Arachnologists at the Smithsonian National Museum of Natural History uncovered a surprising trick scorpions use to toughen their weapons. They found that some of the planet’s most fearsome arachnids reinforce their pincers and stingers with heavy metals.
These arachnids (Arachnida) reinforce their weapons — their pincers and stingers — with heavy metals, including:
- zinc
- manganese
- iron
Real metalheads: scorpions harden their weapons with metals
Scientists examined the stingers and pincers of 18 scorpion species using X-ray analysis and electron microscopy. The team also investigated which body parts accumulate which metals.
They found that zinc often concentrates at the tip of the stinger, with manganese appearing further along its length.
In the pincers, zinc and iron are most often located along the inner surface of the cutting edge. That placement helps the weapons withstand heavy loads when gripping and crushing prey.
Higher zinc content in the pincers usually correlated with lower zinc content in the stinger, and vice versa.
“Microscopic analysis methods helped us identify individual metals with extraordinary precision and see how nature skillfully integrated them into the scorpion’s weapons,” said Edward Vichenzi, a research associate at the Smithsonian National Museum of Natural History.
Although scorpions share the same basic body plan, different species prioritize different weapons. For example, members of the genus Opistophthalmus have a pair of powerful pincers and a fairly unremarkable tail. Those scorpions rely more on crushing prey with their pincers and use the stinger mainly as an auxiliary tool.
Meanwhile, members of the genus Parabuthus, aptly called fat-tailed scorpions, hunt with a massive tail that delivers fast-acting venom, while their tiny pincers are less important.
One might assume that larger pincers would be reinforced with more metal than smaller ones. The team tested that hypothesis, but the reality proved more complicated.
The analysis showed that species with longer pincers and lower crushing force had pincers richer in zinc. That pattern makes sense.
“This points to zinc’s role in providing not just hardness but, above all, strength,” said Sam Campbell, an evolutionary biologist at the University of Queensland in Australia. “Long pincers are needed to grab prey and keep it from escaping before injecting venom. This finding implies an evolutionary link between how a weapon is used and the specific properties of the metal that reinforces it,” Campbell added.
The results were published in the Journal of the Royal Society Interface.
