Laboratory of Apiculture and Social Insects, Department of Biology and Environmental Science, University of Sussex, Falmer, Brighton BN1 9QG, UK.
J Exp Biol. 2013 Jan 15;216(Pt 2):188-97. doi: 10.1242/jeb.076570. Epub 2012 Sep 12.
Ants are central place foragers and use multiple information sources to navigate between the nest and feeding sites. Individual ants rapidly learn a route, and often prioritize memory over pheromone trails when tested on a simple trail with a single bifurcation. However, in nature, ants often forage at locations that are reached via more complex routes with multiple trail bifurcations. Such routes may be more difficult to learn, and thus ants would benefit from additional information. We hypothesized that trail pheromones play a more significant role in ant foraging on complex routes, either by assisting in navigation or route learning or both. We studied Lasius niger workers foraging on a doubly bifurcating trail with four end points. Route learning was slower and errors greater on alternating (e.g. left-right) versus repeating routes (e.g. left-left), with error rates of 32 and 3%, respectively. However, errors on alternating routes decreased by 30% when trail pheromone was present. Trail pheromones also aid route learning, leading to reduced errors in subsequent journeys without pheromone. If an experienced forager makes an error when returning to a food source, it reacts by increasing pheromone deposition on the return journey. In addition, high levels of trail pheromone suppress further pheromone deposition. This negative feedback mechanism may act to conserve pheromone or to regulate recruitment. Taken together, these results demonstrate further complexity and sophistication in the foraging system of ant colonies, especially in the role of trail pheromones and their relationship with learning and the use of private information (memory) in a complex environment.
蚂蚁是中心觅食者，它们使用多种信息源在巢穴和觅食地点之间导航。个体蚂蚁可以迅速学习一条路线，并且在测试具有单个分支的简单路线时，通常优先考虑记忆而不是信息素痕迹。然而，在自然界中，蚂蚁经常在通过具有多个分支的复杂路线到达的地方觅食。这样的路线可能更难学习，因此蚂蚁将受益于额外的信息。我们假设，在复杂路线上觅食时，信息素痕迹在蚂蚁觅食中发挥着更重要的作用，无论是通过协助导航还是路线学习，或者两者兼而有之。我们研究了在具有四个终点的双分支路线上觅食的黑褐林蚁工人。交替（例如左右）与重复（例如左右）路线相比，路线学习速度较慢，错误更多，错误率分别为 32%和 3%。然而，当存在信息素痕迹时，交替路线上的错误减少了 30%。信息素痕迹还有助于路线学习，从而减少了没有信息素的后续旅程中的错误。如果经验丰富的觅食者在返回食物源时犯了错误，它会通过增加返回途中的信息素沉积来做出反应。此外，高水平的信息素痕迹会抑制进一步的信息素沉积。这种负反馈机制可能会起到保存信息素或调节招募的作用。总之，这些结果表明蚂蚁群体的觅食系统更加复杂和复杂，尤其是在信息素痕迹的作用及其与学习以及在复杂环境中使用私人信息（记忆）的关系方面。
