Ants belong to the order of insects known as Hymenoptera which includes some of the most highly evolved insects. They have a caste system in which nest building, nursing of young and foraging for food is undertaken by workers (sterile females). Reproduction is performed by fertile females (queens), and males are responsible for fertilisation of the queens.

All ants are characterised by the following:-

• A narrow waist (pedicel) of one or two segments between the abdomen and thorax.
• Biting mouthparts.
• Elbowed antennae.

When wings are present, there are two pairs; each linked by a minute row of hooks. There are three main pest ants in the UK.

The Black Garden Ant (lasius niger)

This is by far the most common ant that we are called upon to deal with. This ant lives in a nest and in its endeavour to find food, will infest any type of premises including domestic kitchens, hospitals, offices and shops, in fact almost anywhere they can find a suitable food source. This ant is dark brown to black in colour, approximately 5mm in length, with one small waist segment. The nest will often be found under paving stones

The Pharaoh Ant (monomorium pharaonis)

This ant is tropical in origin although it is well established in this country now. They live in nests which can be found in wall cavities and voids where hot water pipes run, these are usually inaccessible. They are yellow brown in colour often with a darker abdomen. They are approximately 2mm in length and have two waist segments. They will normally be found in centrally heated buildings such as hospitals, blocks of flats and restaurants.

Roger’s Ant (Hypoponera punctatissima)

This ant is sub tropical in origin, and prefers damp locations. They can normally be found in crevices around drains. They are not confined to heated premises. They would normally be found in zoos and factories; they are not normally classed as a pest of domestic premises.

There are some other species of ants in the UK, one of these is the Ghost Ant. This ant is not so common as the other pest species although they can be a major nuisance if they do infest premises.