Pharaoh's Ant

(Monomorium pharaonis)
Pharaoh's Ant

Habitat

Tropical species found only in heated buildings in the UK. Small, mobile and active at all times of the day. Form large, apparently unstructured, nests in cavities and heating ducts. Many queens per nest. Workers seen in distinct trails between nest and food sources. Forage on wide range of foods and need access to water. Infestations spread by 'budding', groups of workers and sometimes queens leaving the main nest with brood to form satellite colonies.

Biology

Egg - larva - pupa - adult. Eggs - laid by queens within nest, hatch in about 1-2 weeks. Larvae - legless grubs fed by young workers in nest, full grown in about 3-4 weeks. Pupae - develop in about 2 weeks guarded by workers in nest. Adults - workers wingless, 2mm long, yellowish, live about 10-12 weeks. Queens winged 4-5mm normally stay in nest, live up to 10 months. Minimum development temperature 18°C, optimum 30°C.

Severity

May carry disease organisms. Contamination of food and sterile materials. Can penetrate packaging due to small size. Ability to travel through ducting and building structure means infestations can become very widespread. Satellite nests may be transported from one building to another.

Solution

Use of grain or gel bait insecticide to target queens. Only to be undertaken by qualified technicians.

Interesting facts

A colony can maintain several hundred queens which leads to multiple colonies, making control very difficult if not treated correctly.