Yellow Meadow Ants

Although quite common in old pastures in the south of Britain, these mounds are rare in the north but Haddon has them in abundance. Here they are of considerable size, testimony to the untouched nature of the land, as these ants only produce mounds in unworked grassland, and of the centuries that the colonies have lived here, as a large ant-hill may only have as a little as a litre of soil added to it each year.

The ant-hills greatly increase the environmental diversity of the grassland, as the mounds have a different soil composition, nutrient and water content to that of the grassland between them and as they also exist at a different temperature to their surrounding land due to their shape and height presenting different aspects to the sun. The result is that they create a secondary habitat within the land, creating ‘fields of force’ which considerably affects the patterns and behaviour of the plants, animals and micro-organisms in the pasture.

Of particular importance is the soil-heaping which creates permanent patches of bare soil allowing regeneration sites for plants such as the winter annuals and mosses which would normally be absent from the surrounding sward; and that the ants themselves provide important food sources for birds in the winter, such as the Green Woodpecker and BAP priority species the Grey Partridge.

A large mound can support between 8000-40,000 ants and they normally spend their life underground farming underground aphids, which feed on the roots of the specific plants, such as Wild Thyme or Common Rock-rose that clothe their mounds. The ants ‘milk’ these aphids for a honeydew which provides them with a sugar rich diet creating a relationship of perfect mutual benefit, ‘mutualism’.

It is very tempting after a long walk to take rest on one of these comfy mounds, but be warned, if disturbed, a Yellow Meadow Ant can deliver a bite into which it expels formic acid from its abdomen, so we highly recommended that you avoid sitting on their hills!

Life Cycle:

The Yellow Meadow Ant lives in organised social colonies consisting of a Queen, a few males and a large number of workers which are non sexual females. During the summer the colonies release winged reproductive males and future queens. The trigger for this synchronised ‘Nuptual flight’ is warm humid air, typically after a rain shower. After mating, the female lands on the ground, sheds her wings and sets off to find a suitable place to start a new colony. His job now done, the male dies within a few hours. The new queen has enough sperm to fertilise all her future eggs so she will not mate again but instead will remain in captivity in her hill for the rest of her life of ten years or more.