Bug Blog

Why A Large Scorpion Species Produces Two Types Of Venom

Some scorpion species produce venom that can potentially cause death, and surprisingly, the most deadly scorpion species are most often the smallest as well. This correlation is exemplified by the non-fatal stings dealt out by the enormous Parabuthus transvaalicus scorpion species. While this scorpion species may not kill a human with its sting, it is one of the largest scorpion species in existence, as their average length is around 5 inches. However, when considering relative venom strength between different scorpion species, the Parabuthus transvaalicus belongs in a category of its own. This is because Parabuthus transvaalicus produces two different venoms, one for pacifying enemies and the other is for exterminating enemies. So far, the Parabuthus transvaalicus is the only scorpion species that is documented as producing two entirely different types of venom.

The Parabuthus transvaalicus scorpion species is known by many names, but in its native South Africa, the species is often referred to as the “spitting scorpion.” This is an apt name, as this scorpion species can literally spray venom out of its stinger like water from a hose. Unlike any other scorpion species known to science, spitting scorpions rely on two different venoms that serve different purposes. One venom is non-toxic, but causes pain when applied to open wounds. This venom is used to deter predators that the scorpion does not plan to eat, and therefore, does not need to kill. The other venom is toxic and its used to kill prey for consumption. Since spitting scorpions dwell within dry desert regions where prey are hard to come by, they cannot afford to waste their toxic venom on animals that merely pester them; instead, the scorpions save energy by using another non-fatal venom for deterring non-threatening enemies. This non-fatal venom requires less energy to produce, making it ideal for a scorpion species that does not always have ready access to food sources.

Venom production is metabolically costly, due to the energy it takes to produce complicated venom proteins. The toxic venom produced by spitting scorpions requires a greater production of proteins than is required for the non-toxic form of venom. For example, if a mouse begins to nibble on a spitting scorpion that is not hungry, the scorpion will save its essential killer-venom by using their non-lethal but painful venom to sting the mouse. However, when a spitting scorpion becomes hungry and begins to hunt, it can make use of a full stock of fatal venom in order to effectively secure prey.

Are you curious as to how painful the non-toxic venom produced by spitting scorpions feels to humans?