Critter Corner
The Preservation News. September, 1999
© 1999

by Lenny Vincent


Late autumn to early winter is the best time of year to spot our local tarantulas cruising across fire trails in the coastal sage scrub. The spiders you see are male tarantulas in search of females for mating. Local tarantulas are blackish to dark brown with bodies almost two inches long.

Males reach sexual maturity in eight to ten years. At this time of year the mature males permanently abandon their burrows to seek mates. The best time to observe these searching males is at dusk. The relatively slender, long-legged male tarantula, after finding a female's burrow, entices the stocky female out for courtship and mating. The female is larger because she stores nutrients for egg production.

Courtship, which consists of tapping the ground at a particular frequency, is designed to inform the female that the male is a potential mate and not just a meal. Courtship is also used to determine if the female is receptive to mating. If she is not, she will vigorously lunge at him and he will beat a hasty retreat. If she is receptive, she will rear back allowing him access to the genital opening on the underside of her abdomen. Mating is usually over in less than five minutes. Afterwards the female returns to her burrow while the male sets off to find another partner.

Each successful mating results in the production of an egg sac. The sac is laid deep within the burrow and may contain well over a hundred eggs. The eggs hatch in about seven weeks. Less than a month after hatching, the young spiders leave their mother's burrow to establish their own.

After their single mating season, the males die in mid-winter. Female tarantulas mate many times over their 20-30 year life span, if they are lucky enough to avoid enemies like our local tarantula hawk. This 'hawk' is actually an extremely large metallic-blue wasp that sports rusty-orange wings and a nasty sting.

A word of caution:

The bite of our local tarantula is normally harmless; the pain has been equated to that of a bee sting. They should be handled with care, however, since they have barbed hairs on their back side. These urticating (stinging) hairs, which are kicked off by the spider using their hind legs, are extremely light and can be carried, by even very weak air currents, to the eye where they can cause a significant irritation.

Next time: The tarantula hawk

Lenny Vincent teaches biology at Fullerton College and is on the Board of Directors of the Laguna Greenbelt, Inc.