Trapdoor spiders, members of the family Ctenizidae, are medium-sized mygalomorph
spiders that construct burrows with a cork-like trapdoor made of soil,
vegetation and silk. Some similar species are also called trapdoor
spiders, such as the Liphistiidae, Barychelidae, Cyrtaucheniidae and some
Idiopidae and Nemesiidae. Some Conothele species do not build a burrow, but
construct a silken tube with trapdoor in bark crevices.
Ecology and behavior The trapdoor is difficult to see when it
is closed because the plant and soil materials effectively camouflage it. The
trapdoor is hinged on one side with silk. The spiders, which are usually
nocturnal, typically wait for prey while holding on to the underside of the door
with the claws on their tarsi. Prey is captured when insects, other arthropods,
or small vertebrates disturb the 'trip' lines the spider lays out around its
trapdoor, alerting the spider to a meal within reach. The spider detects the
prey by vibrations and, when it comes close enough, leaps out of its burrow to
make the capture. A hungry individual will wait halfway
outside of its burrow for a meal. Male trapdoor spiders can overcome the
female's aggressive reactions to their approach, but it is not known how.
Females never travel far from their burrows, especially if they have an egg
sac. During this time, the female will capture food and regurgitate it to feed
her spiderlings. Enemies of the trapdoor spider include certain pompilids, which
seek out the burrows and manage to gain entrance. They sting the owner and lay
their eggs on its body. When the egg hatches, the larva devours the spider
alive. Unlike other mygalomorph spiders, the
Ctenizidae have a rastellum on the chelicera. Resembling "teeth" or "barbs"
on each fang, this modification is used to dig and gather soil while
constructing a burrow. They use their pedipalps and first legs to hold the
trapdoor closed when disturbed. There are about 120 species of trapdoor
spiders. The Spider Wasps of the subfamily
Ctenocerinae found in the Neotropics, Africa and Australia are specialised
hunters of trapdoor spiders. Taxonomy
The taxonomy of trapdoor spiders is currently not well understood in the
United States and many species of the common genus Ummidia remain undescribed.
Ummidia is distributed across the southern United States. Bothriocyrtum
californicum is the common trapdoor spider of the Pacific Coast. The strange
genus Cyclocosmia includes seven species, found in Florida, Eastern
Alabama, Georgia, North Carolina, Mexico to Guatemala, China, Thailand and
Canada. The discontinuous distribution is indicative of a basal genus that was
affected by continental drift. The spiders of this genus are unusual in
having a mask-like hardened plate on the opisthosoma, which seems to act as a
second door to exclude predators, like the spider wasps. There is a narrow part
of the burrow of these spiders where the abdominal shield just barely fits.
Cyclocosmia torreya builds burrows in moss banks along the Apalachicola River
in Florida. Other genera of trapdoor spiders are found in other areas of the
world. They actually may be more common than we may think because of their
cryptic habits. They do tend to be localized in distribution and as such
may be subject to extinction because of local habitat destruction.
Genera The categorization into subfamilies
follows Raven Ctenizinae Thorell, 1887
†Baltocteniza Eskov & Zonstein, 2000 Early Eocene Baltic amber
Bothriocyrtum Simon, 1891 — USA, Mexico, Taiwan
Cteniza Latreille, 1829 — Europe, Central Asia
Cyclocosmia Ausserer, 1871 — USA to Guatemala, Thailand, China
Cyrtocarenum Ausserer, 1871 — Greece, Turkey
†Electrocteniza Eskov & Zonstein, 2000 Early Eocene Baltic amber
Latouchia Pocock, 1901 — Asia Stasimopus Simon, 1892 — South Africa
Pachylomerinae Simon, 1889 Conothele Thorell, 1878 — Australian
region Hebestatis Simon, 1903 — Costa Rica, USA
Ummidia Thorell, 1875 — America, Mediterranean, Japan, Taiwan
Habitat Most Trapdoor spiders live in burrows.
They live in warm places such as China, North America, South America, Africa and
Japan. Trapdoor spiders don't live in webs. However, they make silk hinged
doors that blend with their habitat. Not all Trapdoor spiders use trapdoors.
See also List of Ctenizidae species
List of spider common names Spider families
Footnotes References
Raven, R.J. 1985 The spider Infraorder Mygalomorphae: cladistics and
systematics. Bulletin of the American Museum of Natural History 182: 1-180.
Murphy, Frances & Murphy, John: An Introduction to the Spiders of South
East Asia. Malaysian Nature Society, Kuala Lumpur.
Tso, I.; Haupt, J. & Zhu, M.: The trapdoor spider family Ctenizidae from
Taiwan. The Raffles Bulletin of Zoology 51(1): 25-33. PDF
Hendrixson, B.E. & Bond, J.E.: A new species of Stasimopus from the Eastern
Cape Province of South Africa, with notes on its natural history. Zootaxa
619: 1-14. PDF Platnick, Norman I.: The world spider
catalog, version 9.5. American Museum of Natural History.
External links Arizona Sonora Desert Museum, Trapdoor
Spider California Trapdoor Spider.
Jackman, John, Trapdoor Spider Platnick, N.I. 2003. World Spider
Catalog. Photos, Laos trapdoor spider