Ants

Taxonomy

Ants belong to the Hymenoptera order. There are many species that cause various problems in urban areas, the main ones being Monomorium pharaonis (Pharaoh’s ant) and Lasius niger (black ant).

Biology

They live in organized colonies. Their nests are in tree trunks or in the form of underground chambers in the ground. In the nest live the egg-laying queens, workers, larvae, males and hoplites (soldiers). They are fully metamorphosed (they undergo complete metamorphosis), i.e. their developmental stages are egg-larva-pupa-bloom. The queen is the largest ant in the nest and never comes out. The queen emerges during swarming as a reproductive swarmer and for this reason, at this stage, she bears wings and flies out of the mother nest. During swarming, many other ants follow her and build a new nest with the new queen. This is only done once a year in each nest, during the summer months.

Monomorium pharaonis

It is an ant with a small body. Workers are 1.5–2mm long and brownish-yellow in color. They prefer hot and humid conditions, which is why in many areas they are confined inside buildings. They have many queens in each nest. Foraging workers leave the main nest with the brood to establish peripheral colonies when they feel threatened. They often “fill” the building. The biological cycle of this species does not exceed two months, while the queens live for several years.

Lasius niger

Workers are 2–5mm long and dark brown/black in colour. Black ants make nests outdoors, in walls, under paving stones, etc. They travel long distances for food and water and usually enter homes, where control is only necessary when they become a serious problem. The biological cycle of the workers ranges from 50 to 70 days. A black ant colony has a single queen and a few thousand individuals.

Public health

They can carry germs to clean areas as they come from afar and may have passed through waste or other contaminated areas. Many times they make nests in electrical panels and cause problems.

Modes of Management

Prevention: there should be no openings (eg open windows, openings under doors, etc.). Ants “invade” the building for food or water. We therefore keep food well packed and closed (e.g. in glass jars). One of the required actions is the cleaning of work benches in food areas and dining rooms.
Monitoring: It is recommended to use bait traps to record their presence.
Treatment: In order to combat ants, contact insecticide sprays are carried out directly on the nests, residual sprays on the places where we see them moving while applying, and special non-toxic anticidal gels.