Animal Species:Trapdoor Spiders
Most trapdoor spiders are misleadingly named, as not all species make a door for their burrows. These highly camouflaged entrances are almost undetectable, unless the door is open.
Trapdoor spiders have short, blunt spinnerets. Males usually have a small double spur halfway along their first leg. Females are larger than males, and tend to be harder to identify to species level. These spiders tend to be quite timid, although the male may rear up if threatened.
The common name covers several families of spiders, including the Idiopidae, Actinopodidae, Ctenizidae, Migidae and Cyrtaucheniidae. The Brown Trapdoor (Misgolas sp) and the Spotted Trapdoor (Aganippe sp) Spiders belong to the family Idiopidae. They include a wide variety of types, many of which are adapted to drier habitats.
Brown Trapdoor Spiders are dull brown spiders with a cover of paler gold hairs on carapace ("dusty appearance"), which is usually weakly arched in side profile. There are often pale bars across the abdomen. Males have thick 'boxing glove' palps. Brown Trapdoor spider eyes are arranged in two compact rows.
Sigillate Trapdoor Spiders are brown spiders with a strongly arched glossy carapace and 4 - 6 hairless spots (sigillae) on top of the abdomen. Their eyes are arranged in three distinct rows.
Spiders commonly mistaken for Trapdoors include: Funnel-web Spiders and Mouse Spiders. Also, as there are several families of Trapdoor Spiders, identification to species level can be difficult without a detailed key.
1.5 cm - 3 cm in body length
Funnel-web Spiders and Mouse Spiders.
The female will lay her eggs several months after mating, and protects them within her burrow. When the juveniles have hatched, they remain for several months before dispersing on the ground. They will then make their own miniature burrows. Each time the spider grows bigger, it has to widen its burrow and, in the door-building species, add another rim to the door. In undamaged trapdoors, annual concentric rings can be seen.
Trapdoors have a long life span, between 5 to 20 years, and take several years to reach maturity. Females stay in or near their burrows, whereas males leave their burrows once mature, and go in search of a mate.
Mating and reproduction
Mature male Trapdoor Spiders wander during humid weather in search of a mate. Mating takes place within the female's burrow. The male usually escapes being eaten in order to mate with several females, before dying.
In urban areas Brown Trapdoor Spiders probably play an important role in controlling garden pests, and since they are not considered to be a major threat to humans, it is best just to leave them alone.
Danger to humans and first aid
Brown Trapdoor Spiders are often mistaken for Funnel-web spiders but their bites are not dangerous. Local pain and swelling may occur. Sigillate Trapdoor Spider bites may also cause local pain and swelling. There is one report of unspecified 'severe effects' from a Sigillate Trapdoor Spider bite.
Seek medical attention if symptoms persist. Collect spider for a positive identification.
Dr Mike Gray