Why Red Wood Ants Are Good for the Forest

Nov 2

2 min read

Updated: 1 day ago

In Germany, red wood ants are sometimes called the health police of the forest. That is no exaggeration: few animals do as much for a forest as a healthy population of red wood ants. Here is why they matter so much.

Natural pest control

Red wood ant workers on their mound with prey — Workers bringing prey back to the nest.

Red wood ants catch enormous numbers of insects. A large nest with a million ants needs around 30 kg of insects a year, roughly ten million prey animals. Among them are caterpillars of forest pests such as pine moths, winter moths and oak leaf rollers, which are rarely found close to a wood ant mound. In forestry, wood ant nests have even been introduced into forests on purpose to help control pests.

Honeydew farmers

About two thirds of their food is honeydew, the sweet liquid produced by aphids. The ants protect their aphids against enemies such as ladybirds, and in return they collect the honeydew high up in the trees.

Gardeners of the forest

Many forest plants, such as cow-wheat, have seeds with a small, nutritious appendix. Wood ants carry these seeds to their nest, eat the appendix and leave the seed, which can grow into a new plant away from the mother plant. This way, ants help plants spread through the forest.

Better soil

By digging, carrying in plant material and breaking down waste, red wood ants loosen and enrich the soil. Around their nests, the soil can even become less acidic.

Food and shelter for others

Red wood ants are food for many animals, such as woodpeckers, other birds, lizards and toads. Their mounds also house dozens of other species that live nowhere else, from beetles to the tiny shining guest ant.

Threats

In the Netherlands, wood ants declined sharply on sandy soils in the late 1980s because of acid rain. They have recovered slowly, but nitrogen deposition can still harm their nests. Road building, insecticides and changes in forest management are threats too. That is why red wood ants are protected in countries such as Germany and Switzerland.