PDF(Pubmed)
Abstract：
Urbanisation alters biodiversity patterns and threatens to disrupt mutualistic interactions. Aside from pollination, however, little is known about how mutualisms change in cities. Our study aimed to assess how urbanisation affects the protective mutualism between ants and aphids, investigating potential behavioural changes in mutualistic ants and their implications for aphids in urban environments. To do so, we studied the protective mutualism between the pink tansy aphid (Metopeurum fuscoviride) and the black garden ant (Lasius niger) along an urbanisation gradient in Berlin, Germany. In nine locations along this gradient, we measured aphid colony dynamics and proxies for parasitism, quantified the investment of ants in tending aphids and conducted behavioural assays to test the aggressiveness of ant responses to a simulated attack on the aphids. We found that aphid colonies flourished and were equally tended by ants across the urbanisation gradient, with a consistent positive density dependence between aphid and ant numbers. However, ants from more urbanised sites responded more aggressively to the simulated attack. Our findings suggest that this protective mutualism is not only maintained in the city, but that ants might even rely more on it and defend it more aggressively, as other food resources may become scarce and more unpredictable with urbanisation. We thereby provide unique insights into this type of mutualism in the city, further diversifying the growing body of work on mutualisms across urbanisation gradients.
摘要：
城市化改变了生物多样性模式，并有可能破坏互利互动。除了授粉,然而,人们对城市中的共生关系如何变化知之甚少。我们的研究旨在评估城市化如何影响蚂蚁和蚜虫之间的保护性共生，调查互惠蚂蚁的潜在行为变化及其对城市环境中蚜虫的影响。要做到这一点，我们研究了柏林城市化梯度中粉红艾菊蚜虫（Metopeurumfuscoviride）和黑花园蚂蚁（Lasiusniger）之间的保护性互惠，德国。在这个梯度的九个位置，我们测量了蚜虫的菌落动态和寄生代理，量化蚂蚁在抚育蚜虫方面的投资，并进行行为分析，以测试蚂蚁对蚜虫模拟攻击的反应。我们发现蚜虫群落繁盛，在城市化梯度上同样受到蚂蚁的照料，蚜虫和蚂蚁数量之间具有一致的正密度依赖性。然而,来自更城市化地点的蚂蚁对模拟攻击的反应更积极。我们的发现表明，这种保护性的互惠主义不仅在城市中得以维持，但是蚂蚁可能会更依赖它，更积极地保护它，随着城市化，其他粮食资源可能变得稀缺和更不可预测。因此，我们为城市中的这种互惠主义提供了独特的见解，进一步使城市化梯度中日益增长的相互关系工作多样化。
