分化的结果。
