Last weekend at Eurardy Reserve (WA) ecologist Vanessa Westcott was working with the Citizen Science volunteers when they spotted the home of a trapdoor spider.
The twigs and leaf litter radiating out from the burrow are fastened with web to the rim of the hole. They're used as ‘trip lines’ so unassuming insects (ants, beetles, cockroaches, moths) walking by can be detected by the spider, grabbed and eaten!
Female trapdoor spiders spend their entire life in their burrow or in close proximity. They can live for up to 20 years and as they grow they must widen their burrow and extend the size of their trapdoor. If you look closely at the trapdoor of some species you can see concentric rings where the home owner has added to the outside edge of her trapdoor.
The burrow is deep enough to ensure that air in the lower burrow remains humid and relatively cool in summer (can be up to 30 cm deep).
Male spiders are smaller, have shorter life spans and are more mobile as they must search for a mate.
Both Eurardy Reserve and Charles Darwin Reserve, owned and managed by Bush Heritage Australia, fall within the natural range of the Nationally Vulnerable Shield-backed Trapdoor Spider which is endemic to the mid-west of Western Australia. Both reserves also provide suitable habitat for the species - york gum woodlands and acacia shrublands.
There are a number of other rare and more common species of trapdoor spider found in the region. To find out more check out this info booklet. It is not possible to identify which species of spider you have based on the trap door alone, so we can't be sure which one we have here.
The Australian Museum website is another good source of information on these fascinating critters.