科学家发现了一些化学物质，它们能表明一只蚂蚁还活着、并阻止它的同事把它丢到蚁群的墓地。此前的研究认为，蚂蚁把死去的同事从蚁群中移除是因为蚂蚁尸体中降解产物的积累。然而，Dong-Hwan Choe及其同事认为，蚂蚁处置组在一只蚂蚁死后1小时内就采取了行动，这远远早于降解的化学产物能够散发出来的时间。
这组科学家发现，移除死蚂蚁的化学信号总是存在，但是被其他化学物质抑制，而这些化学物质在蚂蚁死后很快就消失。这组科学家使用溶剂萃取了存在于刚刚被杀死或死去1个小时的工蚁表皮中的这些化学物质。当涂抹了这些萃取物的蚂蚁蛹被放在外面的时候——工蚁通常会回收蛹并把它们送回蚁巢中——只有那些涂抹了来自刚刚被杀死的蚂蚁的萃取物的蛹被忽略了，没有被搬走。而其他的蛹被扔进了蚁群的垃圾堆。色谱和质谱分析表明了dolichodial和iridomyrmecin这两种化合物的存在。活的工蚁在表皮中分泌这些化合物。但是这组作者发现，如果不持续更新，在40分钟内dolichodial和iridomyrmecin或者将挥发，或者将变得失去活性。（生物谷Bioon.com）
生物谷推荐原始出处：
PNAS May 4, 2009, doi: 10.1073/pnas.0901270106
Chemical signals associated with life inhibit necrophoresis in Argentine ants
Dong-Hwan Choe,1, Jocelyn G. Millar and Michael K. Rust
One of the most conspicuous and stereotyped activities of social insects such as ants and honey bees is necrophoresis, the removal of dead colony members from the nest. Previous researchers suggested that decomposition products such as fatty acids trigger necrophoric behavior by ant workers. However, fatty acids elicit both foraging and necrophoric responses, depending on the current nest activities (e.g., feeding or nest maintenance). Furthermore, workers often carry even freshly killed workers (dead for <1 h) to refuse piles before significant decomposition has a chance to occur. Here, we show that the cuticular chemistry of Argentine ant workers, Linepithema humile, undergoes rapid changes after death. When the workers are alive or freshly killed, relatively large amounts of 2 characteristic ant-produced compounds, dolichodial and iridomyrmecin, are present on the ants' cuticle. However, these compounds disappear from the cuticle within about 1 h after death. We demonstrate how this phenomenon supports an alternative mechanism of ant necrophoresis in which the precise recognition and rapid removal of dead nestmates are elicited by the disappearance of these chemical signals associated with life.
