What are the common ants?
There are several thousand ant species in Australia, some haven't even been named yet! Ant identification is difficult, even for the professionals. The many species can be grouped in different ways. Other than using scientific classification, a common way to group them is by the type of food they prefer; sugar feeders, protein feeders or oil / seed feeders. However, many homeowners describe ants by the location they are causing the problem; indoor ants, outdoor ants or lawn ants.
The most commonly encountered species in and around homes are the black house ant, white footed house ant, argentine ant and big-headed ant. Species that tend to make a nuisance of themselves in the lawn include the green-headed ants and funnel ants.
Outdoor ants (that often come indoors)
Why are ants so difficult to control?
Ants are a social insects, which means that there are different castes (or types of ant) to carry out the different roles of the colony. The Queen runs the nest, producing the eggs which develop into larvae and finally into adult ants. In general there are three castes; the workers which look after the young and carry out most of the foraging and daily activities of the colony, the soldiers which defend the colony and the reproductives, which have wings. The reproductives are the new kings and queens which fly off to start new nests. However, in some species the reproductives do not have a mating flight and start a new colony by simply "budding off" the existing colony - they simply leave the nest with a few workers to set up a new nest nearby.
Nests may contain a single queen or multiple queens, depending on the species. Some species set up a single nest, other species may spread the colony over multiple nesting sites. To eliminate an ant problem the queen needs to be eliminated...... and with some species having multiple queens spread over different locations, this can be very challenging. So to get rid of your ant problem it is important to identify the species involved, so its nesting habits can be taken into account in any control program.
Identifying the species is the key, not only to understand the potential nest structure but also the likely location of the nest and their feeding habits. Knowing their feeding habits is important in achieving control, as often the best control product is a bait. With bait products you don't need to locate the nests. Ants feed on the bait (containing a slow acting insecticide), taking it back to the nest and spreading it around to the other ants through trophyllaxis (a process of sharing food). As a result, the bait can be passed to all nest members, including the queen, thus killing the colony. However, for baits to work, you need to choose the right food / bait for the ant species present. And just to make things more difficult, ants often change their food preferences throughout the year!
Where do they live?
Most ant species normally live outside, underground; under rocks and logs or in decaying wood. However, some species can become a real nuisance if they nest under paving, creating unsightly mounds of dirt and eventually under-mining the pavers. Some species can cause significant issues in the lawn if they become established; green-headed ants can give nasty stings and funnel ants can make lawns an unsightly mess. Although most species nest outside, a few species are also happy to nest inside your home; in wall voids, the roof space or under the home.
Should I be concerned?
Most ant species are normally just a nuisance rather than cause for concern, although they can cause food spoilage. However, a few of the smaller species can cause health issues if they get into hospitals or vet clinics and ants have been know to be the cause of some house fires when they get into plugs / electrical boxes.
However, there are a few species of ant that are found outdoors that can give a nasty sting / bite. Green-headed ants are perhaps the most common species that can give a nasty sting, although generally the sting area will calm down after a couple of hours. But there are some ants that can give a very painful sting, that can sometime cause the victim to go into anaphylactic shock. Without medical treatment, this can develop into a very serious situation. Many of these ants belong to the Bull ants species (also called Bulldog ants and Jack-Jumper ants).
These are big, aggressive ants with large jaws, capable of delivering multiple stings. They are fast moving and can sometimes be jerky in their movement making small jumps. These ants should be avoided!
Apply an ice pack if bitten followed by a commercial anti-sting cream. If an allergic reaction follows a bite, seek medical attention immediately. Pets can also react badly to Bull ant stings, so keep a close eye on your pet if stung and take to the vet if in doubt.
For more information on bull ants go to http://australianmuseum.net.au/Bull-ants
What can I do, to keep them out of my home?
1) The key preventative action is to reduce the available food - maintain good hygiene;
- Clear up any spilt food
- Clean down and under the oven / fridge regularly
- Do not leave unwashed dishes out overnight
- Do not leave pet food bowls out with food in or unwashed
- Food should be stored in tight “ant proof” containers
- Put rubbish into sealed bins and stack away from the house
2) You can reduce the number of ants around your house by creating "ant smart" gardens. Remove vegetation immediately surrounding the house. Avoid garden beds with wood mulch or straw next to the house. Keep any gardens next to the house dry (ants like moisture). Avoid using plants that attract aphids (such as roses) - many ant species "farm" the aphids, feeding on their sugary excretions.
3) As you know, ants can get through the smallest of gaps, so it can be virtually impossible to stop them getting into the house. However, if you have any obvious gaps in brickwork or around windows and doors, its certainly worth filling them in.
DIY pest control
DIY control of ants is not an easy process, simply spraying the ants you see with a household aerosol will do no more than kill a few ants. It is unlikely to kill the queen or the majority of ants back in the nest. Without killing the Queen the ants will eventually return....... normally sooner rather than later! Some of the consumer ant baits for "sweet feeding" species can be useful, but you need to correctly identify the species for effective results. Although the outdoor "barrier" sprays available in supermarkets and hardware stores are reasonably effective in providing long term protection from cockroaches and spiders, they are generally quite ineffective on ants and shorted lived. These use old "repellent" technology which does not work well on ants.
Members of the public (and many pest control companies!) often struggle to control ant problems due to the high level of insect understanding required to gain control. In addition, products available to consumers are quite limited (in that they use old technology). Therefore, it is not surprising that ants are considered the number one nuisance pest in many countries.