Wednesday, August 31, 2011

Spider season

A small Jumping Spider (Salticidae) on a hedge near our apartment. Two of there eight eyes are stereoscopic like ours. They can judge distances and have the best vision of all spiders. They are harmless. Some species in tropical areas will bite if harassed but from personal experience the bite is not nearly as painful as a bee-sting. 99% of spiders are HARMLESS to humans and spider hysteria still grips the USA. Recently, a poor species of harmless louse spider was featured as a "brown recluse" on a news program. I was shocked but it was too late for me to say anything. They did not even have anyone on hand to identify a captured spider. The press showed it and the "bites" that the woman suffered were probably a skin condition aggravated by scratching. People get a condition or painful sore and often see a spider and that's it. It's not fair and ignorant. Without spiders, we would be knee deep in dangerous insect species, many of which carry truly deadly diseases. They way people treat spiders often reminds me of a witch hunt in the dark ages.

Another benfifical species I have featured many times, Araneus diadematus the most common species of spider in much of North America and the first species of spider known to build webs in outer space. Several of them were taken up in the Space shuttle and to the amazement of scientists they built perfect webs without gravity. Adapting by learning they soon figured it out by trail and error in this strange environment. This cast doubt on the idea that fixed programming--instinct--is the only thing even invertebrates know. They clearly can learn.

This male of the same species has his legs set on a nearby female. He will pluck out a code specific to his species letting her know he's interested and keeping her from seeing him as a meal. For this species, the male is not eaten by the female and the usually part ways without incident after mating.

The same spider from another angle.

"Hot Spider"
This spider is of the same species as those featured above. She is VERY hot. An interesting observation I have made all over the world is that many very different species of orb web building spiders change how they sit in the web on very hot days. It was about 90 F when I took this picture. They seem to attempt to get there body out of the sunlight at least to some degree by changing there posture. I am surprised she has not chosen to go to a hiding place in the shade. Maybe there is not one, or maybe since she is in need of a good meal she wants to be ready for any insect that comes by.

1 comment:

JMixx said...

Jumping spiders are so awesome! How many different species are there? I had one "move in" to my bedroom years ago. He (or she) stayed up in the corner of the ceiling while I was up and moving around (can't blame him!). At night, when getting ready to go to sleep, I would open the window and lie in my bed reading by a bedside lamp. Because of the light being on at night, tiny little "no-see-um" bugs- probably gnats--would come through the screens to get near the light. Little Jumper would scoot and spring (stalking!) from the corner of the ceiling over to the wall above the lamp. When one of the little gnat-type bugs landed, he would maneuver carefully into place on the wall a few inches higher. He would fasten the end of a silk thread to the wall, and, once he had everything worked out, he would push into his back legs, get set, and spring straight out from the wall. He had apparently spun exactly the right amount of silk for the distance, because when he reached the end of his "rope," he'd swing down and land directly on his target. If he missed, it wasn't very often. Watching him swing down onto his prey, I used to imagine him doing a tiny little Tarzan call ("Aaaaahhh-weeaaah-eeeeaaa, eee-aaa-eee-aaa!" I'm not sure how much math it would take me to calculate distance from the target, how far out I'd need to swing, and how much rope to let out, but I doubt I could do it before the gnat flew away--and the little jumping spider did it over and over.

I always imagine them having a Mexican accent, because what I take to be their mouth-parts are usually a contrasting color,covered with hairs, and look like a big handlebar mustache. With their two large, front-facing eyes, it's really easy to anthropomorphize.

I hope you don't mind me commenting; I just saw your Jumping Spider photo, and it brought back fond memories. Most spiders I can take or leave--we have mostly little ones around here, and they can do as they like as long as they don't make a habit of strolling across me while I sleep--but I really like the Jumping Spiders.