Identification
Due to their size, colour and large fangs, these spiders are often thought to be Sydney Funnel-web Spiders, but the Sydney Funnel-web only occurs in New South Wales.
A Melbourne Trap-door Spider
Illustrator: Graham Milledge / Source: Museum Victoria
The Melbourne Trap-door Spider is a large robust spider with females growing to a body length of 35 mm and males to 25 mm. They are generally light to dark brown in colour. The abdomen is often paler than the rest of the spider with a dark, mottled rib-like pattern on the upper surface.
The male is similar to the female except that some specimens have golden hairs on the cephalothorax (head-section).
The Melbourne Trap-door Spider has parallel downward pointing fangs, so in order to bite it must rear back and bring its fangs down in a striking action. People who see a spider behaving like this often assume that the spider must be a Sydney Funnel-web.
However, this method of striking is characteristic of all the so called ‘primitive spiders’ or mygalomorphs such as trap-doors, funnel-webs, mouse spiders and whistling spiders due to this parallel arrangement of their fangs.
A female Melbourne Trap-door Spider. Note the pattern on the abdomen.
Photographer: Graham Milledge / Source: Museum Victoria
Habitat & Biology
The Melbourne Trap-door Spider is a common ground-dwelling spider often encountered by the weekend gardener when digging soil or moving rocks.
Both males and females dig silk-lined burrows up to 40 cm deep in soft earth. Despite the reference in the common name, the entrance of the spider's burrow does not have a 'trap-door'. The spider feeds at night, catching its prey by setting several strands of silk radiating out from the burrow entrance. The spider sits just inside the entrance of the burrow and waits for an insect to ‘trip’ these silken threads. The spider then rushes out and grabs the prey.
Males leave the burrow when mature and roam in search of a mate. This usually occurs in autumn or early winter and spiders may wander into houses, garages, swimming pools, etc.
Trap-door spiders have long life spans and may live from 5 to 20 years.
A Melbourne Trap-door Spider
Photographer: Graham Milledge. Source: Museum Victoria
Bites
Due to the size of the fangs, the trap-door spider can inflict a deep, painful wound, but the venom is not known to cause medical problems. The two long appendages at the back of the spider are spinnerets, from which silk is extruded.
Further Reading
Brunnet, B. 1994. The Silken Web – A Natural History of Australian Spiders. Reed Books: Melbourne.
Lindsey, T. 1998. Spiders of Australia. New Holland Publishers: Sydney.
Walker, K. L., Yen, A. L. and Milledge, G. A. 2003. Spiders and Scorpions commonly found in Victoria. Royal Society of Victoria: Melbourne.