Sydney Funnel-web vs. Black-house

Article | Updated 4 weeks ago

It is easy to mistake these two species of spider.

Black-house spiders and Sydney funnel-web spiders are both dark, robust common Australian spiders.

The distinctive funnel-shaped web of the Black-house spider, made of lace-like sheet webbing, is secreted in a crevice or hole and usually T-shaped, and is often mistaken for that of the deadly Sydney funnel-web spider. However, while Black house spiders occur all around Australia, the Sydney funnel-web spider has not been found in Western Australia and only occurs in the eastern parts of the country.

Outline of Australia

Sydney Funnel-web distribution map
Image copyright WA Museum 

These two spiders are both robust and stocky, are dark to black in colour, and are active at night. But this is where the similarities end.

Although these two spiders are similar in terms of physical features, colour, and behaviour, there are many key elements that are different, and therefore help to tell the harmless from the potentially deadly.

The harmless Black-house spider has an abdomen covered densely with velvety hairs. It has non-parallel (diaxial) fangs, and can grow up to 2 cm (females, 1 cm for males).

Image of a large black spider

Black house spider - Badumna insignis
Image copyright 
Robert Whyte - https://www.flickr.com/photos/robertwhyte/ 

The web of a Black-house spider is always built at height on a structure, such as a tree trunk or building. The web is funnel-like in shape, and has an entrance of sticky zigzag threads. This spider prefers dry habitats. In the bush, they usually build isolated webs in the dry bark of trees and in rockeries. Around buildings several webs can be found close together, mostly in corners and around windows and doorways.

Image of a large black spider on a web

Black house spider - Badumna insignis
Image copyright Angus Veitch - https://www.flickr.com/photos/gusveitch/sets/  

The diet of a Black-house spider consists of other spiders and insects (especially flying insects. A Black House spider will wait in their web for prey to become trapped.

The Black-house spider is a shy species and seldom bites humans. Despite the fact that the bite is venomous and can cause illness, the Black-house spider is not considered dangerous and is not deadly.

In comparison, the Sydney Funnel-web has an almost hairless carapace that appears shiny, smooth and glossy. It has parallel (paraxial) fangs, and can grow up to 3 cm (females, 2.5 cm for males).

The web of a Sydney Funnel-web is always on the ground, for example in a burrow or under a rock. The web is also funnel-like in shape, but has no particular shape to the entrance, and is rather untidy.

Funnel-web spiders prefer cool, moist and sheltered habitats. They can be found both in forests and urban areas where they burrow habitats under rock, in rotting logs, crevices, rough-barked trees and dense shrubberies.

The diet of a Sydney Funnel-web consists of other spiders, small skinks and lizards, snails, frogs, and ground-dwelling insects. A Sydney Funnel-web will wait until its prey walks across the zigzag threads of its web, at which point it will rush out and subdue its prey by injecting venom.

Funnel-web spiders are very aggressive and are among the deadliest spiders in the world. The venom of the male Sydney funnel-web spider is very toxic and the bite can cause serious injury or death in humans if left untreated. However, since the introduction of antivenom, no deaths have occurred.

Further Information

The Australian Museum of Sydney is also a good resource to find information about spiders. Here (http://australianmuseum.net.au/Funnel-web-Spiders-Group) you will find a detailed factsheet about funnel-web spiders’ features and first aid recommended in case of bite. The Australian Museum also provides fact-sheets about the Sydney Funnel-web spider (http://australianmuseum.net.au/Sydney-Funnel-web-Spider ) and the Black-house spider (http://australianmuseum.net.au/Black-House-Spider-Badumna-insignis/ ).

Resources and sources

http://www.reptilepark.com.au/animalprofile.asp?id=126

http://www.dinosoria.com/atrax_robustus.htm

http://www.reptilepark.com.au/animalprofile.asp?id=126

http://www.arachne.org.au/01_cms/details.asp?ID=1853

http://australianmuseum.net.au/Funnel-web-Spiders-Group

http://australianmuseum.net.au/Sydney-Funnel-web-Spider