What Do Sydney Funnel Web Spiders Eat?

Funnel-Web Spiders: Families, Bites & Other Facts

Funnel-web spiders are spiders that build funnel-shaped webs, which they use as burrows or to trap prey. Three distinct spider families are known popularly as funnel-web spiders, but they are all quite different. Some species are among the most deadly spiders in the world, while others are not harmful to humans.

These spiders get their name because, generally, their webs have a flat surface for capturing prey and a small funnel-like tube leading to a silken burrow in which the spider hides, according to the University of California’s Integrated Pest Management Program (IPM). The spider waits in the funnel for prey to fall onto the horizontal web, and then it rushes out, grabs the prey, and takes it back to the funnel to consume.

Taxonomy/classification

According to the Integrated Taxonomic Information System (ITIS), the taxonomy of spiders is:

  • Kingdom: Animalia
  • Subkingdom: Bilateria
  • Infrakingdom: Protostomia
  • Superphylum: Ecdysozoa
  • Phylum: Arthropoda
  • Subphylum: Chelicerata
  • Class: Arachnida
  • Order: Araneae
  • Families: There are more than 100 families of spiders. Three are known popularly as funnel-web spiders: Agelenidae, Dipluridae and Hexathelidae.

A funnel weaver lies in wait deep within her funnel. (Image credit: PHOTO FUN Shutterstock)

Agelenidae: Non-dangerous funnel spiders

Agelenidae spiders, also called funnel weavers, live throughout the world. According to the Encyclopedia of Life(EOL), there are nearly 1,200 species of agelenids worldwide; about 100 of them are found in North America. “This family includes the grass spiders [genus Agelenopsis],” said entomologist Christy Bills, invertebrate collections manager at the Natural History Museum of Utah. Other genera of funnel weavers include Tegenaria (barn funnel weavers) and Eratigena (hobo spider), which are native to Europe.

Agelenid spiders build funnel-shaped webs between two braces, such as branches or grass blades. In general, their bites are not harmful to humans. One possible exception is the hobo spider. According to the EOL, this species has gained a reputation for being dangerous to humans, but several studies have found little evidence to support the claim.

Appearance

Agelenids are medium-sized for arachnids — about 4 to 20 millimeters long (up to three-quarters of an inch). According to the University of Michigan’s BioKids, these species are usually grey or brown, with spots on their backs and banded legs. “They have eight eyes,” Bills said, arranged in two rows.

Behavior

Like most species of spiders, funnel weavers are nocturnal. They are known to flee from light and “many are very fast runners,” Bills said.

According to BioKids, they typically live for less than a year, dying in the cold weather. In warmer places, they can live for two years. Males spend most of their time wandering in search of a mate, though they usually die after they mate a few times. Females rarely leave their webs. They typically lay several egg sacs and cover them in webbing for protection. Agelenids lay eggs in the fall, and the spiderlings hatch in the spring. Dead female spiders are often found clinging to the egg sac, according to Herbert Levi and his co-authors in «Spiders and Their Kin» (St. Martin’s Press, 2001).

Web

Residents of grassy areas will recognize the funnel webs scattered in the grass during the summer and early fall. According to Iowa State University’s BugGuide.net, webs are also often seen in the corners of porches or in the cracks of shingles (anywhere there is a crevice for them to build a funnel web inside).

These spiders typically eat insects, though they have been known to eat other spiders.

Hexathelidae: Dangerous Australian funnel spiders

Hexathelid spiders live in Australia, and their funnel webs are really burrows lined with silk. These spiders have a dangerous bite. Two well-known species of Hexathelidae are the Sydney funnel spider and the northern tree funnel spider. Both are often included on lists of the most deadly spiders in the world, according to the Commonwealth Scientific and Industrial Research Organization (CSIRO).

“This group contains some spiders of medical significance in their native Australia,” Bills said.While most species are not dangerous to humans, the Sydney funnel spider and the tree-dwelling venomous biters have garnered deadly reputations.

Appearance

According to the World Heritage Encyclopedia, these funnel spiders are medium-sized, getting up to about 1 to 2 inches (2.54 to 5 centimeters), and are typically black or brown. Bills noted that they are mygalomorphs, which means they have “distinct fangs and . long spinnerets.” They are distinguished by their shiny carapace (hard covering over the front of the body), which is lightly haired. Males are smaller than females.

Behavior

According to Bills, these spiders typically live in burrows. These mostly nocturnal spiders can be found at any time of the year. They prefer humid climates, as they are susceptible to drying out, according to the Australian Museum.

During the summer, males leave their burrows and go wandering for females. The two spiders spar until the female accepts the male. To mate, they rear up on their hind legs and press their bodies together, according to the Australian Museum. They also assume this rearing position when threatened.

According to the Queensland Museum, the female spider lays her eggs in her burrow. Once they hatch, the young spiders stay in the burrow until they are big enough to leave. Males only live for a few months after mating, but females can live for several years (some reports say up to 20).

Burrowers

Australian funnel spiders pick moist and sheltered places to build their burrows, like under rocks or logs or in shrubbery. According to the Museum Victoria, the entrance to the burrow is surrounded by irregular strands of silk, which act as trip wires, alerting the spider hiding in the burrow that prey is present. The spider then goes out and attacks.

These spiders usually eat insects or small vertebrates like lizards or frogs.

Tree dwellers

While most funnel spiders live on the ground, a few species on the eastern coast of Australia live in wet forest trees. They typically live in rotting holes in the bark and build silk trip wires outside the holes to alert themselves to prey, according to the Australian Museum. The inside of their holes may be lined with silk, and bits of bark are used to disguise the entrance. Their dwellings have been found as much as 30 meters off the ground.

Dangerous species

According to the Australian Museum, bites from all species of Australian funnel-web spiders are considered potentially dangerous, but the two most notorious are the Sydney funnel-web spider and the northern tree-dwelling funnel spider.

The black or brown Sydney funnel-web spider’s habitat correlates closely with the greater Sydney area. Male Sydney funnel-webs are exclusively responsible for human deaths from this spider’s bite. Their venom is five times as toxic as the female’s because it contains a special chemical called Robustoxin. Females lack this chemical, explains the Australian Museum. Furthermore, males wander, searching for mates and running a higher risk of encountering humans, while females stay in their burrows.

See also:  10 Biggest Spiders In The World

The northern tree-dwelling funnel spider is also highly dangerous but much more rarely encountered because it lives in a remote mountain area.

Antivenom was discovered in the 1980s, and no one has died of bites from either species since.

Dipluridae: Funnel-web tarantulas

Spiders in the Dipluridae family are commonly known as funnel-web tarantulas. “This family belongs to the group of mygalomorphs, a spider group with distinct fangs and they have long spinnerets,” Bills said.

Most of these spiders live in the tropics of Central and South America, but they are found worldwide, including Australia, Africa and Central Asia.

Appearance

These spiders are medium to small-size, according to the World Heritage Encyclopedia. Some are as small as 3 mm, while others grow to about 15 mm (about half an inch).

Behavior

Their funnel webs are rather messy and are composed of flattened, often branching tunnels they can use for retreating when danger approaches. Some species prefer to hide their webs under rocks, while others live exclusively under mats of moss, rotting logs and other organic debris, according to the EOL.

Additional resources

  • Iowa State University’s Bug Guide: Funnel Weavers
  • Australian Museum: Sydney funnel-web spider
  • BioKIDS: Agelenidae

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Funnel Web Spider The World’s Deadliest Spider

There are 35 species of funnel web spider distributed alone the eastern seaboard of Australia but only 6 of these are dangerous. The deadliest, of course is the Sydney funnel web spider that is found in the vicinity of the city of Sydney.

The Sydney funnel web spider (Atrax robustus) is the deadliest spider in the world. Its venom, if untreated can kill a human in as little as 15 minutes. Interestingly, this spiders venom is only fatal to primates such as humans. Cats and dogs don’t seem to suffer the same consequences.

The Sydney funnel web spider is a large aggressive spider with prominent and menacing fangs. If threatened it will rear up, display its prominent fangs and stand its ground and attack if necessary.

They have body lengths of 35mm for the females and 25mm for males. Being an arachnid its body consists of two parts. The front part referred to as the cephalothorax contains eight tiny eyes, brain, mouth consisting of a tube similar to a feeding straw, its chelicerae which are pincers with inbuilt fangs, pedipalps which are a set of arms for holding prey, venom glands, a sucking stomach and all of its eight long legs. (See diagram). The cephalothorax is a glossy black in colour. The second part of its body is its abdomen, located immediately behind the cephalothorax and joined to it by a thin flexible waist called a pedicel. This acts like a joint, allowing the spider to move its abdomen without moving its cephalothorax. The abdomen contains its lungs, heart, intestine, reproductive organs, silk glands and spinnerets from which it produces its silk. The abdomen is usually black or dark purple in colour.

The funnel web spider builds a funnel-shaped web (hence its name the «funnel web») with fine strands of silk web treads extending from the entrance into the surrounding area. These thread act as tripwires. The moment an unwitting insect trips on of these threads the funnel web spider. Lurking within its burrow leaps out and stings its prey, paralysing it, and drags it into its lair to be consumed. The spiders diet usually consists of as all sorts of crawling insects such has beetles, cockroaches, snails and also small animals such as lizards.

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Funnel-web Spiders

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Funnel-web spiders, the most notorious members of our spider fauna, are found in eastern Australia.

There are at least 40 species of funnel-web spiders and they are currently placed in two genera: Hadronyche and Atrax. They are medium to large spiders, varying from 1 cm — 5 cm body length. Males are more lightly built than females. Body colour can vary from black to brown but the hard carapace covering the front part of the body is always sparsely haired and glossy. The lateral pair of spinning organs (spinnerets) at the end of the abdomen are longer and easily visible in Atrax spp. but often shorter in Hadronyche spp.

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Not all species are known to be dangerous, but several are renowned for their highly toxic and fast acting venom. The male of Atrax robustus, the Sydney Funnel-web Spider, is probably responsible for all recorded deaths (13) and many medically serious bites. This remarkable spider has become a part of Sydney’s folklore and, although no deaths have been recorded since the introduction of an antivenom in 1981, it remains an icon of fear and fascination for Sydneysiders.

Funnel-web Spider, Atrax robustus, close up using Scanning Electron Microscopy (SEM).

Image: Sue Lindsay
© Australian Museum

Identifying Funnel-web Spiders

  • Shiny carapace
  • Deeply curved groove (fovea)
  • No obvious body pattern
  • Eyes closely grouped
  • Four spinnerets, largest with last segment longer than wide
  • Lower lip (labium) studded with short, blunt spines
  • Modified male second leg (usually with a mating spur or grouped spines)
  • An obvious, conical projection or ‘spur’ on the lower side of the middle segment (tibia) of the second leg (about halfway along) is characteristic of the genus Atrax, exemplified by the Sydney Funnel-web Spider, Atrax robustus. Males of all other funnel-web species (currently placed in the genus Hadronyche) either have a blunt, spine-covered tibial swelling, or a few spines only, on the second leg. Note also the mating organ on the male palp.

This specimen of the notorious Sydney Funnel-web Spider was responsible for the first recorded human death by this species. On 5 February 1927, a toddler sitting on the laundry steps of a house in Thornleigh was bitten on the little finger. It is suspected that the child tried to crush the spider in his hand, which is why the specimen is somewhat squashed. Funnel-web spiders grow up to 3.5 cm in length. They live in cool and humid burrows beneath logs and rocks, across which they spin silken trip lines to alert them to the presence of prey. Although they are one of the most venomous species of spider in the world, there have been no fatalities from Sydney Funnel-web Spider bites since the introduction of antivenom.

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A male Sydney funnel-web spider, Atrax robustus.

This funnel-web spider (Hadronyche sp) was brought into the Australian Museum to be identified. On closer inspection it was found to be infested with phoretic mites (the small brown dots covering the thorax (head)). Phoresy is where an animal attaches to another for transportation only.

Suspects gallery

These spiders are funnel-webs:

  • Sydney Funnel-web Spider (Atrax robustus) male
  • Southern Tree Funnel-web Spider (Hadronyche cerberea)

These spiders are sometimes mistaken for funnel-webs:

  • Sydney Brown Trapdoor Spider (Misgolas rapax) male
  • Sydney Brown Trapdoor Spider (Misgolas rapax) female
  • Mouse Spider (Missulena sp) female
  • Bymaniella near Guyra, New South Wales
  • Black house spider (Badumna insignis)

Where Funnel-web spiders live

Funnel-web spiders live in the moist forest regions of the east coast and highlands of Australia from Tasmania to north Queensland. They are also found in the drier open forests of the Western Slopes of the Great Dividing Range and South Australia’s Gulf ranges. Funnel-webs of the genus Atrax have a much smaller distribution than do the more diverse members of the genus Hadronyche. The Sydney Funnel-web Spider, Atrax robustus, is found from Newcastle to Nowra and west as far as Lithgow in New South Wales.

In Sydney suburbia, funnel-web spiders mostly live in the moist upland forest areas of the Hornsby Plateau to the north and the Woronora Plateau to the south, where sheltered burrow habitats abound in both bushland and gardens. The dry, flatter areas of western Sydney and the Cumberland Plain have fewer funnel-webs, their numbers picking up again in the foothills of the Blue Mountains. Two funnel-web species are common in the Sydney region — the Sydney Funnel-web Spider (Atrax robustus) and the Southern Tree-dwelling Funnel-web Spider (Hadronyche cerberea).

While Sydney Funnel-webs were never restricted to the leafy north shore region as some would have it, Sydney real estate does give a rough guide to funnel-web density — the more expensive the area the greater the funnel-web population (the dry, sandy eastern suburbs excepted).

Within Hadronyche several groups of related species are currently recognised. These species groups are:

  • cerberea group, found entirely south of the Hunter River into Tasmania, except for a single species, the Northern Tree-dwelling Funnel-web Spider, H. formidabilis, the largest funnel-web spider (body length up to 5 cm)
  • infensa group, found north of the Hunter River region into south-east Queensland
  • adelaidensis group, isolated in the dry forests of the Gulf Ranges of South Australia; the only trap-door building funnel-web spider
  • a single species isolated in the wet forests of the Illawarra region of New South Wales
  • ‘lamington’ group, several species confined to discrete rainforest areas in New South Wales and Queensland
  • anzes group, a single, far northern outlier species in rainforests north of Cairns, north Queensland.

Sheltered retreats

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 favourable 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.

Blue Mountains Funnel-web spider burrow entrance (Hadronyche versuta), clearly showing silk triplines radiating out from entrance.

Image: Ramon Mascord
© Ramon Mascord

Early warning system

Funnel-web burrows are distinguished from other holes in the ground by the presence of a series of irregular silk ‘trip-lines’ radiating out from the entrance. If a spider burrow has obvious silk trip-lines around its rim you can be fairly certain that it belongs to a funnel-web spider.

The silk entrance to the burrow of a Sydney Funnel-web Spider has a more or less well-defined funnel-like silk entrance ‘vestibule’ within which is 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 burrow is often weakly silk-lined and rarely more than 30 cm deep. The spider (hunting mostly at night) sits just inside the entrance with its front legs on the trip-lines. When a beetle, cockroach, or small skink, typical items of funnel web food, walks across the lines, the spider senses the vibrations and races out to grab its meal. The prey is quickly subdued by an injection of venom from the spider’s large fangs. Funnel-web spiders may also forage on the surface in the vicinity of the burrow.

Holes are normally found in moist, shaded areas like rockeries, dense shrubs, logs and leaf litter. A small, neat hole lined with a collar of silk which does not extend more than a centimetre from the rim could belong to a trapdoor spider (the common Brown Trapdoor Spider does not build a ‘door’ for its burrow). Other possible hole owners include mouse spiders, wolf spiders or insects (most commonly cicadas or ants).

The tree dwellers

Most funnel-webs are ground dwellers but a few live in trees. The largest of all funnel-webs is the Northern Tree Funnel-web Spider, Hadronyche formidabilis, reaching 4 cm — 5 cm body length. These spiders live in the wet forests of northern New South Wales and southern Queensland and have been found over 30 m above ground. While many have their retreats in surface-opening branch rot-holes, some spiders appear to live and feed entirely inside the deadwood pipe of large forest trees like Tallow-wood, feeding on beetles and other insects inside this rotting wood habitat. The smaller Southern Tree Funnel-web Spider, H. cerberea, is common in the Sydney and Central Coast regions, but ranges all over eastern New South Wales south of the Hunter River. The abdomen sometimes has a light plum colouration. They make silk-lined retreats in holes and rot-crevices in a variety of rough-barked trees, including Melaleuca (paperbarks), Banksia, Casuarina (she-oaks) and eucalypts. The exposed web surface tunnel is disguised by a covering of bark or wood particles. There are often two entrances, each with trip-lines running out across the bark. Prey ranging from beetles to tree frogs are taken by these spiders.

Southern Tree Funnel-web Spider

Image: Mike Gray
© Australian Museum

Wandering and mating

After they mature, male spiders leave their burrows and become wanderers, especially during the summer/autumn months, looking for females in their burrows. Chemicals called pheromones in the female’s tripline silk help the male locate and identify her burrow. Well before mating, the male spins a small silk sperm web, onto which he deposits a droplet of sperm from his abdominal genital pore. The sperm it is then taken up and stored in the mating organs at the ends of the male’s palps.

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The spur and/or spines on the male’s second legs are used to hold the female during mating. During mating, considerable sparring occurs until the female accepts the male. Both spiders rear up with first legs raised against each other, while the male engages his mating spurs across the bases of the female’s second legs. The male then inseminates the female by inserting the tips of his palpal organs into the female’s genital opening on the underside of her abdomen.

The male factor

Only male spiders have been responsible for all recorded funnel-web envenomation deaths — why is it so? The answer lies in a combination of spider behaviour, venom chemistry, and even colonial politics.

During the warmer months of the year (November-April) male funnel-webs wander about at night looking for females in their burrows. Males wandering in suburban gardens may sometimes become trapped inside houses or garages, especially those with concrete slab foundations where entry points under doors are easily reached.

The venom of the male Sydney Funnel-web Spider is very toxic. This is because male spider venom contains a unique component called Robustoxin (d-Atracotoxin-Ar1) that severely and similarly affects the nervous systems of humans and monkeys, but not of other mammals. The absence of this chemical from female Sydney Funnel-web Spider venom explains why bites by these females have not caused any deaths. However, not all funnel-web species show such a large gender-based difference in venom toxicity. Almost four million people live in the Sydney region, the centre of the distribution of the Sydney Funnel-web Spider. This makes the likelihood of human encounters with this spider much greater than in less urbanised areas like the Blue Mountains. This situation, of course, stems from a political decision made in London more than 220 years ago, to establish a colony in ‘New South Wales’ at Sydney Cove, a site nominated by Captain James Cook after his voyage of exploration.

Taken together, these ingredients produce a recipe for unexpected and potentially life-threatening encounters.

Funnel-web Spider antivenom

An antivenom for the Sydney Funnel-web Spider was first developed for clinical use in 1981 by Dr Struan Sutherland and his team at the Commonwealth Serum Laboratories. No deaths have occurred since its introduction. At the same time Sutherland experimentally established the effectiveness of the compression/immobilisation first aid technique for funnel-web bite. Much of the venom for this research was supplied through a funnel-web venom milking program at the Australian Reptile Park. This antivenom has also been effective against other dangerous funnel-web spider species. As well, it has been successfully used in cases of mouse spider envenomation. Antivenom is held at major city and regional hospitals.

Other dangerous funnel-web species

All suspected bites by any funnel-web spider should be regarded as potentially dangerous and treated accordingly. Besides Atrax robustus several other species have been sporadically involved in life threatening envenomations. They include the Blue Mountains Funnel-web Spider (Hadronyche versuta) and the Southern and Northern Tree Funnel-web Spiders (H. cerberea and H. formidabilis).

First aid for Funnel-web Spider bites — why and how

Despite the availability of an effective antivenom, correct and immediate first aid is still an essential requirement for funnel-web spider (and mouse spider) envenomation. The recommended first aid technique is pressure/immobilisation (as for snake bite) and this must be done as quickly as possible.The pressure/immobilisation technique compresses surface tissues and reduces muscle movement, greatly slowing the lymphatic flow.

Spider bites usually take place on a limb. A pressure bandage should be applied as soon as possible after a bite has occurred. This should be applied as tightly as for a sprained ankle, starting from the bitten area and binding the entire limb above the bite. A rigid splint should be bound onto the limb to prevent limb movement. The patient should be kept as quiet as possible and medical attention sought. If possible, keep the spider for positive identification.

Funnel-web Spider FAQs

Can funnel-webs jump?

Despite what many people think, funnel-webs can’ t jump. However they can move quickly, and they will rear up when irritated and make sudden lunges when striking

Can funnel-webs swim?

Wandering funnel-webs spiders often fall into backyard swimming pools and they can stay alive for hours. They can’t swim but they can trap a small bubble of air in hairs around the abdomen, which aids both breathing and floating, so it should not be assumed that a spider on a pool bottom has drowned. As they gradually get waterlogged, their buoyancy decreases and they eventually sink and drown. Funnel-webs have been known to survive 24-30 hours under water.

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