Proximate causes of cannibalistic polyphenism in larval tiger salamanders
Proximate causes of cannibalistic polyphenism in larval tiger salamanders
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DOI：
10.2307/177041
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发表时间：
1999-04-01
期刊：
影响因子：
4.8
通讯作者：
Pfennig, DW
中科院分区：
文献类型：
--
作者：
Hoffman, EA;Pfennig, DW
虎蝾螈幼体，Ambystoma tigrinum，以小头“典型”变体形式存在，主要以水生无脊椎动物为食，而大头“食人”变体则经常捕食同种动物。先前的实验表明，当同种幼虫拥挤时，食人动物会被兼性诱导。我们问：（1）什么感官线索触发食人者的表达？ (2) 幼虫年龄是否影响食人动物的表达？ (3) 同类相食也会因异种动物拥挤而诱发吗？ (4) 食人者会抑制他人成为食人者吗？我们发现其他蝾螈幼虫的触觉提示对于引诱同类相食是必要的。当虎蝾螈幼虫与同类幼虫挤在一起时，就会产生食人动物，并且这些异种诱导的食人动物的表达年龄比同种动物诱导的幼虫更早。此外，较年轻的幼虫更有可能发育成食人者。最后，食人者发出的视觉和化学信号并没有抑制其他幼虫发育成食人者。我们推断多型现象在该物种和其他物种中的适应性意义。
Larval tiger salamanders, Ambystoma tigrinum, exist as small-headed "typical" morphs that feed mainly on aquatic invertebrates and as large-headed "cannibal" morphs that often prey on conspecifics. Previous experiments have demonstrated that cannibals are induced facultatively when crowded with conspecific larvae. We asked: (1)What sensory cues trigger expression of cannibals? (2) Does larval age influence expression of cannibals? (3) Are cannibals also induced by crowding with heterospecifics? (4) Do cannibals suppress others from developing into cannibals? We found that tactile cues from other salamander larvae were necessary to elicit cannibals. Cannibals were produced when tiger salamander larvae were crowded with congeneric larvae, and these heterospecific-induced cannibals were expressed at an earlier age than those induced by conspecifics. Furthermore, younger larvae were more likely to develop into cannibals. Finally, visual and chemical cues from cannibals did not suppress other larvae from developing into cannibals. We infer the adaptive significance of polyphenism in this and other species.