The Sydney Funnel-web Spider
Funnel-web spiders are found in eastern Australia, including Tasmania, in coastal and highland forest regions - as far west as the Gulf Ranges area of South Australia. Thirty-six species, including three tree dwelling species, have been identified.
Habitat and Distribution
Funnel-webs burrow in moist, cool, sheltered habitats - under rocks, in and under rotting logs, crevices, rot and borer holes in rough-barked trees. In gardens, they prefer rockeries and dense shrubberies, and are rarely found in more open situations like lawns. The most characteristic sign of a Funnel-web's burrow is the irregular silk trip-lines that radiate out from the burrow entrance of most species. These trip-lines alert the spider to possible prey, mates or danger. Rain may flood burrows and the temporary retreats of male Funnel-webs, causing an increase in their activity. Funnel-webs are very vulnerable to drying out, so high humidity is more favorable to activity outside the burrow than dry conditions. Most activity is nocturnal. Gardeners and people digging in soil may encounter Funnel-webs in burrows at any time of the year.
The Sydney Funnel-web Spider
The Sydney Funnel-web Spider (Atrax robustus) occurs from Newcastle to
Nowra and west to Lithgow. They especially favor the forested upland areas
surrounding the lower, more open country of the central Cumberland Basin. This
includes the Hornsby Plateau to the north, the foothills of the Blue Mountains
to the west, and the Woronora Plateau to the south. Funnel-web occurrence is low
in much of central-western Sydney, and also the sandy coastal parts of the
eastern suburbs and the Botany Bay area. They do better in areas of sandy clay,
shale or basaltic soils that can retain moisture more effectively.
Identification
Funnel-webs are large spiders (1.5 - 4.5 cm body length) with glossy dark brown to black carapace. The abdomen is usually dark plum to black and not patterned. Males often have a ventral spur or swelling midway along the second leg, which is pointed in Atrax and blunt (when present) in Hadronyche. Spinnerets usually obvious, finger-like and at the end of the abdomen. The eyes of Funnel-webs are closely grouped. Spiders commonly mistaken for Funnel-webs include: Trapdoor Spider and Mouse Spider
Habits, Mating and Reproduction
Female Funnel-web Spiders spend most of their life in their burrows, but do occasionally hunt on the surface at night. Adult males however leave their burrows and wander in search of females, particularly during summer and autumn. This is when most encounters with humans occur, with males accidentally wandering into houses and garages, often via gaps under doors. The males spend their entire short adulthood seeking as many receptive females to mate with as possible. Male Funnel-webs approach the females' hidden burrows, possibly by following the scent of their chemical attractants. During mating, the male must restrain the female from striking him with her fangs using the spurs on his second legs, while he transfers sperm via his pulps into her genital opening. The female then spins a pillow-shaped silk egg sac, into which she lays over 100 eggs. She cleans and turns the egg sac several times during incubation and will defend it vigorously if disturbed. The spider lings hatch about three weeks later, and stay with the mother for a few months. After two moults, they leave her burrow, dispersing by foot to eventually make their own burrows. Juvenile males will stay in their burrows until their final adult moult, after which they will become wanderers. Funnel webs mature in about two to four years, with the females living to ten or more years, and the males dying about six to nine months after maturity.
Toxicity
Bites are most prevalent during summer and autumn when males leave the burrows in search of females. Accidental encounters with wandering males usually occur in gardens, houses, garages and sheds - particularly ground-level dwellings on concrete slabs. Bites are dangerous and can cause serious illness or death. The venom appears to particularly affect primates (ie humans), whereas other mammals - such as cats and dogs - are relatively resistant. The male Sydney Funnel-web Spider is more dangerous than the female. This is because the toxic venom component that attacks the human and primate nervous symptom so severely is only present in male spiders. Initial symptoms after a bite include local pain, mouth numbness, vomiting, abdominal pain, sweating and salivation. Ant venom is available and no deaths have occurred since its introduction.
FEMALE MALE
WHITE TAIL SPIDER
Adult body length:
20 mm (female), 12 mm (male)
Web-
Does not build a web.
Color-
Female: body dark gray, legs with reddish brown tinge, abdomen with dull white patch at tip and sometimes with more or less distinct, paired, pale spots on the middle of the abdomen.Male: Similar to female but with two pairs of pale spots always present on the abdomen and a dark, oval plate toward front of abdomen on upper side.
Form-
Body cylindrical, often described as cigar-shaped, front two pairs of legs directed forward.
Bites-
Bites by this spider are relatively frequent due to its wandering habit. Symptoms range from no reaction to swelling and local blistering at the bite site and nausea. The white tailed spider has been suggested as a culprit in rare cases of large scale necrotic lesions but there is little supporting evidence.
