Some Spider Webs Are Armed With Neurotoxins To Paralyze Prey

A golden silk orb-weaver spider (Nephila clavipes) over its fiendishly evil web. Arkorn/Shutterstock

Golden silk orb-weaver spiders have got a devilishly cruel trick up their eight sleeves. New research has suggested that this species of spider loads its web with a dose of neurotoxin that slowly paralyzes its prey. 

Reported in the Journal of Proteome Research, scientists at the University of São Paulo State in Brazil discovered evidence of “toxin/neurotoxin-like proteins” on the web silk from the golden silk orb-weaver spider (Nephila clavipes). The researchers postulate that the web is not just a sticky net that the spiders use to catch their prey, but it’s also a weapon that helps to freeze their unsuspecting prey into paralysis with a cocktail of neurotoxins. 

The idea behind the research started after scientists noticed that some of the insect prey that became stuck in this species’ web quickly started acting strangely, with a trembling body, irregular walking, and sticking out their tongue. 

To investigate this oddity further, the team extracted some of the substances found on the web silk and applied different concentrations of the extract to honey bees, which are the natural prey of the golden silk orb-weaver spider. They found the animals started to move slower and slower, before becoming paralyzed.

The team also discovered that the neurotoxin-like proteins found on the web are similar to the ones found in the venom of the spider bite. However, they found that other compounds are also necessary for this attack to be so effective. 

“The chemical composition of the secretion applied by the spider over the web contains compounds that ‘remove’ the waxy protection from the body of the prey, opening the access to the neurotoxins to diffuse into the body of the preys, causing paralysis,” Professor Mario Palma, study author from the Center of the Study of Social Insects at São Paulo State University, explained to IFLScience.

“The neurotoxins may be blocking some types of neuroreceptors that control the nervous impulses to the legs of preys,” Professor Palma added. 

“These neurotoxins are not very potent, since the purpose is only to cause prey paralysis; it is important to mention that the spiders only eat alive prey. If the neurotoxins were too potent, the prey could die, and could not be eaten later by the spider,” he continued.

Fortunately, just like the bite of this species, the weakness of the venom most likely means their webs are harmless to us humans. The same can’t be said for other small insects, however. 

“We have not tested the actions against humans yet; however, considering the known chemical compositions and the tiny amounts observed under natural conditions, there will probably be no danger to humans,” concluded Palma.  

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