Some Spiders Weave Poisonous Webs

EnolaGaia

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Predatory spiders are known for using their venom to disable or kill their captured prey. Newly published research seems to have confirmed a veteran researcher's suspicion that some spiders' webs are also laced with toxins that aid in neutralizing new prey.

Some spiders may spin poisonous webs laced with neurotoxins

Droplets on the silk strands contain proteins that subdue prey, a study suggests

Orb weaver spiders are known for their big, beautiful webs. Now, researchers suggest that these webs do more than just glue a spider’s meal in place — they may also swiftly paralyze their catch.

Biochemical ecologist Mario Palma has long suspected that the webs of orb weavers — common garden spiders that build wheel-shaped webs — contain neurotoxins. “My colleagues told me, ‘You are nuts,’” says Palma, of São Paulo State University’s Institute of Biosciences in Rio Claro, Brazil. No one had found such toxins, and webs’ stickiness seemed more than sufficient for the purpose of ensnaring prey.

The idea first came to him about 25 years ago, when Palma lived near a rice plantation where orb weavers were common. He says he often saw fresh prey, like bees or flies, in the spiders’ webs, and over time, noticed the hapless animals weren’t just glued — they convulsed and stuck out their tongues, as if they’d been poisoned. If he pulled the insects free, they struggled to walk or hold up their bodies, even if the web’s owner hadn’t injected venom.

Palma had worked with neurotoxins for many years, and these odd behaviors immediately struck him as the effects of such toxins. ...

Now, thanks in large part to the work of his Ph.D. student Franciele Esteves, Palma thinks he has found those prey-paralyzing toxins. The pair and their colleagues analyzed the active genes and proteins in the silk glands of banana spiders (Trichonephila clavipes) — a kind of orb weaver — and found proteins resembling known neurotoxins. The neurotoxins may make the webs paralytic traps, the team reports online June 15 in the Journal of Proteome Research. The prey-catching webs of other species probably have similar neurotoxins, Palma says.

FULL STORY:
https://www.sciencenews.org/article/spiders-poisonous-webs-neuro-toxins-genes

PUBLISHED RESEARCH PAPER:
https://pubs.acs.org/doi/10.1021/acs.jproteome.0c00086
 

EnolaGaia

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AlchoPwn

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Some spiders may spin poisonous webs laced with neurotoxins
I have a colony of orb weavers in my garden. They keep the mosquitoes and flies down. August is feast time for them and their webs are everywhere atm. I generally roam the yard with a hand in front of my face when I wander the garden as walking into webs is unpleasant, especially at night. Their webs are seemingly thicker and stickier than those of other spiders. I wonder if that's due to the neurotoxin? I have no idea if it is the same species of orb weaver in my yard as is featured in the article. Folklore has it that they are money spiders, so I never kill them.
 

Frideswide

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Are neurotoxins specific? or do they work on anything?
 

Bad Bungle

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Are neurotoxins specific? or do they work on anything?
Astute question. Spider toxins were all the rage in the pharmacology journals 30 years ago (the chemical structures are beautiful). I remember several papers on the action of Orb spider venom on the neuro-muscular junction in lobsters. As lobsters are not considered the usual prey of Orb spiders, the significance of the results (not the pharmacology itself) was questioned by other Researchers.
 

EnolaGaia

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Are neurotoxins specific? or do they work on anything?
Any compound or substance that induces disruption, dysfunction or destruction in a given organism's nervous system and / or neural functions qualifies as a neurotoxin. As a result, a neurotoxin's target-specificity (or target-universality) depends on how narrowly or widely the affected neural components or processes are distributed.

It's not the case that all nervous systems rely upon a single precisely defined set of biochemical elements. By the same token, it's not the case that each species' neural functions are performed in a manner unique to that species. Some things generalize across species, whereas others don't.

It's probably important to note that the published research specifies a combination of fatty acids and proteins in the apparently toxic web coating. The proteins seem to be the neurotoxic element in this combination of ingredients.

These proteins aren't clearly identified in the published reports, and their mode of toxic effect isn't clearly explained. It remains unclear whether the apparent toxicity spans the given spider species' range of prey. It's also unclear whether the proteins are a natural by-product of the spider's silk generation processes.

It seems to me there's much left to learn about this newly demonstrated web silk neurotoxicity.

For example ... As far as I know protein toxins are most typically generated by microbes and plants. Is there a chance the neurotoxic proteins are being generated by parasitic microbes (on / in the spider) rather than the spider itself?
 

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I'm sure my son would just grumble that it's another reason not to trust the little bar stewards...
 
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