One idea the team has is that zinc and manganese are limited resources, so scorpions can only strengthen the most important parts of the sting rather than spreading the metals throughout their exoskeleton.
Delving deeper into the reasons for what appear to be design flaws in the otherwise cleanly built Stinger is something Campbell wants to focus on in the future. But the team thinks there’s more to learn.
“We were using museum specimens, and we only picked one of each species,” Campbell said.
The downside of this approach is that the study did not capture variation in metal-enrichment patterns between different individuals of the same species. Campbell acknowledged that these variations may be important in scorpions, which generally have strong sexual dimorphism – females are usually much larger than males.
Another aspect not included in the study is whether metal enrichment changes over the life of the scorpions. Scorpions go through several molts, shedding their exoskeleton to grow and transition to a new stage, or instar. “One study showed that when scorpions are born, there is no metal enrichment in the first stage,” Campbell said. “Metal begins to appear in the sting by the second instar.”
Campbell believes the challenge in answering such questions is that scorpions are extremely difficult to study. They are nocturnal, they often live in deserts, and they burrow underground.
“We don’t know 100 percent what his behavior is,” Campbell said. “It would be nice to make a real connection between what we see in the wild, how they interact with their environment, and what we find in their exoskeleton in the lab. It would be a very big, huge study to try.”
The team’s study on metal enrichment in the scorpions’ arms is published in the Journal of The Royal Society Interface: https://doi.org/10.1098/rsif.2025.0523
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