Scorpions incorporate heavy metals into their exoskeletons in different ways, depending on how they hunt and defend themselves.
The researchers detected concentrations of zinc e ferro in the clamp Leiurus quinquestriatus.
In a new one, published this Wednesday in Journal of the Royal Society Interfaceresearchers examined the stingers and pincers of 18 species of scorpions using X-rays and electron microscopes. Then they analyzed where metals like zinco ferro and the manganese they were being enriched.
According to , scientists observed that zinc is often concentrated at the tip of the stinger, while manganese becomes the predominant metal further down the length.
In pincers, zinc and iron appear most frequently along the inner surface of the blade, helping it withstand the tension of grasping and crushing prey.
These patterns were not generally found in the same species. Higher levels of zinc in the pincers typically meant lower levels in the stinger, and vice versa.
“The microscopic-scale methods we used allowed us to identify individual transition metals at an extremely high level of detail, showing us how nature cleverly designed these metals into the scorpion’s weapons,” said study co-author, Edward Vicenzi.
Although scorpions generally follow the same body plan, different species prioritize different weapons. The genre Opistophthalmusfor example, has a pair of powerful pincers but a rather modest tail.
These scorpions use their forelimbs to dig burrows and focus more on crushing prey with their claws, using their stinger only as a secondary resource.
Those of the genre Parabuthushowever, they are not called thick-tailed scorpions for nothing. Their hindquarters deliver venom quickly, so grabbing prey is not a priority. This is quite clear from the clamps they have.
At first glance, one would expect the larger grippers to be reinforced with more metal than the smaller ones, and that was the team’s hypothesis in this study. But the results are surprising.
The analysis revealed that, in species with longer claws and less crushing power, the pincers had higher levels of zinc enrichmentcompared to those with greater force in the clamp.
“This points to a role for zinc beyond hardness, perhaps playing a more important role in durability. After all, the long claws need to grab the prey and prevent it from escaping before being bitten by the venom” says the first author of the study, Sam Campbell.
Finally, this is a study with broad implicationsnot only for scorpions, but also for other arthropods that reinforce their bodily weapons with metals, be they spider fangs, ant jaws or bee or wasp stingers.
