Funnel weaver spiders get their name from the funnel-shaped webs they weave. In North America and Europe, funnel spiders do not cause medically significant bites. In Australia, three genera of funnel-web spiders (the Hadronyche, Illawarra, and the Atrax) are potentially life-threatening. However, at most, only 15% of their bites are venomous.
One look at the difference between spiders outside Australia versus those inside tells you why. Funnel weaver spiders in North America and Europe are aranemorphs (modern spiders). Funnel-web spiders in Australia are mygalomorph (primitive spiders).
Aranemorph spiders have fangs that move from side to side and cut like scissors to deliver venom to help digest their prey. Mygalomorph spiders have fangs that point down like a spider and give a poison meant to paralysis and kill their prey.
Tarantulas and trap door spiders are examples of mygalomorphs living in the United States. Another interesting fact about mygalomorphs is their life spans, with some species living for decades.
Related: How to identify the Black widow spider.
Related: How to identify the Brazilian wander spider.
Funnel weaver spiders in North America.
The webs of funnel weaver spiders are frequently seen on mown lawns after an early morning dew. Indeed, the members of the Genus Agelenopsis are so numerous and familiar as to be called “Grass Spiders.”
Of the 1,200 species of funnel weaver spiders, about 100 of them live in North America.
While funnel weaver spiders are nocturnal, they can easily be observed by slowly approaching the web during the day and looking down the throat of the funnel. As long as you don’t let your shadow cross over the entrance, you should be able to spot the tiny brown spider with stripes running along its length.
Like the Hobo spider, funnel weaver spiders have conspicuous spinnerets protruding from their rear. In most spiders, these silk-spinning appendages are found on the bottom of the spider’s abdomen and are harder to spot.
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Barn funnel weaver spiders.
Barn funnel weaver spiders (Tegenaria domestica) build their webs in barns, sheds, and basements. These spiders range from 1/4 to 1/2 inch in size and are tan or light brown, with a pair of darkish lines starting at the eyes and running down their body.
Of all the funnel weaver spiders, the spinnerets of the barn funnel weaver spider are tiny in comparison and much harder to see.
Funnel weaver spiders in Europe.
Of the funnel weaver spiders in Europe, the Agelena labyrinthica is one of the most widespread species and interesting.
Labyrinth spiders create thick, white sheet webs along south-facing vegetation. These webs can be from ground level to five feet above the ground. At one end of the web is the funnel, or the “retreat,” where the funnel web spider conceals itself.
Deep down inside the funnel is a labyrinth of additional tunnels built not to trap prey but to prevent predators from discovering the egg sac holding young, developing spiderlings.
Agelena labyrinthica is larger than the funnel weaver spiders found in North America (growing as large as 3/4 inch, and has more elongated spinnerets. Its venom glands are also larger, extending from the mouth to the middle of the abdomen.
Avoiding funnel weaver spiders.
If you keep your yard and home’s exterior tidy, you’ll likely never have a problem, much less an infestation of funnel web spiders. The funnel webs on your lawn are excellent insect control.
If you want to avoid encountering a funnel weaver spider, keep your basement, garage, and sheds dry and clean.
Around the exterior of your home (on siding, under eaves, deck rails, and near exterior lights that draw other flying insects, use a spider deterrent.
The Sydney funnel-web spider (Atrax robustus) is a venomous spider native to eastern Australia, usually found within a 50-mile radius of Sydney. It is a member of a group of 40 species of funnel-web spiders known as Australian funnel-web spiders. Its bite is capable of causing severe illness or death in humans if left untreated.
The Sydney funnel-web has a body size ranging from 1/2 to 2 inches in length. These spiders are glossy and darkly colored, ranging from bluish-black, black, brown, or plum-colored hues.
Sydney funnel-web spider bites.
The Sydney funnel-web spider will let you know when threatened or provoked by rearing up on its back legs and displaying its fangs. If it must defend itself by biting, the Sydney funnel-web spider will retain a grip on you and keep biting.
Since 1981 antivenom has been available to treat victims, but treatment must be immediately sought as envenomation can begin within 30 minutes. In addition, small children suspected of being bitten must receive immediate medical treatment as death can occur within 15 minutes without it.
Symptoms of Sydney funnel-web envenomation include: “Facial paresthesias, nausea, vomiting, profuse diaphoresis, drooling, and shortness of breath. In addition, patients may become agitated, confused, and ultimately comatose.
“This is associated with hypertension, metabolic acidosis, dilated pupils, muscle twitching, and pulmonary and cerebral edema. Death results from pulmonary edema or progression to hypotension and circulatory collapse.”
Sydney funnel-web spider habitat.
Like most funnel-web spiders, the Atrax robustus prefers moist forest areas of the Hornsby Plateau to the north and the Woronora Plateau to the south. Here it will shelter in burrows within gardens and bushlands.
There is an interesting real estate-based guide on the population densities of Sydney funnel-web spiders that goes something like this, “the more expensive the area, the greater the funnel-web population.”
Avoiding funnel-web spiders.
The burrows of funnel-web spiders can be found in cool, moist, and sheltered locations like under rotting logs, dense shrubs, heaped stone arrangements, leaf piles (seen below), and gardens.
After heavy rains, flooded-out funnel-web spiders will be active and found roaming around even during the day, especially at night. While gardeners always have to be alert for the presence of funnel-web spiders, the drier the conditions, the less likely a funnel-web spider will be active during the day.
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How funnel-web spiders catch their prey.
The silk opening of a Sydney Funnel-web spider burrow has a somewhat funnel-like entrance ‘vestibule’ containing a collapsed, tunnel-like structure with one or two slit-like openings.
The tunnel leads back into a short surface chamber from which the burrow descends. The shelter is only slightly lined with silk and less than a foot deep.
The funnel-web spider hunts by sitting at night with its front legs resting on silk trip-lines. If an insect walks across one of these lines, the funnel-web spider darts out grips it, and drags it deep into the funnel.
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