Posted on 10/19/2005 8:42:55 PM PDT by Mo1
Eh?
Did you know, Madame de Pompadour (December 29, 1721 - April 15, 1764) was the famous mistress of King Louis XV of France? She was born Jeanne-Antoinette Poisson.
Now, coincidentally, if you know anything about probability and statistics, the Poisson distribution is a very useful approximate distribution for counting arrival times. Especially in discrete event simulation.
(All roads lead back to Rome... Makes me feel like I should get back to work sometime... LOL!)
Oct. 28, 2005 Like the character Count Dracula and his real-life vampire bat counterparts, a small, East African jumping spider has a taste for blood, according to a recent study.
The spider, Evarcha culicivora, lacks the ability to pierce skin and to sip blood, so instead it feeds indirectly on blood by choosing, as its preferred meal, female mosquitoes that have just engorged themselves with a victim's blood.
The blood-hungry spider is the first predator ever identified that selects its prey based upon what the prey just ate. Similar to a protein shake, blood can be a highly nutritious drink that goes down smoothly.
"Perhaps blood is a ready-made nutrient-rich liquid meal for which minimal energy expenditure in terms of processing is needed," said Ximena Nelson, lead author of the study, published in a recent Proceedings of the National Academy of Sciences.
Nelson, a scientist at Macquarie University in Australia, and her team conducted a food preference test with Evarcha culicivora serving as the critic. They first put the spider in a glass vial so that it could not smell prey choices, which were a mixture of male mosquitoes that do not consume blood, female mosquitoes fed a sugar concoction and female mosquitoes that had just feasted on blood.
Using sight alone, the spider always chose the blood-engorged females, who looked fat and somewhat red.
The researchers next pumped odors of the mosquitoes into a test chamber that the spider entered. The spider, using only its weak sense of smell, went for the females that had just dined on blood.
Nelson told Discovery News that feeding on blood is a dangerous activity, so this spider appears to minimize its risk.
"Animals that are bitten have a reflective 'swatting' response humans use their arms, tailed animals use their tails, etc. and often the insect is killed," Nelson explained. "It may be safer for Evarcha to obtain blood by killing a mosquito, then risk being swatted, even if they did have the mouth parts required to pierce skin and locate a blood vessel."
The spider also uses a rather clever technique for catching its fat female mosquitoes. The spider stalks the mosquito like a cat, and then pounces either on top or underneath the mosquito before taking a bite.
With such a hunger for blood, evolution would seem to favor this spider gaining the ability to directly suck blood from victims, but Nelson thinks the way Evarcha holds its fangs might prevent this from happening.
"They hold them close to their face, not forward projecting as mosquitoes do," she said. "Perhaps they might stab themselves, and this would kill them as spiders rely on a high hydrostatic pressure inside their bodies to 'hold them up.'"
The spider, then, would sort of burst like a holiday parade balloon that has hit a pointy light post.
Steve Heydon, senior scientist and collection manager for the Bohart Museum of Entomology at the University of California at Davis, was surprised to hear of the discovery.
"I know of parasitic wasps that find their caterpillar prey based on the smell of the caterpillar's feces, but I'd never heard of a spider like this before," Heydon told Discovery News. "Spiders don't have much sense of smell, so that part of the study is especially surprising."
Heydon agrees with Nelson that spiders now probably lack the right body parts and structure to evolve into direct bloodsuckers, but he does not completely rule this out for the distant future.
"Maybe spiders will end up like bed bugs," he said. "They could have that bed-bug lifestyle of laying around and coming out at night when a big, huge, monstrous food item comes tantalizingly near them and simply goes to sleep."
Here is my lunch pic for today.
You are scary artist gran, even the pumpkin looks malevolent.
Have a great Halloween party this evening.
Nope, not even close. It's the simple thrill of knowing there are a few who think they could muster the strength to catch and kabob the shark...........when in reality.............it's like catching bubbles on the reef.......did I mention the silly stick and box traps don't work there?
:-)
No fear here.......
Nice picture! Warm sounds so good. Even though it was bright and sunny out here in the NW today, it is still soooo cold and damp.
Where'd you get the nekkid picture of Darks?
Cute, Grannie,
Verri Verri Cute.
Looks like an episode of Myst ... My daughter wants -- I think it is --- Myst 5, due out about Christmas.
Yummm....ham and cabbage (cooked just right) are 2 of my favorite things.
ears still ringing...
Ringing from what?
My darling son and I made a dry ice bomb...
Oooookay.
.....Westy.....
I took a pic of these young people as they passed by, but I was rather late getting the camera to take a better shot. I had to use zoom and crop
I thought they looked so colorful on this wet day and a good example of youth and energy to start the day for us old ones.
Dang, Sharky - I'm late to the party!!
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