Spiders

Most spiders are more of a nuisance than a pest, but they do keep insect numbers down. of the spiders found in and around the Queensland homes and buildings, only the redback spider is considered an important pest. While there are other dangerous spiders in Queensland, they are not considered very serious.

Appearance and habits.

Grey House Spider
The Grey House Spider is commonly found in Queensland houses. They do not cause any trouble apart from forming unsightly webs, particularly in the corners.

This small spider is 8mm to 9mm long, roughly spherical with long thin brown legs. Down the middle of their backs are a burnt orange stripe or patch.

The adult female sits upside down in her web, which consists of a loose, untidy tangle of sticky threads. The female will drop immediately to the ground when disturbed. Although it sometimes mistake for the redback spider, the bite of the grey house spider is not harmful.

White-kneed Spider
The white-kneed is also a common spider in the house. They do not cause any problems except to be unsightly.

It is 1.5cm long. The abdomen is black grey with white patches below the joints, particularly on it's fore legs.

The webs is wheeled shaped with an oval patch of silk in the middle, where the spider rest in the regular characteristics pose.

It is non-venomous, using large amounts of silk to overcome its prey.

Daddy-Long-Legs Spider
The daddy long legs belongs to the family pholcidae of which the species pholcus phalangioides is most commonly found in Queensland homes.

These spiders have a small body and long thin thread-like legs. The female of the common species is 7 to 8mm in body length with its legs up to 50mm long.

The web is a tangle of irregular soft strands which looks like a rough horizontal sheet about 25cm across.

The spider hangs up side down within the nest, and remains there at all times. it is usually found in dark places, such as behind doors and in garages, sheds, boxes, closed rooms and under stairs.

Redback Spider
The red back spider is wide spread in Australia, and other countries. In New Zealand it is known as the Katipo, and in America it is known as the Black Widow. They are known for the poisonous bite.

The female is 8 - 14mm with the front part of her body much smaller than the large pea shaped abdomen. Their legs are long and thin

The body is usually dark, almost, black with a bright cherry-red stripe down the back of it's abdomen and a hour-glassed shape on its underside.

The male is much smaller than the female, and is rarely seen.

The upper area of the web, where the adult sits, is connected to a lower are of the web where the prey is snared . Webs are built in cool, dry shady areas with a minimal chance of disturbance such as around houses, farm sheds, factories, machinery. Although it likes to nest across open areas it will nest in wood piles, rockeries, logs and the bush toilets.

Life Cycles

Grey house spider
The female lays a lot of eggs which are then covered with silk to form small paper brown egg sacks. the female may produce 1 or 2 egg sacks.

The young, or spider lings, hatch in large numbers and through the a number of moults, reach sexual maturity in nine months. There is usually one generation each year.

White-kneed spider
The eggs laid by the adult female are covered silk to form a white, flattened, star shaped egg sack. There maybe several egg sack in the web.

The young hatch into spiderlings that go through a series of moults to reach the adult stage. Like the grey house spider, there is usually, only one generation per year.

Daddy-Long-Legs Spiders
The female carries the eggs, which are loosely woven together. The young spiderlings pass through a series of moults until reaching adult stage, usually in summer. there is normally only one generation per year.

Redback Spiders
The female lays her eggs and covers them with silk to form a pale brown spherical egg sack. these sacks are hung in the upper part of the web. Each female producers 3 to 4 egg sacks and each may contain up to 300 eggs.

The potentially high spider population is limited by a small parasite wasp, and by cannibalism. The surviving spiderlings float away on gossamer threads to set up homes of their own. Heavy rains and the attack from birds further depletes the populations.

The spider mature in early summer, and lay their eggs in mid to late summer and then hatch in autumn, and there appears to be only one generation per year.

Control

Regular inspection and destruction of spiders and their webs is a cheap and effective way to keep building reasonably free of spiders.

Chemical Control
When applying insecticides, the spray should be directed at the spider. Their habits of sitting in the middle of their web with out coming in contact with the surface of a wall and such, make residual sprays less effective.

Special advice on Redback Spiders.

Redbacks are not aggressive spiders, they rarely leave their nest. It is only when a hand or another part of the body disturbs the nest that they will bite. Fatalities are rare. Since the introduction of the antivenin no deaths have been recorded.

Symptoms of a bite
A light sting is felt when a redback bite. This is followed by immediate itching, and then the gradual onset of possible severe pain. After 20 to 30 mins the body temperature rises and nausea and vomiting occurs. Profuse sweating, as well as inflammation and swelling of near by lymph glands with the progressive muscular weakness are also symptoms.

First Aid

• Keep all movement to a minimum.
• Wash the wound
• Do not apply tourniquet
• Take victim to nearest hospital immediately