Ants cause problems
primarily when they forage in buildings for food or water and when they
construct nests in buildings and gardens. When searching for food, they
can be attracted to a wide range of products with different species
preferring sweets, meats, fats or oils. They will also
indoors for water during dry periods. When desirable items are found
many species will recruit fellow nest mates to help gather the food
and return it to the nest. This can result in large numbers of ants
appearing over a short period of time.
Ants can be
a nuisance when attempts are made to establish plants through direct
seeding. Workers will forage for the newly planted seeds, removing them
to their nests and causing reduced germination.
Some ants build
nests in walls and foundations, or indoors in potted plants, enclosed
areas, and even in cavities in toilets and sinks. In almost all cases
nests are limited to pre-existing cavities or spaces between objects
or in rotten wood and seldom will ants attack solid structures. Thus
they generally will not cause structural damage to buildings but will
take advantage of existing deterioration.
activity can result in excavated soil being deposited in gardens and
on brickwork. In most cases this causes little property damage but some
species, especially species of Aphaenogaster
can form large numbers of chambers close to the surface. These chambers
can cause soil to become soft and uneven, causing serious problems when
found in golf courses or some types of pastures or crops. A few species
will occasionally attack electrical wiring, apparently being attracted
to either the insulation or the magnetic fields produced by the wires.
In these situations extensive damage has occurred.
Ants often move
nest sites when disturbed, or with a change in food supply. This can
make control and remove of ants difficult. They may leave for short
periods only to return later when a new food source is located and they
can recolonise from nearby nests very quickly.
of ants pose serious health threats to people who are sensitive to their
stings. These include species of Myrmecia
in southern regions and Odontomachus
in northern areas. In extreme cases hospitalisation may be required.
Other species are known to carry diseases and can pose a threat in hospitals
and veterinary clinics (some introduced species of Monomorium
and the Argentine ant, Linepthema
). Fortunately these cases are uncommon in Australia and
in general ants are mainly a nuisance pest rather than a health problem.