Researchers from NUI Galway have shown, for the first time, that smaller scorpion species with smaller claws have more potent venoms than larger species with strong claws.
Scientists have tested the theory of Indiana Jones and the Kingdom of the Crystal Skullwho warned of the dangers of small scorpions, and that “when it comes to scorpions, the bigger the better”.
While this is merely a throwaway film line from adventurous archaeologist Indiana Jones, research shows there is some truth to it.
The team of scientists from the Ryan Institute at NUI Galway put the quip to the test by analyzing 36 species of scorpions to show that larger scorpions have less potent venoms and are actually better at avoiding a bad sting.
The research results have been published in the international journal Toxins.
It shows the smallest scorpions in their analysis, such as the Brazilian yellow scorpion, where over 100 times more powerful than the largest species they studied, such as the rock scorpion.
The potency pattern was not just in body size, but also in claw size, with venoms found in species with the smallest claws, including the South African thick-tailed scorpion, which is more than 10 times more powerful than species with the largest and sturdiest claws, such as the Israeli golden scorpion.
Dr Kevin Healy, lecturer in zoology at NUI Galway and lead author of the study, said: “Apart from the entertaining movie trivia, there are good evolutionary reasons to expect the results and the important medical implications. for such models.
The researchers pointed out that while scorpions use both their poisonous stinger and pincers to capture prey and to defend themselves, there is an evolutionary trade-off between these weapons. The energy used to make larger claws means less energy is available for its chemical arsenal. As a result, larger scorpions that can use their physical size depend less on venoms, while smaller species have evolved more potent venoms.
Dr Healy added: “When we look at the most potent and dangerous scorpion venoms, we find that they tend to be associated with species such as the deadly stalker that are relatively small. In contrast, the most large species such as rock scorpions have venoms that are likely to cause only mild pain.”
Alannah Forde, NUI Galway graduate student and lead author of the study, said: “Not only have we found that bigger is better – when it comes to people bitten – we have also found that larger claws are better when it comes to gauging a scorpion’s danger level.Although species such as the large-clawed scorpion can be small to medium in size, they rely primarily on their large claws instead of their relatively weak venom.
Scorpion stings are a global health problem with over a million cases and thousands of deaths every year. Identifying the species involved in a sting is vital to treatment, so general rules such as “bigger is better” are often used to aid in treatment.
The team aims to test these evolutionary rules of what makes certain species more powerful to help develop better medical approaches to scorpion stings.
Dr Michel Dugon, Head of the Venom System Lab at NUI Galway and lead author of the study, said: “As scientists, our job is also to put conventional wisdom to the test. Most victims hospitalized with severe symptoms from scorpion stings are children. before the age of 15. Identifying the responsible species is key to administering the right treatment, and a simple rule such as “bigger is better” is a small first step in saving lives. »