Captive care of the red trapdoor spider (Idiopidae)

Description
The mygalomorph trapdoor spider belongs to the family Ctenizidae (Araneae, Idiopidae). These are all large spiders that have short spines on the lateral surface of the anterior legs but lack the hairy appearance of the theraphosidae or tarantulas. Trapdoor spiders have what is known as a rastellum on their chelicerae and they use this to dig their deep, tubular burrows. The legs are quite short but rather robust with an overall colouration of rust red / orange with a definite dark brown line that circles the outer most edges of the carapace. The fovea is deeply procurved and the dorsal abdomen area clearly shows the dark patch of the heart known as the thoracic mark. An adult female has a body length of approximately 3cms with a leg span around 6cms. This is a widespread genus and is reported from Africa, south and Central America, India and even Asia. Trapdoor spiders inhabit very specific environments and once one burrow is located, several more are usually to be found nearby but surprisingly little is known about trapdoor spider behaviour because of their secluded lifestyle. This is a particularly aggressive species and handling isn't recommended as the spider will assume the threat posture and attack repeatedly especially when it has been removed from its burrow.

Housing
As this species likes to dig deep burrows, a taller container is preferred. A size of approximately 15 X 15 X 30cms tall will be ideal. Substrate should consist of a mix of slightly damp peat-free compost, sand and vermiculite and on top of this there should be a scattering of leaf litter (dried leaves and twigs etc). The substrate should be at least 15cms deep to allow for burrowing as this species cannot survive out in the open. A small hole can be made in the substrate to give the spider a starting point and once introduced, it should begin excavations under the cover of darkness. Ideal temperatures are between 21oC and 30oC with a humidity of around 65%.

Burrow Construction
Over the following few nights, the spider will deepen its burrow and slowly begin to form the trapdoor. By gathering pieces of the surrounding substrate and leaf litter, the spider will spin these together to form a thin, hinged door. Over time, this door becomes gradually thicker until it is almost impossible to see when tightly closed. Pieces of leaves and twigs are incorporated into the burrow entrance and door and used by the spider to increase the prey-sensing area. The depth and shape of the burrow varies depending on the container used but is usually a simple slightly curving shape with no definite chamber at its base. The inside walls of the burrow are heavily lined with silk, as is the underside of the door. Attempts to open the trapdoor are usually resisted by the spider which pulls the door tightly shut upon detection of intrusion. Further attempts result in the door being pulled further into the burrow, the spider using the claws of the first two pair of legs.

Feeding and Prey Capture
Prey items consist of any suitably sized insects (crickets, mealworms, flies etc) and these can simply be dropped into the container. A small surface area means the prey will come into contact with the spiders' retreat more frequently, giving it a greater chance of success. The spider will sit just inside the burrow entrance with the door held slightly open, waiting the vibration of passing prey and once it comes within range, will emerge with lightening speed to grab the prey with its chelicerae, palps and front legs. The rear legs and abdomen never leave the safety of the burrow and within a split second the spider and prey are gone. The trapdoor is securely closed while feeding and the discarded remains will be ejected some distance from the burrow entrance. Excrement is also deposited outside the retreat by means of squirting.

Longevity
Exact longevity is unknown but may be as long as 10 - 15 years (similar to tarantulas) in captivity.

References
Retreat architecture and construction behavior of an East African Idiopidae trapdoor spider (Araneae, Idiopidae)
Frederick A Coyle, Robert E Dellinger and Robert G Bennet. Bull. Br. arachnol. Soc. (1992) 9 (3), 99-104.

Southern African Spiders - An identification Guide. Martin R Filmer. Struik 1991.



Notes on the trapdoor spider Idiopis. Randy J Mercurio. Journal of the British Tarantula Society Vol.15, No.4 (2000).



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