A Colombian scorpion that is new to science can spray venom from its stinger to hit something up to 35 centimetres away rather than always having to inject it. The tactic is thought to be a way of defending against would-be predators.
It isn鈥檛 known what effect the venom has when it gets into an animal鈥檚 eye, mouth or nose, says , who made the discovery while at Harvard University.
鈥淏ut a fair guess is that this is going to cause some irritation and pain,鈥� he says. 鈥淚t鈥檚 probably not too serious, but definitely something you don鈥檛 want to mess with.鈥�
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The discovery was serendipitous. While at a research station in central Colombia, Laborieux set out to trap and study moths with a visiting researcher. When that failed, they caught some scorpions instead and gently prodded one with a stick to examine its defensive behaviour.
鈥淭hen I noticed this weird line of small droplets on the side of the cup,鈥� says Laborieux. 鈥淭he thought occurred to me that it could be venom spraying, but I didn鈥檛 really believe it.鈥�
Back in the lab, however, videos confirmed that the scorpions do indeed spray venom from the stinger on their tails when threatened. The animals also turned out to be a new species, now named Tityus achilles.
The spray usually consists of a clear liquid known as prevenom, which is less concentrated than normal venom. Other scorpions make prevenom, but T. achilles seems to produce more of it.
Laborieux filmed the scorpions spraying many droplets at once, but also recorded them flicking single drops from the stinger on their tail. He thinks this latter tactic might be a way for them to defend against predators like rodents while using less venom than spraying, if the behaviour is intentional.
The southern African species as a defensive measure, says Laborieux. That species is sometimes inaccurately called the spitting scorpion, in reference to聽spitting cobras.
There are reports of a few other species spraying venom too, but they are either unconfirmed or seem to be instances of very rare behaviour rather than a routine defence mechanism.
In one case, a person had temporary blindness after being sprayed in the eye by P. transvaalicus, but spraying isn鈥檛 usually a threat to people.聽鈥淭he only way to trigger this response is to actually touch the scorpion,鈥� says Laborieux. 鈥淭hey are not out there to get you.鈥�
Zoological Journal of the Linnean Society
