California Trapdoor (Bothriocyrtum californicum)

Get ready to learn about the spiders from the Ctenizidae family! Often called California trapdoor spiders, they live not just in California but all across the United States. These spiders have some pretty neat tricks up their sleeves.

Scientific Classification

• Family: Halonoproctidae
• Genus: Bothriocyrtum
• Scientific name: Bothriocyrtum californicum

Photo Credit: Kevin Lentz

Physical Description and Identification

Adults

• Size: Females are 1.25 inches (3.3 cm) long, while the males appear shorter, measuring 0.75 – 1 inch (1.8 – 2.6 cm).
• Color: They come in a wide range of colors, including yellow, brown, and black. These spiders even have a chocolate brown cephalothorax, pale brown abdomen, and black jaws.
• Other Characteristic Features:  They have a plump body with short and thick legs and a pear-shaped abdomen. The cephalothorax is large and round, with a dimple-like feature at the center. In contrast, their jaw or chelicerae have spiny projections.

Photo Credit: Tobi Hays

Eggs

After copulation, females lay eggs in the burrows, 7-8 inches deep. The mother takes the utmost care of her eggs, hanging them up on a silk cradle wall.

Spiderlings

After hatching, the spiderlings remain dependent on their mother for a few days, especially during the first winter. Throughout this phase, the mother feeds them. Then they leave their burrows and start building their web.

The Web

Californian trapdoor spiders do not build full-fledged webs; instead, they dig up burrows and make trap gates with their silk.

Are California Trapdoor Spiders Venomous?

Yes, California Trapdoor spiders do have venom. They use it mainly to paralyze their prey. Their venom isn’t dangerous to humans.

Can California Trapdoor Spiders Bite?

Indeed, they can! They might bite if they feel trapped or scared. It’s a good idea to observe them without touching them.

Photo Credit: Tobi Hays

Ecological Importance and Behavior of California Trapdoor Spider

California trapdoor spiders are critical ecological agents, maintaining the insect population and enriching soil quality through their burrowing activities.

Natural Predators: These spiders face predation from various animals, which plays a role in the control of their populations and the broader ecological balance.

Prey-Predator Dynamics: By hunting a variety of invertebrates, they help to regulate these populations, contributing to the ecological health of their habitats.

Relationship with Humans: Despite their venom and capacity to bite, California trapdoor spiders have a relatively peaceful coexistence with humans and can even be part of the pet trade due to their unique characteristics.

Quick Facts

Photo Credit: Jeffrey Early

Did You Know

• Female Californian trapdoor spiders never go far from their burrows.
• Due to their physical similarities, Californian trapdoor spiders often look like mini tarantulas, though they appear shinier.
• Despite their aggressive behavior, they are common in the pet trade.

Photo Credit: Tobi Hays

In summary, the California trapdoor spider is a species that showcases the marvels of nature’s engineering and the complex interplay between different organisms within an ecosystem.