Funnel Web Spiders

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    Fast Facts Funnel Web Spiders

    Funnel Web Spiders - What you Need to know

    Funnel-web spiders, notorious residents of eastern Australia, are renowned for their prominent role in the region's spider population. These spiders are categorised into 36 species and fall under three genera: Hadronyche, Atrax, and Illawarra.
    They range in size from medium to large, with body lengths varying between 1 cm and 5 cm. Males tend to have a lighter build compared to females. Their body colour ranges from black to brown, and they are characterised by a hard, glossy carapace with sparse hair covering the front part of their body. A distinct feature of these spiders is their spinning organs, or spinnerets, located at the end of the abdomen. In Atrax species, these spinnerets are longer and easily noticeable, while in Hadronyche and Illawarra species, they are often shorter.

    Widely regarded as some of the world's most dangerous spiders, funnel-web spiders possess a highly toxic and fast-acting venom. Their bite is not only painful but also rapidly impacts the central nervous system, leading to severe shock and shutdown of bodily functions. Consequently, it's essential to exercise caution in areas where these spiders are present.

    While not every species is considered dangerous, a number of them are infamous for their extremely potent and rapidly effective venom. The male Sydney Funnel-web Spider, scientifically known as Atrax Robustus, is likely accountable for all known fatalities (13 in total) and numerous severe bite incidents. This extraordinary spider has woven itself into the cultural fabric of Sydney and the Central Coast, becoming a symbol of both dread and intrigue for the city's residents. Despite no fatalities being reported since the introduction of an antivenom in 1981, the Sydney Funnel-web Spider continues to hold a notorious status among the people of the East Coast of Australia.

    In the Central Coast region, there are a range of common spiders and the prevalence of funnel-webs is particularly high due to the warm and humid weather conditions experienced during the summer months. These environmental factors create ideal habitats for these spiders, increasing encounters with humans and highlighting the importance of awareness and safety measures in these areas.

    Identifying funnel-web spiders

    When it comes to identifying funnel-web spiders, paying close attention to specific physical characteristics is key. These spiders, known for their potentially dangerous nature, possess a set of unique features that distinguish them from other spider species. Observing these characteristics carefully can help in accurately identifying funnel-web spiders. 

    Here are the identifying characteristics to look for:

    • 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 (a male trapdoor spider has the first leg modified.)
    • Male second leg: 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 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.

    What to do when you find a Funnel Web Spider

    If you come across a Funnel Web spider, there's a valuable way to contribute to public safety while safely removing the spider from your property. Carefully capture the spider in a container with air holes and a small amount of moist soil or paper towel, ensuring you do not put yourself at risk. Then, take it to the Australian Reptile Park in Somersby. The park runs a significant Spider Venom Program where they extract venom from Funnel Web spiders to produce life-saving antivenom. This program plays a crucial role in providing antivenom to hospitals across Australia, potentially saving lives. For more details on this program and how you can help, visit Australian Reptile Park's Spider Venom Program. Remember, safety is paramount, so only attempt to capture a spider if you can do so without endangering yourself.

    Where Funnel Web Spiders Live

    Funnel-web spiders in Sydney primarily inhabit the moist upland forest regions of the Hornsby Plateau to the north and the Woronora Plateau to the south. These areas, rich in sheltered burrow habitats, are found both in bushland and gardens. In contrast, the drier, flatter regions of Western Sydney and the Cumberland Plain host fewer funnel-webs. However, their population increases again near the foothills of the Blue Mountains. 

    The Central Coast/ Sydney region is home to two common funnel-web species: the Sydney Funnel-web Spider (Atrax robustus) and the Southern Tree-dwelling Funnel-web Spider (Hadronyche cerberea). Additionally, the Blue Mountains Funnel-web Spider (Hadronyche versuta) is present in the area, predominantly to the west and south of Greater Sydney.

    Within the Hadronyche genus, several groups of related species are recognised, including:

    1. The cerberea group, mostly found south of the Hunter River down to Tasmania, with the exception of one species, the Northern Tree-dwelling Funnel-web Spider (Hadronyche formidabilis), which is the largest of the funnel-web spiders, having a body length of up to 5 cm.
    2. The infensa group, located north of the Hunter River and extending into south-east Queensland.
    3. The adelaidensis group, isolated in the dry forests of South Australia's Gulf Region, is unique for being the only trap-door building funnel-web spiders.
    4. The 'lamington' group, comprising several species confined to distinct rainforest areas in New South Wales and Queensland.
    5. The anzes group, consisting of a single species found in rainforests north of Cairns in north Queensland.

    Additionally, Illawarra wisharti is a unique species in its own genus, isolated in the wet forests of the Illawarra region of New South Wales.

    Sheltered Retreats

    Funnel-web spiders seek out damp, cool, and protected environments for their burrows, such as beneath rocks, inside and under decomposing logs, within crevices, and in holes caused by rot or borers in trees with rough bark. In garden settings, they are drawn to rockeries and thick shrubbery, and are seldom found in more exposed areas like lawns.

    Heavy rainfall can lead to the flooding of funnel-web burrows and the temporary shelters of male funnel-webs, which in turn increases their activity levels. These spiders are particularly sensitive to dehydration, so they are more active outside their burrows in high humidity rather than in dry conditions. Their activity predominantly occurs at night. Gardeners and individuals working with soil may come across funnel-webs in their burrows throughout the year.

    Signs of a Funnel-Web Spider's Presence: Identifying Burrows and Silk Trip-Lines

    An early indicator of a funnel-web spider's presence is the distinctive silk trip-lines that often extend from the entrance of their burrows in many species. These trip-lines serve as a warning system for the spider, signalling the presence of potential prey, mates, or threats.

    In fact, when you see a spider burrow surrounded by noticeable silk trip-lines, it's a strong indication that the burrow belongs to a funnel-web spider.

    The burrow entrance of a Sydney Funnel-web Spider typically features a funnel-like silk entrance 'vestibule,' inside which is a collapsed, tunnel-like structure with one or two narrow openings. This tunnel leads to a short chamber at the surface, from which the burrow descends. Often only weakly lined with silk, these burrows usually do not exceed 30 cm in depth. The spider, primarily active at night, waits just inside the entrance with its front legs on the trip-lines. When a beetle, cockroach, or small skink—common funnel-web prey—triggers the lines, the spider quickly emerges to capture its meal, swiftly immobilising it with venom from its large fangs. Funnel-web spiders may also hunt on the ground near their burrows.

    Burrows are typically found in damp, shaded areas such as rockeries, dense shrubs, logs, and leaf litter. A small, tidy hole with a silk collar that doesn't extend much beyond the rim could be the home of a trapdoor spider (the common Brown Trapdoor Spider, for example, doesn't construct a 'door' for its burrow). Other creatures that might inhabit similar holes include mouse spiders, wolf spiders, or insects, often cicadas or ants.

    Mating Behaviour and Wandering of Mature Male Funnel-Web Spiders

    Once male funnel-web spiders reach maturity, they abandon their burrows and embark on a journey, particularly during the summer and autumn months, in search of female spiders. The females release pheromones in their silk trip-lines, which assist the males in locating and recognising their burrows. Prior to mating, the male spider constructs a small silk sperm web and deposits a sperm droplet onto it from his abdominal genital pore. He then transfers the sperm to his palps' mating organs for storage.

    The male uses the spur or spines on his second legs to grasp the female during the mating process. Mating involves a considerable amount of interaction before the female accepts the male. Both spiders stand with their first legs elevated, facing each other, as the male employs his mating spurs to engage across the bases of the female's second legs. The male then proceeds to inseminate the female by inserting his palpal organs into her genital opening located on the underside of her abdomen.

    Understanding the Male Funnel-Web Spider's Role in Envenomation Incidents

    All recorded fatalities from funnel-web spider envenomations have been attributed exclusively to male spiders. This phenomenon can be attributed to a mix of spider behaviour, venom composition, and even historical factors. Male funnel-webs, particularly active during the warmer months (November to April), roam at night in search of female spiders. It's not uncommon for them to inadvertently enter homes or garages, especially in suburban areas with houses built on concrete slabs that provide easy access under doors.

    The venom of the male Sydney Funnel-web Spider is notably potent due to a specific component called Robustoxin (δ-Atracotoxin-Ar1), which has a profound impact on the nervous systems of both humans and monkeys, unlike the venom of other mammals. The absence of Robustoxin in the venom of female Sydney Funnel-web Spiders is likely why their bites haven't resulted in fatalities. Nonetheless, it's important not to underestimate bites from female spiders or any funnel-web species, as not all demonstrate this gender-based difference in venom toxicity. The Sydney metropolitan area, home to over four million people, is at the heart of the Sydney Funnel-web Spider's distribution. This high population density in the region significantly increases human encounters with this spider, a consequence that traces back to the 1786 decision to establish a British colony in the area. As a result, one of the world's most densely populated regions coincides with the habitat of one of the most dangerous spider species.

    Development of the Sydney Funnel-web Spider Antivenom

    The antivenom for the Sydney Funnel-web Spider was first developed in 1981 by Dr. Struan Sutherland and his team at the Commonwealth Serum Laboratories, marking a significant advancement in clinical treatment. Since its introduction, no fatalities from Sydney Funnel-web Spider bites have been reported. Dr. Sutherland also played a crucial role in experimentally validating the compression/immobilisation technique as an effective first aid measure for funnel-web spider bites. A substantial amount of venom required for this research was sourced from a venom milking program at the Australian Reptile Park, here on the Central Coast of NSW. This antivenom has not only proven effective against other dangerous funnel-web spider species but has also been successfully used in treating envenomations by mouse spiders. The antivenom is readily available at major hospitals in both city and regional areas.

    Essential First Aid for Funnel-Web Spider Bites

    Correct and immediate first aid remains crucial for treating bites from Funnel-web Spiders (or mouse spiders), despite the existence of an effective antivenom. The recommended first aid method is the pressure/immobilisation technique, similar to that used for snake bites, and it should be applied as swiftly as possible. This technique involves compressing surface tissues and minimising muscle movement to significantly slow down lymphatic flow.

    Most spider bites occur on limbs. It's important to apply a pressure bandage as quickly as possible following a bite. The bandage should be as tight as one would use for a sprained ankle, starting from the bite site and covering the entire limb above the bite area. Additionally, a rigid splint should be used to immobilise the limb. The patient should be kept calm and still, and medical assistance must be sought immediately, even if symptoms don't seem apparent at first. Severe envenomation constitutes a medical emergency. If it is safe, retain the spider for accurate identification.

    Sydney Funnel Web Spider- Infamous Notoriety

    The Sydney Funnel-web Spider is perhaps the most infamous spider, known for its formidable reputation. While much of this reputation is based on the toxicity of its venom and is well-deserved, some aspects are overstated. Like snakes, these spiders are not aggressive by nature and generally prefer to avoid human interaction as much as humans prefer to avoid them.

    Characteristics of the Sydney Funnel-web Spider

    Sydney Funnel-web spiders are identified by their shiny, dark brown to black appearance and distinctive finger-like spinnerets at the end of their abdomen. The males are recognizable by a prominent mating spur on the middle of their second pair of legs. When threatened, Sydney Funnel-webs exhibit aggressive behaviour, rearing up and displaying their sizable fangs.

    Habitat and Range of the Sydney Funnel-web Spider

    The Sydney Funnel-web Spider (Atrax robustus) is found in New South Wales, ranging from Newcastle to Nowra, and extending westward to Lithgow. They are particularly prevalent in the forested upland regions surrounding the central Cumberland Basin's lower, more open country. This includes areas like the Hornsby Plateau in the north, the foothills of the Blue Mountains in the west, and the Woronora Plateau to the south. Their presence is less common in central-western Sydney, as well as the sandy coastal areas of the eastern suburbs and around Botany Bay. These spiders thrive in sandy clay, shale, or basaltic soils, which retain moisture more effectively.

    Feeding Habits of Funnel-web Spiders

    Funnel-web spiders establish their burrows in protected areas beneath logs and rocks, seeking out environments that are both cool and humid. These spiders are quick to respond when potential prey, such as beetles, cockroaches, small lizards, or snails, activate the silk trip-lines they've set around their burrows. After capturing their prey, funnel-web spiders retreat to their burrows to consume their catch.

    Unique Behaviours and Adaptations of Sydney Funnel-web Spiders

    Male Sydney Funnel-web spiders are known for their tendency to venture into residential areas and occasionally fall into swimming pools, where they can survive for several hours. They may also inadvertently enter houses and become trapped. Sydney Funnel-web spiders possess one of the most toxic venoms to humans among spiders, yet not all bites are lethal. The venom from juvenile and female Sydney Funnel-web Spiders is considerably less toxic. Furthermore, these spiders do not jump at, chase people, or inhabit houses, contrary to common urban myths.

    Funnel-web spiders can become dehydrated in dry daytime conditions and are also vulnerable to predators like birds and lizards. Males, who spend the night seeking a mate, need to find shelter at daybreak in dark, moist, and cool places, such as a cavity under a rock or an outdoor shoe.

    Common Spider Misidentifications

    Several other spider species are frequently mistaken for funnel-webs, including mouse spiders, trapdoor spiders, and Black House Spiders.


    Funnel-web Spiders and Human Safety

    Bites from funnel-web spiders are dangerous, and immediate first aid using the pressure bandage/immobilisation technique (similar to snake bites) is essential. Victims should be taken to a hospital and administered antivenom if necessary. The venom contains a neurotoxin that affects the human nervous system and can be fatal in severe cases. However, there have been no deaths attributed to funnel-web bites since the introduction of antivenom.

    Addressing Funnel-web Spider Concerns on the Central Coast

    Funnel-web spiders are a significant presence on the Central Coast, with their prevalence influenced by the region's warm and humid climate. Understanding their behaviour, habitat, and the potential risks they pose is essential for residents in these areas. Should you suspect a spider problem in your home or surroundings, it's important to take appropriate measures to ensure safety. For expert assistance and peace of mind, don't hesitate to contact the team at Coastwide Pest Control, who are well-equipped to handle any spider-related concerns you may have. Their expertise and experience make them a reliable resource in managing and resolving issues with these intriguing yet potentially dangerous creatures.