Sydney Brown Trapdoor Spider

Introduction

The Sydney Brown Trapdoor Spider lives in silk-lined burrows, which are commonly found in the lawns, gardens and bushland of Sydney.

Identification

The Sydney Brown Trapdoor Spider's body has a dusty look about it, with golden brown hairs on the carapace (body) and greyish bars on the abdomen. The carapace is usually weakly arched in side profile. Their eyes are arranged in two compact rows. Males usually have a small double spur halfway along their first leg and have thick 'boxing glove' palps (front pair of limbs). Females are larger than males, and tend to be harder to identify to species level. These spiders are quite timid, although the male may rear up if threatened, and they are not dangerously venomous. Trapdoor spiders are quite different in appearance from the shiny brown-black funnel-web spiders, with which, being similar in size, they are often confused. Also unlike funnel-webs, they have short, blunt spinnerets.

Habitat

The Sydney Brown Trapdoor Spider can occur in large numbers in urban and bushland areas.

Distribution

The Sydney Brown Trapdoor Spider is known from the George's River in southern Sydney to the Hunter River Valley in the north and just west of Parramatta in the west. However there are a number of other Arbanitis species found in the Sydney region.

Feeding and diet

The Sydney Brown Trapdoor plays an important role in controlling ground-dwelling insects and other arthropods such as beetles, cockroaches, crickets, slaters, spiders and even moths that stray too near the burrow entrance.

Other behaviours and adaptations

Unlike funnel-web spider burrows, the burrows of the Sydney Brown Trapdoor Spider have no silk trip-lines extending out from the rim and they are found in more open ground. Despite their common name, most Arbanitis species do not make trapdoors but have an open burrow with a silken rim attached to the surrounding grass or leaf litter. An exception is another Sydney species, M. gracilis, which makes a light, wafer-like trapdoor.

Breeding behaviours

Male trapdoor spiders have a small double mating spur halfway along the first pair of legs, which is a distinction from similarly sized male funnel-webs that have a large spur on the second pair of legs instead. Males tend to wander throughout the year.

Danger to humans

Although often mistaken for funnel-web spiders, the bite of a trapdoor spider is not dangerous, but may be painful and cause some local swelling. Apply a cold pack to relieve pain and seek medical attention if symptoms persist.

References

• York Main, B. 1976. Spiders. The Australian Naturalist Library, Collins, Sydney.
• Brunet, B. 1996. Spiderwatch: a guide to Australian spiders. Reed/New Holland.
• Simon-Brunet, B. 1994. The Silken Web: a natural history of Australian spiders. Reed Books.
• Wishart, G. 2006. Trapdoor spiders of the Genus Misgolas (Mygalomorphae: Idiopidae) in the Sydney Region, Australia, with notes on synonymies to M. rapax. Records of the Australian Musuem 58(1): 1-18