California Trapdoor Spider: Male Spiders emerge with the rain

bugman

October 15th, 2009 at 9:17 am

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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

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).”