SPECIES OF SPIDERS
Spiders can be divided into two main groups. These are:
• Webbing spiders and
• Crawling spiders
As the name suggests, these spiders build and live in webs and use this to catch their prey. Mature spiders, when moving in search of food, produce a strand of silk which is carried by the wind until it comes into contact with a building or other stationary object. The spider then travels across this strand of silk and proceeds to build a new web.
Most common household spiders spin their webs over lamps, in curtains, railings, around windows and gutters. Under some conditions, spiders are considered beneficial because they feed on insects. However the unsightly webs used to catch the insects usually outweigh the beneficial aspect.
Management of webbing spiders can include physical measures like trying to eliminate or reduce the food supply (insects) in the infested area e.g. turning off external lights at night. Temporary measures can include the physical removal of webs, however this will not eliminate the spider population.
Most effective chemical management involves sprays that target the spider directly. Chemical on the webs is not always effective since most webbing spiders hang on using claw-like structures which do not readily absorb chemical residues. However, it is recommended that webs do not be removed for a couple of weeks after spraying.
Red-back spider – Latrodectus hasselti
Redbacks are considered a nightmare to most of us in Brisbane, but particularly to those who have young children, with their inquisitive minds and fingers, poking and prodding into those places which this spider inhabits.
• The female Redback spider has a venom which is toxic to humans, with bites causing severe pain and even possible death.
• The female Redback has a round body about the size of a large pea (1 cm long), with long, slender legs.
• The body is a deep black colour (occasionally brownish), often containing an obvious orange to red longitudinal stripe on the upper abdomen.
• Webs are usually built in dry, sheltered sites, such as among rocks, in logs, shrubs, old tyres, sheds, outhouses, children’s toys or under rubbish or litter.
Crawling or hunting spiders
These spiders do not live on webs but instead are nomadic, making their home under leaf litter or bark, in hollows or purpose built burrows and in general garden areas. Unlike webbing spiders, they hunt down their prey or lie in wait to ambush their prey.
Although they may be looking for potential prey, these spiders will often find their way into your home during the warmer months to escape the summer heat. Squeezing into gaps under doors and windows is natural behaviour and once inside they will gladly make your house into their home.
It is quite difficult to target huntsman with a treatment. However, as they are hanging around your home looking for potential prey, a general pest treatment to the outside of the house to eliminate insects and web-building spiders, will make your house less attractive to these huntsman.
Control of crawling/hunting spiders inside of the home is often limited to removal or elimination of each individual spider. Unless the species is considered dangerous, the best method of dealing with these spiders is to move them back into their habitat.
Keeping the perimeter of your home clear of vegetation and garden beds, and ensuring your insect screens are in good order and well fitting, will also help.
• Frequently very large
• Will bite if provoked but are not deadly to humans.
• Legs are crablike and covered in fairly prominent spines.
• Colour is mainly dull shades of brown or grey.
• Live in crevices of tree bark. Frequent sheds and garages and other infrequently used places.
• Are able to travel extremely fast, often using a springing jump while running, and walk on walls and even on ceilings.
• Tend to exhibit a “cling” reflex if picked up, making them difficult to shake off and much more likely to bite.
• Eat insects – (cockroaches are a favourite) and even small geckos.
• Hunt, rather than spinning a web to capture prey.
• Preferred prey is spiders and they are equipped with venom for hunting.
• Adult size varies 12 to 20 mm in body length
• Grey to black in colour with a white section on the end of it’s tail.
• Prefers cool moist locations – commonly found in garden mulch areas.
• In summer, it often wanders into buildings, particularly bathrooms, to escape the heat.
• It’s bite may cause nausea and burning pain followed by swelling and itchiness around the site of the bite.
Black House Spider – Badumna insignis
• A dark robust spider, with the female being larger than the male.
• Carapace and legs are dark brown to black, and the abdomen is charcoal grey with a dorsal pattern of white markings (sometimes indistinct).
• Webs form untidy, lacy silk sheets with funnel-like entrances.
• Found on tree trunks, logs, rock walls and buildings (in window frames, wall crevices, etc).