Black Garden Ant (Lasius niger)

Black Ant - Chesterfield Pest ControlThere are many thousands species of ants known to man, many of their habits and the food they eat differ considerably. The most common ant in Britain is the Black Garden Ant or otherwise known as the Common Black Ant which prefers a diet of sweet foodstuffs. They are usually seen in our gardens, around walls and under stones and paving. Occasionally they enter buildings.

Scientists believe ants gradually evolved from wasps more than 100 million years ago.

Ants like all true insects have three main body parts: head, thorax and abdomen.


  • The Black Ant worker ant is between 3-5 mm long, and despite its name is dark brown in colour.
  • The Black Ant queen is around 15mm long and mid brown in colour.

Life Cycle

Mating of black ants takes place over a short period of time normally during warm summer days in July and August. The mating nearly always occurs on the wing and lasts a few hours, during which time large swarms of ants can be seen flying around. After mating the male dies, and the newly fertilised queen will begin to search for a suitable nesting site where she will create a cell for her new colony and overwinter there. Occasionally a newly fertilized queen may return to her existing colony where she is accepted as an extra queen. She will normally lay her first eggs in late spring, and it normally takes about 3-4 weeks for the white legless larvae to hatch out. The larvae are then fed with a salivary substance from the queens mouth, this period will normally last about three weeks, following which the larvae pupate. This first generation of worker ants will emerge from their cocoons within two weeks and take on their duties of foraging for food such as dead insects, seeds, nectar and sugary secretions from greenfly . The workers will also be responsible for rearing the young, keeping the nest clean and removing any dead ants or debris. Approximately 90% of the workers are involved in rearing the young and tending the nest, and the other 10% forage for food. The queen will now spend all her time in the nest laying eggs and tending to her young.

  • Eggs hatch in 3-4 weeks.
  • Larval stage about 3 weeks
  • Pupal stage 1-2 weeks

Reason for control

Black worker ants can become a real nuisance, especially during the summer months, when they frantically forage for food and water. They will travel a considerable distance in search of a suitable food supply marking their trail along the way and communicating with other ants by tapping them with their antennae. Their preference being for sweet foods. They will enter areas like kitchens, and food preparation areas, whilst foraging, and where sweet substances are found they will soon be present in numbers .

Black ants can also become a nuisance on the outside as well. They excavate the soil making it dry. Cracked paving and poorly laid flag stones will provide ants with suitable conditions to breed in abundance.

Black ants cultivate greenfly whilst feeding on the sweet sticky secretions they produce. In doing so they sometimes transmit viruses from diseased plants to healthy ones

Control measures

Black garden ants do not present any major threat to our health, but can become a real nuisance when they enter our homes and workplaces. Effective control can only be achieved by destroying their nests with insecticide. Applying a suitable residual insecticide around the area of the nest or to the places where they are entering the property should have a considerable impact on the colony and reduce activity. Particular attention should be given to air vents, doors, windows and cracks and crevices. Nests can sometimes be traced by following ant trails.

Any insecticidal products used should be applied with extreme caution and the instructions given should be fully adhered to in the interests of your own safety. Where a problem is severe professional help should be sought.

Created by DS Creative