Category Archives: Pest Library

#1 Nuisance Ant Species in Western Australia – Coastal Brown Ants

Big-headed ants, also known as Coastal Browns, or Brown Coastal are a major nuisance ant species in Western Australia.

They are an urban pest and are often seen in lawns and in brick paving which they tend to undermine.

The presence of two very different-sized ‘castes’ (types determined by their function) of worker ants, that is:

Smaller ‘minors’ — 2 to 3mm long

A larger ‘major’ caste — 3.5 to 4.5mm long, which has a very obvious, much larger head and which makes up about 1% of the population.

The ‘major’ caste of worker ants are not primarily soldiers for defence. Instead, their powerful jaws are used for cutting up large pieces of food into small pieces which can more easily be transported back to the nest by the more numerous minors.


There are multiple queens in the nests which are interconnected. New colonies are formed by budding whereby one or more queens with attendant workers leave an existing nest and walk to a nearby location. Rarely are new nests established by flying, mated queen ants.
While these ants can sting, the sting does not cause discomfort to people. Big-headed ants are particularly active in late summer, autumn and early winter.

They nest outside in the ground and only occasionally invade buildings when populations outside are very high. However, invasions of buildings can be severe.

These ants prefer meat or fat/oil-based foods.
Big-headed ants can form ‘super-colonies’ when their interconnected nests act as a single colony.


Infestations of big-headed ants are characterised by lines of inter-connected holes and small mounds of excavated soil. Excavations can be so extensive that brick paving is destabilised and the roots of plants and the lawn can become so aerated that the plants subsequently die by drying out. Often the small worker ants are hard to see, but food put out for pets can become covered in ants.
Look for two distinctly different-sized ants on a food source, with the larger worker ants having a disproportionately larger head.

Often referred to as ‘white ants,’ termites play an important role in nature, a few species attack man-made wooden structures and objects, earning themselves a reputation as the most destructive timber pest known to man.

Subterranean termites usually have to maintain contact with the soil to obtain sufficient moisture to survive. They live together in a colony and are divided into various castes, each with a specific duty. Worker termites are by far the most numerous of the castes. They forage for food, care for the young and build the nest. The workers are responsible for damage to timber caused in their search for food, which consists mainly of cellulose, sugars and starches present in the timber.

Protection of the colony is the duty of a relatively small number of soldier termites. Nature has equipped these soldiers with physical and chemical weaponry to help repel invaders. A further caste consists of the reproductive termites responsible for the propagation of the species. These reproductives grow wings and are known as alates.

Once a year, usually in early summer on a warm and humid evening, they swarm from the nest. After a short flight, these males and females shed their wings prior to mating. Most of these potential “king and queen” termites either fall prey to birds, lizards, ants and spiders, or die from exposure before they can find a suitable location. But, if they find a suitable environment, a new colony will result, which, after many years, may contain over one million termites.

Whenever termites leave the soil in search of food, they construct mud tunnels to protect themselves from predators and to ensure a high level of life sustaining moisture is maintained within the workings.

Termites do not like the light so they remain inside the wooden components of your home and eat away everything but the very edge. Sometimes only a thin layer of paint remains. It is possible to ascertain the presence of termites by tapping gently on timber beams, newel posts, skirting boards and other structural timbers. If you hear a hollow sound there is every possibility you have a termite problem.

Apart from widespread and sometimes pathological fear of spiders, the most common reason for control is the elimination of unsightly webs.

Spiders can be readily distinguished from insects: they have eight legs instead of six and they have two body segments instead of three – the head and thorax are fused into one unit which contains eyes, mouthparts and legs. The abdomen section is soft and houses the reproductive organs, the silk glands and spinnerets, and the respiratory openings which are visible on the under surface like the pages of a book. This large surface area achieves the transference of oxygen into blood. There are usually four pairs of eyes which are arranged in a pattern which is constant for each species and is therefore an aid to identification. The fine hairs on various parts of the body are said to be sensitive to taste, touch and vibration.

Most spiders, being nocturnal, are seldom seen during the day unless disturbed. Those which depend on webbing to snare their prey seldom move far and hide in a crevice, curled leaf or appear camouflaged as twigs. Hunting spiders such as the huntsman are not dependent on webs for food.

Whether the spider traps prey in a web or hunts to capture it, the victim is injected with venom through the fangs. This immobilises the prey. Most species can survive for months without food. This is just as well, as insect prey is usually scarce in the cold winter months.

Silk or web is produced from glands in the abdomen and deposited through spinnerets. In some species, spiderlings let out sufficient web into the air to lift them up on the breeze and carry them away.

Cockroaches are survivors from around 300 million years ago. They are one of the longest surviving arthropods on the planet and it is estimated that they have now developed into more than 36,000 species variations although very few – maybe only six – are considered as domestic and commercial pests. A decapitated cockroach can survive for up to 72 hours.

All cockroaches have flat bodies, enabling them to hide under bark, in crevices and run under doors.  Their six legs are almost even in length and the antennae are long. They begin their lives as eggs that hatch into a flightless larva which shed their skins several times as they grow. Adults also cast their skins, develop wings and can live for up to 3 years. Although they have wings, adult cockroaches are more likely to run than fly which, along with their size and speed, makes them a genuine creepy crawly.

The eggs are carried by the female in a capsule and hatching larvae grow through a series of between 5 and 12 moults. The larger species become adults in 9-12 months but the German cockroach can mature in 40 days and, with up to 40 eggs in a capsule, the ‘family’ could number 20,000 in a year.

The main pest species in Australia are:

German Cockroach: Adults are 20-25mm in length and honey coloured. German cockroaches prefer warm kitchens or storerooms inside buildings.

American CockroachAdults can grow up to 55mm and are deep red/brown in colour. Americans prefer moist areas, both inside and outside and can readily flies in warm climates.

Other Australian Natives: There are hundreds of species, mostly found in gardens, but these are not generally considered as pests.

All cockroaches avoid light and prefer warm, moist situations close to a food source. Their indiscriminate feeding in such areas as sewers, drains and garbage areas brings them in contact with disease organisms associated with dysentery, typhoid, hepatitis and tuberculosis. Cockroaches are also known to produce allergic reactions in humans and, in some instances, severe asthma attacks.

The black Portuguese millipede, Ommatoiulus moreleti, is a native of Portugal and was accidentally introduced to Australia, first appearing in South Australia in 1953. They have since invaded all the southern mainland states.They are attracted to light and will enter buildings at night, although once inside they do not breed and will eventually die.

While there is no evidence they affect human health, they can occur in plague numbers, and can contaminate food and infest carpet and bedding. Portuguese millipedes are herbivorous, which means in plague proportions they may also destroy seedlings and fruit and vegetable crops.

When disturbed a millipede may release a pungent and distasteful yellowish secretion which discourages predators, such as birds. Note: the secretion may stain skin or clothes and is extremely irritating if rubbed into the eyes. However as it is composed of organic chemicals called quinones, it quickly breaks down in water.

Mature black Portuguese millipedes are smooth and cylindrical, 20-45 mm long and slate-grey to black in colour. Juveniles are light brown and striped. Juveniles hatch from eggs in the soil and reach maturity in two years.

During hot dry weather they will hide in the soil, however rain in spring and particularly in autumn will stimulate activity and breeding.

There are many species of native bee in Australia. Most are solitary bees that raise their young in the ground or in hollowed timber. We have ten species of social bees native to Australia that do not sting!

Honeybees are part of the family apidae, the most recognizable example of which is the European Honeybee. These bees were introduced to Australia for honey and crop pollination. Not surprisingly, feral colonies are now established in most parts of the country.

The European Bumblebee has not yet been found on the Australian mainland but feral colonies have spread to New Zealand and Tasmania. Bumblebees are considered superior pollinators to their Honeybee cousins. It is suspected that the entire Tasmanian population is descended from a single fertilised queen.

Honeybees are social insects that live in colonies called hives consisting of a queen, drones and worker bees.

Bees are almost totally deaf and rely mostly on their sense of touch. In a single colony there can be as few as 5,000 or as many as 100,000. After mating, the queen lays up to 3,000 eggs per day. Worker bees are always female. Their roles are varied and include foraging, fending off predators, feeding other bees and larvae, ‘house’ cleaning of cells and clustering to create beeswax.

Bees can sting to defend themselves, their hive or their young. Unlike wasps, the bee dies after stinging. The abdomen continues to pump poison after the initial sting which should be removed. Some people are allergic to bee stings.

Swarming occurs when a new queen leaves the hive, followed by the drones. She will mate with up to twenty drones which will give her enough sperm to last her lifetime (about two years). The queen may return to the hive and replace the old queen, but sometimes she will fly away with a number of worker bees to form a new colony or swarm.

Bees are not considered aggressive during swarming but caution still needs to be exercised around a swarm.

Swarms may be present for as little as 15 minutes or as long as three days. Usually, the swarm will move on to another site.

The European wasp (vespula germanica) arrived first in Tasmania before spreading to the mainland. It is an aggressive, scavenging pest that is most active in summer and autumn. Wasps deliver a painful sting that, unlike their bee relatives, can be used repeatedly to drive off would-be predators. European wasp colonies are concealed underground, in buildings or other out of sight places.

Paper wasps (polistes humilis) are about 10-15mm long with long thin wings. They make their nests of a grey papery material made from wood fibres. The nests are often found under an overhang such as a pergola or the eaves of a roof. Colonies generally range from 12-20 individual wasps. Paper wasps are foragers, bringing food such as chewed-up caterpillars back to the nest for their larvae. Paper wasps may attack if they feel threatened or if their nest is disturbed.

European wasp workers (sterile females) become active in warmer weather. Workers search for carbohydrate or protein food for their wasp grubs, including caterpillars, insects, carcasses or even picnic food. Adult wasps feed on meat juices, nectar and other sweet materials. Grubs may also be fed nectar.

The queen lays numerous eggs during spring and summer, one per cell. The eggs hatch into grubs which are fed until they enter the pupa stage. Then they emerge as adult workers that may only live for a few weeks. In late summer to autumn the workers build many larger cells in which queens and drones (males) are reared. These reproductives leave the nest to mate. The drones will die once they have fertilised the queen who will seek out a place to shelter over winter before starting a new nest site. Most queens will die due to predation, cold or unsuitable shelter.

Wasps can be treated by a qualified technician at any time of the day. When treating at night, it is important to use a red light as wasps may react aggressively to normal torchlight (we suggest using red cellophane over a torch if a red lamp is unavailable).

Ants are very common minded citizens of the insect world. They have kings, queens and immature stages back in the nest. The ones you usually find foraging through your kitchen, your garden and around your back door are the workers and maybe some soldiers. Some ants have painful stings but mainly they are pests because so many of them turn up uninvited at your home.

Winged males and females reproduce and leave a mature colony to set up on their own in a moist and secure crevice. They drop their wings and produce eggs which hatch into larvae and pupae that have to be tended and fed by the ‘royal’ couple. The young become sterile female adults or workers and they soon take over the operation, defence and extension of the nest and forage for food.

Later on, some species such as the Coastal Brown and Singapore Ants develop big headed soldiers or majors (also sterile females) that specialise in defending the colony. Argentine and Pharaoh ant colonies have many queens and millions of workers in an enormous conglomeration of interlocking nests.

Adults have elbowed antennae , a thorax and a globular abdomen with a sting on the tip. The eggs, larvae and pupae are usually white and immobile; often these can be seen being carried by workers to a new nesting site.

Of the thousands of different species of ants in Australia only a few are considered pests in and around our buildings. Individual size seems to be relevant to pest status. The large bull ants, trigger ants, sugar ants, meat ants and even the greenhead ants are of minor consequence if you’re not a keen gardener or you haven’t been stung. These ants seldom come inside buildings. It’s the small bland and brown ants (up to 5mm long) that develop large, hard to find colonies that are of the most concern.

They can undermine pavers and the root zones of plants, they can damage and short-circuit electrical components, enough to cause fires, and they can transfer viral, fungal and bacterial plant diseases while removing the sweet secretions from aphids, bugs and scale insects.

If it can possibly be considered to be food, there is a species of ant that will take whatever it is back to their nest. There’s a fairly loose generalisation that brown ants prefer protein and black ants prefer carbohydrates and that brown ants are more likely to nest in the building and blank ants outside. Just don’t count on it. It is also said that a surge in ant numbers and black ants moving their young and nest up into a building is a good indicator of rain. Don’t count on that either.

Although ants have comparatively powerful jaws and they do bite, the pain comes from the hypodermic sting or from venom sprayed from the tip of the abdomen over the bitten area. Large painful welts are almost instantaneous and allergic reactions have caused deaths.

Fleas are parasites belonging to the order Siphonaptera. Their mouthparts are specially adapted for piercing skin and sucking blood. They feed on warm blooded vertebrates such as cats, dogs, rodents, chickens and humans.

It is thought that fleas have claimed more victims than all the wars ever fought. The bubonic plague, which was spread by rat fleas, killed nearly 200,000,000 people. In other words, the entire population of Australia ten times over!

Fleas are wingless and cannot fly, but they are famous for being one of the longest jumpers in the animal kingdom. A flea can jump horizontally up to 33cm or 200 times its own body length.

Fleas can survive for several months without blood. When they do feed, they inject a small amount of anticoagulant into the puncture to aid in the siphoning of blood. Some people are allergic to flea saliva and may come out in a rash.

Female fleas will deposit four eggs after each feed, up to a hundred in their life cycle of a few months. The eggs may hatch within a week. The larvae feed on skin scales and undigested blood that is excreted by the adults. After four moults they spin a silken cocoon and may stay there in a dormant state for several months if conditions are unfavourable. Their emergence is often triggered by vibrations that may indicate that humans or pets have entered the area.

The main flea species that can attack humans are the cat flea, dog flea and the human flea. The latter two are rare, however the common cat flea is also found on dogs. Although uncommon, the only flea-borne disease in Australia is murine typhus, which is transmitted by rat fleas.

In all cases, pets must be treated by their owners before further flea treatments can be carried out. All bedding, kennels and other infested areas should be treated at the same time. Bedding can be washed or burned.

Prior to your flea treatment, we recommend that you vacuum the interior and leave the bag out for us to treat. The treatment includes internal areas and external areas. If rat fleas are suspected, then the treatment should coincide with a rodent treatment to eliminate the source of the fleas.

Rodents contaminate more food than they eat and in so doing, they transmit many diseases. In conjunction with the flea, rats were responsible for the deaths of 200 million Europeans from bubonic plague.

The three major pest species are the Norway Rat, the Roof Rat and the House Mouse. They are common in the major population centres of Australia and most countries of the world. As climatic conditions become less favourable during the onset of winter, rodents move indoors for both shelter and food. In commercial premises, rodents can be a year-round problem and mice can attain plague proportions especially in rural areas.

Rodents make their nests of soft materials such as shredded paper or fabrics, close to areas where they scavenge for food and water. Females are capable of giving birth to 4-6 litters a year, each litter containing 5-10 young, which are themselves capable of reproduction three months after birth. Within a year, the progeny of a single pair of rodents can number 400-700.

Rodents actively forage for food at night using the same route to and from the food source. Their diet includes food material of both plant and animal origin and water is a necessity especially for rats. Mice can obtain enough water from food provided it’s moist.

Although the vision of rodents is poor, their senses of smell and taste are so highly developed they can detect minute quantities of chemicals in foodstuffs which can lead to ‘bait shyness’. Their whiskers and guard hairs enable them to feel their way in their preferred darkness with little difficulty.

In Australia there are around 400 species of mosquito but only approximately 10 are commonly abundant and represent a serious pest threat because of their nuisance biting or their ability to transmit disease. Mosquitoes lay their eggs in stagnant water source such as wetlands, both natural and constructed, rain water tanks, pot plant saucers, plants that hold pools of water, hollows in trees, gutters and other items that may be left around that retain water.

The eggs can hatch within a few days and the larval stage begins. Mosquito larvae are aquatic and must live in a water source to survive and complete their development stage. Once the adult female emerges it will seek out a carbohydrate meal to replenish its energy. The female mosquito will mate with a male generally not far from the breeding site. For development of the eggs the female will need a high protein meal and this may be obtained from a source such as blood.

Batches of eggs can vary from 20 to 30 to several hundred depending on the species. Many mosquito species typically move only relatively small distances (sometimes no more than 50-100 metres) from their larval habitats provided appropriate blood sources are in the vicinity. However there is one species able to disperse up to 50 kilometers.

Several important human diseases are transmitted throughout Australia by these insects including Dengue fever, Australian encephalitis, Ross River virus disease and Barmah Forrest virus disease. Malaria has been transmitted locally in Australia but only rarely in recent decades.

In addition to being disease vectors, mosquitoes can cause major disruptions to occupational, recreational and social activities through their persistent biting.

Successful management of this pest depends on a variety of factors including familiarity with mosquito biology and identification. Identification of breeding sites is important to be able to treat mosquitoes in their larval stages in conjunction with an adult mosquito management plan that may involve treating harbourages such as vegetation and exterior walls of a property with a repellent product.

Simple measures can be taken by individuals to limit their contact with mosquitoes. Areas that are known to be infested with large numbers of mosquitoes should be avoided. Activities that are scheduled for outdoors, especially around dusk, should be limited as the biting activity of many mosquitoes will peak during this period. Clothing that has long sleeves and long pants should be worn when visiting areas that are infested with mosquitoes. A repellent that contains approx. 20% DEET (diethyl toluamide) should be used on exposed areas of skin but not repeatedly on young children. Windows and doors should be screened and water tanks covered with a small gauge mesh to exclude mosquitoes from these potential breeding sites. Empty all containers throughout the garden that hold water such as pot plant saucers, tyres, roof guttering and tins to prevent breeding.