Ants as scavengers and herders

So far I have overlooked two important aspects of garden ant foraging behaviour, mainly due to the lack of suitable photos. Yesterday, I spotted a strange large insect walking on the concrete yesterday, when I got closer I realised it was actually a dead bluebottle being dragged by a garden ant (Lasius niger). Another ant run frantically back and forth, but a single one seemed to do most of the work. The strength of an ant is quite formidable, able to lift or drag objects much heavier than themselves. This illustrates the role of ants as scavengers. Any dead animal will either be dragged to the nest or bits of it will.

The second aspect is one of the most surprising of ants - showing their adaptability -  but also a reason why they are hated by many gardeners: their role as aphid herders. Ants behave as farmers with their aphids and will try to keep the numerous aphid predators at bay as well as milking their honeydew. This is considered a mutualistic relationship and aphids also benefit from the behaviour. Even when aphid predators are excluded, aphids multiply faster in the presence of ants. The photo, taken today, shows two garden ants stimulating Elder Aphids (Aphis sambuci) to excrete their honeydew. Elder aphids form very compact groups on tender growing stems of Elder.