The Secret Behind the Scorpions’ Lethal Arsenal? The Metal

Recent analyses have helped clarify the composition of the metallic alloy that underpins the remarkable durability of the pincers and stingers across many scorpion species.

A New Light

Alongside Komodo dragons (Varanus komodoensis), scorpions are arguably among the most iconic creatures known to rely on such a strategy. If large concentrations of metals strengthen the former’s teeth, they also help protect the lethal weapons of these arachnids.

Although the areas involved in this second case are often detectable to the naked eye, Sam Campbell, from the University of Queensland, and his colleagues used a range of imaging techniques, including radiography and electron microscopy, to delineate the extent of these protections and their composition.

Published in the Journal of the Royal Society Interface and covering 18 species of scorpions, their work reveals three main elements (iron, zinc and manganese), to which copper, nickel, silicon, chlorine, titanium and bromine are added.

« They are concentrated at the tip of their stings, along the edge of their pincers, as well as in their mouthparts and tarsal segments », notes Campbell. « The rest of their exoskeleton is comparatively much more flexible. In some respects, one could compare them to safety footwear with reinforced toes. »

A Likely Reflection of Their Way of Life

It has also emerged that the placement of the reinforcements and their concentrations of metals varied significantly from one species to another, a probable reflection of their lifestyle. “When zinc content was high in the pincers, it was low at the stinger, and vice versa,” details Campbell. “Given that these arachnids employ a variety of predation techniques, it is likely that this composition provides distinct biomechanical benefits.”

At this stage, precisely how the scorpions obtain these reinforcing elements for key body parts remains unknown, but their prey appears to be the most obvious source.

According to Aaron LeBlanc of King’s College London, the next step will be to determine how this trait evolved across the major animal lineages. “A growing number of studies show that it also concerns the teeth of many vertebrates,” he notes.

Some years ago, researchers had uncovered the secret of the metal fangs of a terrifying marine worm.