Trapdoor spider
Trapdoor spiders are a unique group of ground-dwelling arachnids known for their distinctive burrows topped with a silk-spun trapdoor. These spiders, primarily belonging to the Ctenizidae family, inhabit regions in the United States, Europe, and Central Asia, favoring warm, tropical, and subtropical climates. They construct burrows that can reach depths of up to 6 inches (15 centimeters) and use their trapdoors to ambush prey, which includes insects like crickets and grasshoppers, as well as small vertebrates. Trapdoor spiders are primarily nocturnal, waiting patiently behind their trapdoors to sense movement with their sensitive front legs.
While most species rely on their trapdoors for hunting, some may use alternative methods, such as silken wire traps or even pursuing their prey. Despite their adaptations, trapdoor spiders face threats from spider-hunting wasps that can invade their burrows. These spiders typically grow to about one inch (2.5 centimeters) long, with some larger species reaching up to 1.5 inches (4 centimeters). They exhibit a complex mating behavior, with females releasing pheromones to attract smaller males, followed by careful courtship rituals before mating. The female lays eggs in her burrow, ensuring the safety of the hatchlings, which resemble miniature adults. Trapdoor spiders can live for 5 to 20 years, showcasing a remarkable lifespan for arachnids.
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Trapdoor spider
Trapdoor spiders are called trapdoor because a door covers the top of their burrows. The door of the trapdoor spider burrow is spun of spider silk and is used to cover the trapdoor spider while it waits for unsuspecting animals. The trapdoor spider then springs from beneath its cover and snatches its victim.
Kingdom: Animalia
Phylum: Arthropoda
Class: Arachnida
Order: Araneae
Family: Ctenizidae
Genus: Various (see below)
Species: Various (see below)
Though spiders in the Ctenizidae family are all trapdoor spiders, species in other families, like the Actinopodidae, Antrodiaetidae, and Migidae families, are sometimes called trapdoor. The best-known species belong to the genus Ctenizid. They live in the United States, Europe, and Central Asia.
Trapdoor spiders are found in climates with tropical, subtropical, and warm temperatures. These ground-dwelling spiders burrow up to 6 inches (15 centimeters) deep in the soil. Most species build a silken trapdoor at the top of each burrow. This door is used to deceive insects and other small creatures. During the day, the spider rests, but at night, it waits behind the door with only its sensitive front legs visible. Trapdoor spiders eat crickets, grasshoppers, small fish, frogs, and ants. When an unsuspecting insect crawls by, the spider’s front claws sense movement. It quickly springs from behind the trapdoor to grab its prey. Most trapdoor spiders use this method of catching prey, but some use other traps, such as silken wire traps. Some trapdoor spiders with good eyesight pursue their prey rather than building trapdoors.
Despite their protective burrows, trapdoor spiders are often threatened by spider-hunting wasps. A spider-hunting wasp can flip open the trapdoor, stun the spider, and carry it to the nest of its young. Once the first spider is in the nest, the spider-hunting wasp lays its egg. It then travels to find more spiders for the larval young wasp, or grub, to feed on when it hatches from its egg.
Most trapdoor spiders grow to be about one inch (2 1/2 centimeters) long, but some reach 1 1/2 inches (4 centimeters). Like other spiders, their bodies are divided into two main parts—cephalothorax and abdomen. The cephalothorax is the combined term for the head and thorax, or mid-body section. All eight legs of the trapdoor spider extend from this body part. This part is sometimes also called the prosoma. The abdomen is the lower body section. It contains most of the internal organs of the trapdoor spider. It is also known as the opisthosoma. It also has a front pair of appendages called palps. The palps are used as sensory organs and for tearing and grasping. Between the palps, trapdoor spiders have large fangs. They use their fangs for piercing, crushing, and digging. The trapdoor spider also has four small, simple eyes.
Mating between trapdoor spiders occurs in the summer in temperate regions and year-round in tropical areas. Mating begins with the female trapdoor spider releasing pheromones, or mating chemical signals, into her surroundings. The male responds to the pheromones. The male trapdoor spider must carefully approach the female because he is much smaller than her and may be mistaken for food. Sometimes the male dances with the female before mating.
After mating, the female lays her fertilized eggs in her burrow. The eggs are wrapped in a cocoon and attached to the lining of the burrow. The hatchlings, or young trapdoor spiders, look like miniature versions of their parents and remain with their mothers for several weeks.
Trapdoor spiders have an average life span of between 5 and 20 years.
Species include:
Armored or spiny trapdoor spiders Idiopidae (family)
Brushed trapdoor spiders Barychelidae (family)
Folding trapdoor spiders Antrodiaetidae (family)
Sydney brown trapdoor spider Arbanitis rapax
Tree-stem trapdoor spider Aganippe castellum
Tree trapdoor spiders Migidae (family)
Bibliography
"Trapdoor Spiders." Australian Museum, 27 July 2022, australian.museum/learn/animals/spiders/trapdoor-spiders-group. Accessed 15 May 2024.
"Trapdoor Spiders." ArthropodMuseum, arthropod.uark.edu/trapdoor-spider. Accessed 15 May 2024.
"What Is a Trap Door Spider?" U.S. Pest Protection, 12 July 2021, uspest.com/blog/what-is-a-trap-door-spider. Accessed 15 May 2024.