| Behavioural effects of juvenile hormone and their influence on division of labour in leaf-cutting ant societies |
Norman VC , Hughes WO |
图片来源：Martin Castorena
把一团果冻扔在厨房台面上，你可能很快会看见一群蚂蚁径直朝这些食物奔来。它们遵循的是由最先发现食物的蚁群同伴所留下的被称为信息素的化学线索。通过遵循信息素，蚂蚁能反复享用果冻美食。不过，一项最新研究显示，信息素并非故事的全部：蚂蚁对路径的单独记忆也会鼓励这些重复的到访。
在被捕获的黑色花园蚂蚁（如图所示）发现并享用淡糖水时，研究人员观察了它们的行为。随后，他们将蚂蚁移走，擦掉信息素轨迹，并加入另一种更甜的食物源。当研究人员让蚂蚁返回围栏中时，这些昆虫仍选择了最初的糖水，尽管引导它们的此前信息素轨迹已经消失。
在没有化学地图的情况下，蚂蚁依赖的是对旧路线的记忆，而不是寻找新的食物。科学家日前在《The Journal of Experimental Biology》上报告了这一发现。被捕获的蚂蚁错失了享用更甜大餐的机会，但这一策略或许使其在大自然中受益。在自然界中，蚁群会开发很多食物来源。同时受到信息素和记忆的导航，蚂蚁会更加灵活：即便降雨或时间的流逝将蚂蚁的信息素路径抹掉，它们仍能获取到经过检验是可靠的食物。
来源：中国科学报 徐徐
Abstract
Division of labour in social insects represents a major evolutionary transition, but the physiological mechanisms that regulate this are still little understood. Experimental work with honey bees, and correlational analyses in other social insects, have implicated juvenile hormone (JH) as a regulatory factor, but direct experimental evidence of behavioural effects of JH in social insects is generally lacking. Here, we used experimental manipulation of JH to show that raised JH levels in leaf-cutting ants results in workers becoming more active, phototactic and threat responsive, and engaging in more extranidal activity - behavioural changes that we show are all characteristic of the transition from intranidal work to foraging. These behavioural effects on division of labour suggest that the JH mediation ofbehaviour occurs across multiple independent evolutions of eusociality, and may be a key endocrine regulator of the division of labour which has produced the remarkable ecological and evolutionary success of social insects.
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