Spider Brains: A Love Story (Book One) (7 page)

I
looked over at Jamie who was looking over at Ricki who was looking over at Billy all googly-eyed. Then, Ricki looked at Jamie, who looked over at me. I shook my head and Jamie rolled her eyes and Ricki blushed.
Things seemed to be changing, and fast.

C
rowing out the words, Morlson broke my concentration.
“Due one week from today another 2000-,” ANOTHER ONE! “word essay based on research. Title your page: What kind of bite is it? Name and date.” She slammed the blue marker so hard onto the metal whiteboard shelf that the cap on its end popped off and bounced across the indoor-outdoor-commercial-grade composite tile floor like an ellipsis off the end of a straggling sentence.

She turned around slowly. Her face had pinched into what Ricki and Jamie and I call a sphincter-face. And, when she talked, it felt as if she were peering directly at me and into my soul when she said the last words just seconds before the end-of-class-bell hummed.

“
The doctors couldn’t figure out what might’ve bitten me, so, I doubt if
you
will either.” She sneered.

It felt like the biggest challenge of my life.

That night, after I snapped off a few close-up photos of my teeth, I went to sleep.

Then, I showed
her
.

Chomp! Chomp!

NINE - My Brain on Spiders

S
o, like. I never thought I would get such a dismal grade. I mean. I did
, unerringly, what Morlson instructed. I researched spider bites and put it into a report. Just like she asked.

WHAT KIND OF BITE IS IT?

by Susie Speider

November 1, 2010

A spider bite happens when a spider, or other closely related arachnids, bites you.

Spiders are very active hunters. Which makes them very scary to me. They rely strongly on biting to paralyze and kill their prey before consuming them. Yikes. Since spiders are aware of the effect caused by their bites, they also bite to fend off intruders who might be risking damage to their homes, like, their cobwebs.

While many spiders never attack animals larger than themselves (preferring to run away or feign death), some will exhibit rather aggressive behavior and do so even if no real danger exists.

Eek! A creepy trait, if ever.

Only a minority of spider species possess chelicera--FANGS!-- strong enough to penetrate human skin, however due to their strong survival instincts, the ones with the strong fangs are the ones most frequently encountered by humans. Coincidence? I think not. And. Double EEK!

However. About 98% of bites inflicted by these strong-toothed creatures are harmless, but some symptoms can include necrotic wounds (dead tissue... pee-U), systemic toxicity (swelling and itchiness) and, in some cases, death. And, you know what that means--Bye Bye Birdie!

Which makes me wonder why they include this deadly population of spiders in this section of the 98% harmless ones. Doi.

There exist two hundred species in twenty genera (out of, like, over 40,000 known spider species) that are known to have serious, potentially lethal bites.

For most bites, the major concern is venom. But, I'm thinking that the biting part really totally sucks (get it?). And, in some cases these seemingly non-significant spiders can even transmit infectious diseases. Kee-Rikey!

There are only three genera of spiders known to be non-venomous, because they do not possess venom glands or any proper way to deliver venom if they have venom glands. These "harmless-to-human" spiders include the families Uloboridae, Holarchaeidae and Liphistiidae. (None of which I can pronounce no matter how I've tried. I think it's my braces.)

These spiders, however, do possess fangs and can deliver sharp, unpleasant bites. In addition, the fangs of Liphistiidae can often inflict infections spread through the skin, mostly due to their large size, which in theory could represent more of a danger than the bite of a non-lethal venomous spider. Shiver & shake!

Spider bites may be misdiagnosed by both the general public, like me, and medical practitioners. So it's probably wise to find a spider expert to diagnose your bite if you find your leg beginning to fall off.

The primary concern of the bite of a spider is the effect of its venom. I think we established this earlier however it is reiterated here so that we can get back onto the venom track. A spider
envenomation
occurs whenever a spider injects venom into the skin. Not all spider bites involve envenomation. Plus, the amount of venom injected can vary widely based on the type of spider and the circumstances of the spider encounter. With very few exceptions (such as the so-called camel spider which, btw, is not a true spider nor is it a true camel), the mechanical injury from a spider bite is not a serious concern for humans.

Some spider bites DO leave a large enough wound that infection may be a concern, and other species are known to consume their prey which is already dead and you know how big a spider would have to be to consume and entire human being, even a baby? That's one big spider. I mean.

However, it is generally the toxicity of spider venom which possesses the most risk to human beings and, this is the real gruesome part of my essay--several spiders are known to have venom which can be fatal to humans in the amounts that a spider will typically inject when biting. Holy.

Still, all spiders are capable of producing venom, with the exception of the hackled orb-weavers which we find mostly in the fall. Their scientific name is the Holarchaeidae, and the primitive Mesothelae. These spiders get big and round, hence earning their name "Orb Spiders." Other arachnids often confused with spiders, such as the
harvestman
and
sun spiders
, also do not produce venom. And, that's good to know. They get their names, Harvester & Sun Spider we assume because they harvest by night and bask in the sun by day.

Nonetheless, only a small percentage of species have bites which pose a danger to people. And, while 'venoms' are by definition toxic substances, most spiders do not have venom which is sufficiently toxic in the quantities delivered, to require medical attention, and, for those that do, only a few are known to produce fatalities. Dum da da da DUM!

Spider venoms work on one of two fundamental principles--they are either neurotoxic meaning they attack the nervous system; or, they are necrotic meaning they attack the tissue surrounding the bite. In some cases, spider bites can effectively attack vital organs and systems. Causing a deadly effect if you don't get to the hospital right away.

Definition/Example: Neurotoxic venom--the majority of spiders with serious bites possess a neurotoxic venom of some sort, though the specific manner in which the nervous system is attacked varies from spider to spider.

The ever lonely Widow spider venom contains components known as latrotoxins, which cause the release of the neurotransmitter acetylcholine, stimulating muscle contractions. This can affect the body in several ways, including causing painful abdominal cramps, as well as interfering with respiration, and causing other systemic effects. We must remember to stay away from widow spiders... at all costs.

The venom of Australasian funnel-web spiders and the really cute mouse spiders work by opening up sodium channels, causing excessive neural activity which interferes with normal bodily function. Think seizure here.

The venom of Brazilian wandering spiders (a nomadic group, if ever), is also a potent neurotoxin, which attacks multiple types of ion channels. Additionally, the venom contains high levels of serotonin, making an envenomation by this species particularly painful. And, I would think causing you to stay far too awake so you might want to avoid a bite from these hideous creatures close to bed time.

Definition/Example: Necrotic venom--Spiders known to have necrotic venom are found in the family Sicariidae, a family which includes both the recluse spiders and the six-eyed sand spiders. Spiders in this family possess a known dermonecrotic agent sphingomyelinase D. I will never be able to pronounce any of that anytime soon. This agent, is found only in a few pathogenic bacteria. Some species in this family are more venomous than others. According to
one
study, the venom of the chilean recluse and several species of six-eyed sand spider indigenous to southern Africa (phew!), contains an order of magnitude more of this substance than do other Sicariidae spiders such as the brown recluse. So, if you get bit, start digging a hole big enough for a coffee can 'cause that's all that'll be left of you in no time, flat.