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Saturday, August 16, 2014

Some Spiders of Cuyamaca Woods

I periodically write a natural history-related article for our community newsletter, and just completed one on spiders, so thought I'd reproduce the article here...for the pleasure of those spider people out there!

"A Guide to (Some) of the Spiders of Cuyamaca Woods"

I know the small, many-legged ones are not everyone's favorites, but there ARE many fascinating spiders sharing our world here in Cuyamaca Woods - too many to ignore!

If you've lived here for any length of time, there's a good chance you've seen the larger, more dramatic species. The largest spider by far that we have here in the Woods is the tarantula, of course. Usually we see a small number (less than half a dozen) of the "common" tarantula of the area every year, which is a long, lanky, very dark-colored member of the genus Aphonopelma. Tarantulas are not deadly, but can deliver a bite with an intensity reminiscent of a bee or wasp sting. They also possess urticating (irritating) hairs on the tops of their abdomens which come off easily and can lodge in sensitive skin areas, causing a certain amount of discomfort to the victim. So it is not recommended that tarantulas be picked up or played with, despite the temptation for some. Tarantulas breed in the fall, so are sometimes seen in greater numbers in late summer leading into that breeding season (at least that is the pattern that I have tended to see). Watch out for them on the roads as they are slow-movers!

 Tarantula on my property, with my finger to provide scale. July 2012.
  
Another large spider species which is a regular visitor to my patio in the summer, is the Giant Crab Spider, Olios giganteus. The body length of this spider can reach around one inch, with a leg span of around 3 inches, and it is quite hairy, so it is an attention-grabber! These spiders are fairly docile (as most spiders are) and are not dangerous to humans, even if one were to be bitten by one.

 A full-sized Olios giganteus found by my neighbors right after we moved to Cuyamaca Woods.
Most residents of the Woods are all too aware of the fact that we share the neighborhood with black widow spiders. There are two possible species that could occur in our region, the Western Black Widow (Latrodectus hesperus) and the Southern Black Widow (Latrodectus mactans). The female Southern has a small red spot above the spinnerets (the "rear end") which the Western lacks. Both females possess the characteristic reddish hourglass marking on the underside of the abdomen. Black widow spider venom is a potent neurotoxin, and anyone bitten should seek immediate medical attention, and if possible, collect the spider which delivered the bite. We also have Brown Widows, which have somewhat recently been detected in California. Unlike the previous two widow species, which are native to our area, the Brown Widow is non-native, and has a range that seems to be expanding in the United States. The Brown Widow's venom is not considered to be dangerous to humans, although care is recommended around any widow-like spider encountered!

A Western Black Widow, outside my house.
A male Brown Widow on my property. Note the pale hourglass marking, and the enlarged pedipalps (the large ball-like structures at the head-end - they are used by the male to help transfer sperm to the female during mating).

The last spiders I'll mention here are very small, but bursting with personality (and energy). They are the jumping spiders - VERY aptly named little arachnids, which will leap away at the slightest provocation, but if approached slowly and quietly can be observed closely. A jumping spider will very obviously be observing you, as well, with its eight eyes, the four in the front being large, round and shiny, and thus hard to miss. The other eyes are smaller and, when combined with the anterior ("front") eyes, give a jumping spider close to a 360 degree range of vision!

The jumping spider family (Salticidae) is the largest spider family, and for those who are motivated, finding species in Cuyamaca Woods could probably become a full-time hobby (if one chose!). I am slowly trying to photograph jumping spiders as I encounter them in the area, and have encountered the common kinds, which are usually in the genus Phidippus, as well as one which may be an undescribed species - time will tell, and a jumping spider expert has a single specimen of the "mystery" spider.

A colorful jumping spider, Phidippus sp. just outside the house.

For those interested in seeing a few more Cuyamaca Woods spiders (including the "mystery" jumper mentioned above, labeled "Maevia") and other arachnids, see: https://www.flickr.com/photos/39935474@N03/sets/72157646520448242/

These are by no means the only spiders in Cuyamaca Woods - just a tiny cross section of some of the more conspicuous or charismatic. We seem to live in a very rich environment with many species, so keep an eye out for other intriguing eight-legged ones as you go about your business or pleasure in the Woods.

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