Laboratoire d'Ethologie Expérimentale et Comparée EA 4443, Université Paris Nord, Villetaneuse, France.
PLoS One. 2009 Aug 12;4(8):e6573. doi: 10.1371/journal.pone.0006573.
Although helping behavior is ubiquitous throughout the animal kingdom, actual rescue activity is particularly rare. Nonetheless, here we report the first experimental evidence that ants, Cataglyphis cursor, use precisely directed rescue behavior to free entrapped victims; equally important, they carefully discriminate between individuals in distress, offering aid only to nestmates. Our experiments simulate a natural situation, which we often observed in the field when collecting Catagyphis ants, causing sand to collapse in the process. Using a novel experimental technique that binds victims experimentally, we observed the behavior of separate, randomly chosen groups of 5 C. cursor nestmates under one of six conditions. In five of these conditions, a test stimulus (the "victim") was ensnared with nylon thread and held partially beneath the sand. The test stimulus was either (1) an individual from the same colony; (2) an individual from a different colony of C cursor; (3) an ant from a different ant species; (4) a common prey item; or, (5) a motionless (chilled) nestmate. In the final condition, the test stimulus (6) consisted of the empty snare apparatus. Our results demonstrate that ants are able to recognize what, exactly, holds their relative in place and direct their behavior to that object, the snare, in particular. They begin by excavating sand, which exposes the nylon snare, transporting sand away from it, and then biting at the snare itself. Snare biting, a behavior never before reported in the literature, demonstrates that rescue behavior is far more sophisticated, exact and complexly organized than the simple forms of helping behavior already known, namely limb pulling and sand digging. That is, limb pulling and sand digging could be released directly by a chemical call for help and thus result from a very simple mechanism. However, it's difficult to see how this same releasing mechanism could guide rescuers to the precise location of the nylon thread, and enable them to target their bites to the thread itself.
虽然帮助行为在动物界中普遍存在，但实际的救援活动却特别罕见。尽管如此，我们在此报告了第一个实验证据，表明蚂蚁 Cataglyphis cursor 确实会使用定向救援行为来解救被困的受害者；同样重要的是，它们会仔细区分处于困境中的个体，只向巢伴提供帮助。我们的实验模拟了一种自然情况，在野外收集 Catagyphis 蚂蚁时，我们经常会观察到这种情况，导致沙子在这个过程中坍塌。使用一种新颖的实验技术，我们将实验中受困的受害者用尼龙线固定，观察到 5 只随机选择的 Cataglyphis cursor 个体在六种情况下的行为。在这六种情况中的五种中，测试刺激物（“受害者”）被尼龙线缠住，并部分埋在沙子下面。测试刺激物要么是（1）来自同一蚁群的个体；要么是（2）来自不同 Cataglyphis cursor 蚁群的个体；要么是（3）来自不同蚂蚁物种的个体；要么是（4）常见的猎物；或者，（5）一个静止不动（被冻僵）的巢伴。在最后一种情况下，测试刺激物（6）是由空的捕蝇器组成的。我们的结果表明，蚂蚁能够准确识别出困住它们相对个体的是什么，并将其行为指向该物体，特别是捕蝇器。它们首先挖掘沙子，暴露尼龙捕蝇器，将沙子从它身上运走，然后咬捕蝇器本身。咬捕蝇器，一种以前在文献中从未报道过的行为，表明救援行为比已知的简单帮助行为，即肢体拉动和挖沙，要复杂得多。也就是说，肢体拉动和挖沙可能直接通过求助的化学信号释放，因此可能源于一个非常简单的机制。然而，很难想象这种相同的释放机制如何引导救援者找到尼龙线的确切位置，并使它们能够将叮咬目标对准线本身。
