Species most commonly found in dwelling placesBlack-Grey Garden Ant (Lasius niger)
SizeWorkers (female): 5 mm
Males: 6 mm
Queen: 13 mm
Special characteristicHigh level of social organisation in the ant colony
NutritionMostly carbohydrate-containing diet
Nesting siteWall cracks on houses, in the soil, never inside the house
CommunicationThrough scents
DamageHollowing out of areas under footpaths and terraces
ControlScent barriers and ant bait stations


Ants are one of the most commonly found insects in the world, both in terms of species diversity and number. The majority of the roughly 8,800 species of ants are found in tropical and sub-tropical regions. They can reach very high population densities, especially in the tropics. Ants make up an estimated one-third of the animal biomass in the Amazon rain forest. Although there are only 180 ant species in Europe, ants play a significant role in our ecosystem as well. Ants distribute nutrients in the ground, kill harmful insects and serve as a food source for other animals, especially for birds. However, ants can also be very annoying when they make their way into residential buildings.

Appearance and Behaviour

Ants have a characteristic appearance with a head that is set off from the rest of the body and a large abdomen. All ants have angled antennae made up of a long base element and a segmented end.

From a scientific classification standpoint, ants, together with bees and wasps, belong to the Hymenoptera order. Ants are characterised by a high level of social organisation. Ant colonies are made up of various groups of ants that are differentiated by their body structure and behaviour: females capable of reproduction and only winged at certain times; winged males; sterile, wingless females – the workers – and the queen. The queen is the only ant in the entire colony that produces eggs. The numerous workers are responsible for all the other tasks, such as nest-building, defence, procuring food and caring for the brood. The sole job of the males during their short life cycle is to mate with the queen. The winged females only appear for a short time. After mating, they lose their wings and form new ant colonies. The wingless workers are generally the only ants that can be seen as they busily search for food, often far away from the nest. Ants have the most advanced form of scent-based communication. The route to a food source is marked by a trail of scents that are released from special glands. The scent marker indicates the quality and location of the food. Ant columns form along the scent trails. Liquid food is transported in the so-called “social stomach”. Solid food, such as a caterpillar, is taken back to the nest by one ant or a group of ants, either whole or after separating it into parts. In the nest, the solid food must be chewed by the larvae before the adult ants are able to eat it. This method is used to distribute food among the entire colony, including the brood (larvae) and the queen.

Damage Caused by Ants

Domestic ant species spread aphids in order to collect their sugary excrement. Ants are a nuisance when they build their nests on lawns or in the cracks between rocks on terraces. Ants searching for food can also make their way into kitchens, pantries and storehouses. When crawling over food, ants can spread bacteria and spores. The black-grey garden ant (Lasius niger) and the brown wood ant (Lasius brunneus) are the two species that most commonly make their way onto balconies, terraces and into residential dwellings. A species of ant introduced to our parts, the Pharaoh ant (Monomorium pharaonis), can be a hygienic hazard. The Pharaoh ant eats materials that contain proteins and can cause serious hygienic problems in hospitals when they invade wound tissue. Controlling this species is difficult and should be left to professionals.

The Black-Grey Garden Ant and the Brown Wood Ant

The black-grey garden ant often finds its way into homes, especially during spring when the food supply is limited outdoors. However, they do not build their nests in homes. The workers of this ant species measure 2.5 to a little over 4.0 mm in length and their entire bodies are black-brown in colour. Their antennae are yellow-brown at the base. The brown wood ant is also known to build its nests in rotten wooden beams and thereby cause damage to other areas of wooden structures, making this species of ant a possible pest for materials. The brown wood ant is smaller than the black-grey garden ant. Its chest, legs, feelers and jaws are yellow-brown. The head and abdomen are darker. Both ant species primarily feed on carbohydrates.

Control Indoors and on Terraces

When ants are found in a residential dwelling, the first step is to locate the point of entry. Filling in cracks and gaps can often prevent further intrusion.

An environmentally friendly way to control ants is to set up bait stations containing an insecticide. The ants take the bait, which contains carbohydrates, go back to their nest and feed it to the other ants, the brood and the queen. The insecticide is dosed to have a delayed effect so that it can be passed on to the colony. This method combats the entire nest and not just individual ants, which would quickly be replaced by new offspring.

Essential oils, which are available as liquids or powders, can be used to disrupt communication along scent trails or, when applied to the nest, within the colony. Ants will cease to visit areas that have been treated with such oils. These oils can be used to create a scent barrier on balcony doors or on terraces. When applied to a nest, the scents from the essential oils cause sufficient disruption to lead the colony to abandon the nest.

Aeroxon Ant Bait Station*

Eliminates ant infestations completely and cleanly

Ant Bait Station*

Aeroxon Ant Stop*

Safe and effective control of ants and ant colonies in and around the home

Ant Stop*

Aeroxon Glue Band for Trees

For fruit and ornamental trees

Glue Band for Trees