Phidippus audax - aka Bold Jumping Spider (Family: Salticidae)

"Saltids are the most common biting spider in the United States" - Arthur Huntley MD
"Could you ever call a spider 'cute'?" - www.spiderroom.info


Yes. It was a cute spider. Even as it sat on my freshly-laundered shirt, I could see it was a beauty, with its startling black-and-white colouring, greenish mandibles and bright eyes. The tiny hairs on its front legs added to the pettable fuzziness. Of course, as with so many of Mother Nature's beauties, there is a beastly side.

Part of that beastliness had attracted my attention in the first place. It's not exactly a giant among spiders (at ½ inch long, it's large for a jumping spider) - what it is, is fast. Really very quick indeed - it seems to move from one place to another in exactly the way that spiders shouldn't, almost instantaneously. That is, in fact, how it hunts, by leaping on its prey rather than the more sedate method of catching it in a web.

It lives a fairly quiet life in forests, grasslands and gardens, across a lot of the non-tropical United States. In fact, it's the most commonly encountered jumping spider, and one of the more interesting. So before you squish it, here are a few facts to keep you occupied.

Eight of Everything

Okay, maybe not eight of everything, but it does have eight strong legs and eight bright eyes. Being a proactive hunter, it relies on sight rather than feel, and unlike our meagre spectroscopic vision, has eyes on its face as well as the top of its head. The largest pair, in the front, apparently have the keenest, sharpest vision, and the remainder give it a more general, peripheral view. Rather than having adjustable lenses as mammals do, it focuses by moving the retina, and because of this, its eyes appear to change colour as you watch it - and when its eyes are at their darkest, you are looking into its eyes as it is looking right back at you!

We do have one visual advantage though - whereas we see three primary colours, they see mostly greens and ultraviolet, which explains the iridescent green colouration of their mouthparts, and other body markings (useful at mating time, for identification). Speaking of colour, how do you recognise them? Well, the bodies of these pretty beasts are mostly black, with small, well-defined white spots and marks on the top of the abdomen.

Although they don't spin webs, they do use silk for constructing shelters under leaf litter or woodland debris, and also for use as a tether when they are hunting. But "daring"? Yes, they are audacious: their modus operandum is to sit on a branch, twig or plant and dart out at a passing insect - and while they are highly successful, they have been known to miss, and that's when their silken rope comes in handy - they simply reel themselves back in, and they are back to their preferred hunting perch. This is quite important when you consider that their long-jumping ability enables them to jump a massive two feet (60cm) - fifty times their height. Strong legs, indeed.

They mate in the spring, the females lay their eggs in silk-bound egg sacs under the bark of trees or logs in the summer, and the spiderlings hatch in autumn, to overwinter as subadults, before mating the following spring.

Beware the Bites of March

They are rarely found indoors - if they are, they are mostly to be found on windowsills or near doorways, or in places where there is a lot of cover. Mine was in the garage, hiding in the clutter on a sill next to the washing machine, and when I disturbed it, it jumped, missed me and landed on the pile of laundry.

I was lucky - according to an article by Arthur Huntley (Dermatology Online Journal 3(2): 5), they are also in the family of the most common biting spiders in the US. In the domestic environment, they are most often found in the garden, in exactly the sorts of places gardeners are likely to disturb. Their response is quick and simple - they pounce onto exposed skin and bite down. Whilst the bite is not terribly dangerous to humans, it can nevertheless be quite painful, leaving a small lump or weal, but there's no serious damage, unlike the dreaded brown recluse or black widow spiders.

This is not to say that they are not welcome creatures in the human sphere - organic gardeners and farmers welcome them as predators of many of their crop pests, both major and minor. Boll weevils, spotted cucumber beetles, bollworms, cotton leaf worm, fall webworm, cotton fleahopper, lygus bugs, stink bugs, three-cornered alfalfa hoppers, leafhoppers, sorghum midges, mosquitoes, all fall as prey under the lightning-quick dash of this daring little hunter.


Encyclopædia Britannica
http://www.spiderroom.info/va_jumpingspider.html
http://dermatology.cdlib.org/DOJvol3num2/centerfold/phidippus.html
Photo at http://www.wertperch.co.uk/gallery/view_photo.php?set_albumName=postcards&id=hn_spider_id

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