What's That Bug? does not endorse extermination

2 inch black spider with brown abdomen
October 15, 2009
This spider crawled over my wife’s foot. It’s about 2 inches long, shiny black with a brown slightly furry abdomen. It’s mid October here in LA and we just had a rather large rainstorm, the first of the season, possibly it tried to escape into the house? We let him go right after we took the picture.
Syd
Los Angeles California

Male California Trapdoor Spider

Male California Trapdoor Spider

Hi Syd,
This is a male California Trapdoor Spider, Bothriocyrtum californicum
.  Each year, the first rains of the season trigger the mating instinct of the male California Trapdoor Spider who leaves his burrow and wanders in search of a mate.  This species is sexually dimorphic.  Sadly, the male spiders often wander into backyard swimming pools and drown.  Interestingly, our Mount Washington Los Angeles neighbor Jeanie left a tupperware on our porch last night.  There is a male California Trapdoor Spider in that tupperware.  We were waiting for morning light to take our own photo to create a posting.  According to Charles Hogue, in his awesome Insects of the Los Angeles Basin, “Trapdoor spiders are novelties in the Los Angeles Basin today, although they were commonplace a few years ago.  They were even collected and sold as curios in the Los Angeles area at the beginning of the twentieth century.  Their rarity now is another example of human expansion destroying the habitat of a local animal.  The spider prefers to build its nest on sunny south-facing dry hillsides, which in the spring bear a thick covering of short grasses and low herbs.  Such areas are becoming increasingly rare in the basin (they are also the habitat of our local tarantulas, and both types of spiders can be found living on the same hillsides).”

Male California Trapdoor Spider

Male California Trapdoor Spider

What's That Bug? does not endorse extermination

23 Responses to California Trapdoor Spider: Male Spiders emerge with the rain

  1. l-dub says:

    I just had one of these crawl out of my shower drain while i was taking a shower. scared me half to death! i decided to look online to see what it was…im glad its not poisonous!

  2. dobefoto says:

    I live in Silver Lake (LA) & found one floating in my pond this morning. I thought it was dead, and removed it to photograph it. A couple hours later, it started walking away! Checking online, I see it’s definitely a CA Trapdoor Spider. I will release it in the vacant lot next door.

    • bugman says:

      Since Southern California is bracing for a five day storm predicted to be the worst in a decade, we hope your rescued California Trapdoor Spider manages to find a safe retreat.

  3. The type locality of the trapdoor Bothriocrytum californicum is Inglewood, CA. I observed trapdoors for years. Their doors can open in any direction, they were once abundant on flat ground, without plant cover, directly across the street from my Inglewood home. A Newport Bay report stated that their burrows were vertical. Actually their burrows are gently curved in an “S”- shape expanding at the ending–none are actually vertical.

    • bugman says:

      Dear John,
      Thank you so much for your firsthand knowledge of California Trapdoor Spiders, a truly magnificent species. We are saddened that their numbers are dwindling due to habitat loss.

  4. Garry says:

    Hey Guys,

    I just had a CA TDSpider try to hide in my shirt collar. I found him when getting ready for work. I live in Pacific Grove, CA and was scared it was a Brown Recluse. Glad you all had pic posted here!

    • bugman says:

      Did you forget to hang up your clothes? We don’t believe a California Trapdoor Spider would climb into the closet and settle into the clothes on hangers, or even the clothes in drawers, but clothes left on the ground might provide a secure resting place.

  5. Misty says:

    I found a California trapdoor spider on the bottom of my stairs on the way to my laundry room…He looked dead ants were on him but it didn’t look like they were eating him! I flipped him periodically through out the day to take pictures, Finally I felt so sad to see the ants surrounding my husband got a paper and through him on the hillside, Reading up on him, I wonder why he left his trap to die? It was raining the prior day although that was a weird spot for him to pass on! He was beautiful!

  6. chantell says:

    My mom and i found two of these in a tarp puddle and we have never seen them before. I thought they were dead but i was so wrong..i read up on these spiders and im curious, what are they in eugene oregon for if they are meant to be in warm weather? Theres no sign anywhere where we live of their nests either

    • bugman says:

      Without an image, we are unable to comment on the spiders you encountered. There are species of Trapdoor Spiders in Oregon, and though BugGuide does not report any sightings of California Trapdoor Spiders outside of California, it is possible that the range is greater than what is reported.

  7. Tony says:

    We have a very large black trap door spider in the back yard. (GA) What is it?

  8. Tony says:

    he or she is completely black.

  9. john says:

    Very common up here in the California San Bernardino Mountains, We even had a good sized female build a home under our bathroom sink… (she was relocated) Folks up here are constantly posting pics of the CTDS on local FB pages asking what they are…so I educate them when I can…

  10. Ray Sicko says:

    I found a CTD spider in Lakeside CA at Walmart in the parking lot right after hard rain then drizzled ..this guy( CTD spider )was walking in the parking lot I scooped him up brought him home and I will release him on the mountain side I live by so hopefully he can mate and live on….

    • bugman says:

      It is our experience that many large insects meet cruel fates in parking lots. Stomping feet tend to do more damage than getting run over by cars. Your actions may have saved the life of a Trapdoor Spider.

  11. Emily says:

    Oh my goodness, feel so bad! Last night we came across 5 of them and killed them, they were so scary looking I thought they were deadly! So glad I looked them up, at least now I know. Last night I searched online but nothing came up.

    • bugman says:

      Finding so many after a good rain is an indication you have a healthy population. Male Trapdoor Spiders often die while searching for a mate. We hope in the future you will be more tolerant of these incredible spiders.

  12. Ashleigh says:

    One was just crawling across my bedroom floor in Highland Park (Los Angeles), it rained yesterday for the first time in ages. I have him in a big jar. Where is the best place I can release hopefully away from my house?

    • bugman says:

      You might consider the hill between Highland Park and Eagle Rock, where Avenue 51 becomes Townsend, which is Occidental College property. This is open space that will not be developed.

Leave a Reply

Your email address will not be published. Required fields are marked *