Where do they live?

Black Garden Ants nest mainly in dry soil and humus. Although their nests are most often noticed in gardens – in flower beds, lawns, and under paving stones – they are also common in dry grasslands and heaths.
From their nests, they forage widely for food along scent-marked trails across soil and ground vegetation, and – most noticeably – across paved surfaces and into houses, where they are attracted to sugar and crumbs.
Outside human habitation, they feed on many things: small live insects, dead insects, nectar, seeds, etc. They also feed on the sugary secretions produced by aphids, some other sap-feeding insects and certain caterpillars, and often tend them to protect the source of this food from predators.

Biology

Ant societies are centred upon a complex nest that arises after the mated queen has established a smaller starter nest beneath the soil. The queen rears the first brood of larvae within the nest, feeding them on saliva.
These larvae mature then pupate to form the first worker ants. While she is rearing the first batch of larvae, the queen uses the reserves from her flight muscles etc as food. The colony then grows rapidly with the queen continuing to lay eggs which are tended and fed by the workers.
The ants feed on nectar, seeds and small insects, aphid and coccid honeydew etc, and the nests can remain viable for many years. The males and females exploit the thermal currents to rise and mate in mid-air.
Typically mating flights occur in August, following stormy weather. Very few of these fertilized queens survive to set up colonies.

Significance

Foraging worker ants cause a nuisance as they travel widely in search of food, following well-defined trails and clustering around the food source. Primarily a nuisance pest, the Black Ant does not pose a significant threat to public health, although they are obviously an unpleasant sight and may damage food used for human consumption.

Control

Accessibility to the nests may be restricted and yet this is the key to gaining control of the infestation.
Following trails of the worker ants back to the nest should help to locate their position.
Gel baits are now available for black garden ants. These rely on the worker ants picking up the bait and taking it back to the nest to feed the queen. Therefore baits should not be used in conjunction with residual sprays.
Baits are best placed where the ants are foraging - in and around nest entrances, adjacent to ant trails and in the cracks and crevices between paving slabs, concrete foundations etc.
Alternatively, residual insecticidal treatments can be applied in or around the nest. Barriers of insecticide can also be utilised around strategic points on the property to prevent foraging workers gaining access.

The Ant   Pharaoh’s ant, Monomorium pharaonis   Key features

Monomorium pharaonis, or pharaoh's ants as they are commonly known, are a common species of ant that can be found in urban environments around the globe.
Monomorium pharaonis originated in Central and West Africa though has managed to spread over the last century mainly due to the increase in international trade, because of this it is known as a tramp species. It has now established itself as one of the premier ant pests in urban environments; this is mainly due to its biology, aspects of which it shares with two other tramp species that are also considered major pests. The main concern with these species is their potential as a vector for disease when hospitals are infested as well as the general nuisance factor.
The workers of this species of ant are only around 2 mm in length, with the queen being larger between 3 and 4 mm long, while the males are around 3 mm. The colouration of the workers is light yellow with a darkish abdomen. The characteristic of the Pharaoh's ant appearance is the double 'waist' known as the pedicel, which in fact constitutes the first segments of the abdomen

Biology

Monomorium pharaonis is a highly polygynous species i.e. there are many queens within a single colony. Colonies are also polydomous (live in multiple nest sites) forming a network of trails between nests.
These two aspects of pharaoh's ant biology mean that colonies can reach mammoth proportions.Queens lay approximately 350 eggs. Larvae hatch after 2 weeks and are fed by workers.
After a number of skin changes pupation takes place. Full grown ants hatch soon afterwards depending on temperature. Colonies are 50,000 to 1000,000 strong with many queens, workers and male pharaoh ants that make it so aptly adapted to living in urban environments as well as enabling it to extend to almost every corner of the globe.
Despite being a tropical species they manage very well in colder climates through the advent of central heating.

Control

The use of conventional insecticides against Pharaoh's ants is not recommended as this will almost certainly cause worker ants to form satellite colonies and thus actively spread an infestation deeper into the building.
Granular or gel baits are available for Pharaoh ant control.
These should be laid where the ants are actively foraging and particularly with this ant species, treatment of adjacent properties may also be advisable.