One idea the team floats is that zinc and manganese are limited resources, so scorpions can only reinforce the most critical parts of the stingers instead of spreading the metals across their entire exoskeleton.
Going deeper into the reasons behind what appears to be a design flaw in an otherwise neatly built stinger is one thing 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 from each species,” Campbell said.
The downside of this approach is that the study did not capture variations in metal-enrichment patterns between different individuals of the same species. These variations, Campbell acknowledged, may be significant in scorpions, which in general have strong sexual dimorphism—females are typically much bigger than males.
Another angle the study did not cover is whether metal enrichment changes across the scorpions’ lifespan. Scorpions undergo several molts in their lives, shedding their exoskeletons to grow and transition into a new stage, or instar. “There was a study that showed in the first instar, when the scorpion is born, there is no metal enrichment,” Campbell said. “The metal starts to come to the stingers by the second instar.”
The challenge in answering questions like these, Campbell thinks, is that scorpions are notoriously difficult to study. They are nocturnal, they often live in deserts, and they burrow underground.
“We don’t 100 percent know what their behavior is,” Campbell said. “It would be good to make true correlations between what we observe in the wild, how they interact with their environment, and what we find in their exoskeletons in the lab. That would be a huge, huge study to try.”
The team’s study on metal enrichment in scorpions’ weapons is published in the Journal of The Royal Society Interface: https://doi.org/10.1098/rsif.2025.0523