Wildlife Wednesday: Trapdoor Spider
This week Wildlife Wednesday is about the elusive and fascinating Trapdoor Spider! There is so little that is fully known about these creatures, but the little that has been discovered is enough for us to be drawn into the marvels of yet another intriguing creepy crawlie.
Did you know there are around 120 recognized species of trapdoor spiders and are common all throughout the range of Asia, Australasia, North & South America, Europe, and Southern Africa?
They are sedentary ground-dwelling spiders, the correct terminology for this being a ‘mygalomorph’. They are very fast-moving spiders and get their name because as you can see in the pictures, they literally construct a burrow lined with silk and a perfectly formed cork-lid which serves as a trapdoor when the spider hunts. The burrow the female constructs usually runs 15-25cm straight down into the ground. However, there are certain species that do not build burrows, but instead rely on a silken tube with the trapdoor in bark crevices. The lids are very hard to spot as they blend perfectly into the undergrowth being constructed of soil, vegetation and silk. The door is hinged on one side with silk; then at night the spider waits just under the lid holding it slightly ajar, and then feels the vibrations of prey moving above her approaching the door, before bursting out of her hole on the very unsuspecting victim of prey. The trapdoor spider’s fangs inject venom into the prey. These fangs consist of tiny barbs, which behave like rakes to move soil around when the spider digs its burrow. Some of the most common prey caught includes crickets, beetles, moths, and grasshoppers.
Some trapdoor spiders physically hold their door down with the help of specially designed fangs while pushing against the walls of the burrow with their legs when there is a threat nearby, particularly so from the Spider Hunting Wasp, who upon finding the burrow, will run in and sting the spider to immobilise it – not to kill it, for Spider Hunting wasps don’t eat the spider, they need it alive to act as an incubator for their single egg they lay on the abdomen of the spider!!
The bite from this spider is of low risk to humans, nonetheless, don’t provoke them to cause aggressive behaviour as they can bite and it is very painful!
In the arthropod world, it is quite common for the male to have a much shorter life span than the female, but it is excessive in this species, with females living on average 20 years while males die soon after mating with a few females!
There is another fascinating thing the female of this species does, that humans are yet to discover the exact trigger of. There is something that the spiders inherently respond to, knowing the time has arrived for her babies to leave the nest. When this time arises, mommy lays down a silk ‘carpet’ from their burrow in the ground to the nearest tree, and all the way up the tree trunk as high as it can go. Then the babies leave their nest in the ground, follow their silk aisle, and our guess is that they become wind-borne from the tops of the trees, and the survivors then begin their new lives as adults.
There is so much we have yet to learn about the world in which we live!