Recent research has solved the mystery of one of the most amazing phenomena in the animal world – moths with metal teeth. Cross a moth, and you may be in for a nasty surprise. Stretching up to 35 centimeters (14 inches) in length, their narrow bodies and fleshy pink coloration may not make them look so threatening, but their metal teeth tell a different story.
Bait fishers and fishermen are likely to be victims of a moth bite, and reports from those who have experienced it for themselves paint an ugly picture. Perhaps this is not surprising, given that moths can bite through the exoskeleton of their prey and inject venom to paralyze them. It is even believed that their copper teeth can speed up the time it takes for the poison to take effect, acting as a catalyst for a chemical reaction.
Moths belong to the genus Glycera, a group of polychaete worms and are found in shallow waters in marine environments. Their jaws are composed of 10 percent copper crystals and are so strong that one set can last a lifetime, which for a moth is up to five years. We can only assume that the metal rodents of Jaws, James Bond’s henchman, were inspired by these wriggling beasts.
Metal is rarely found in the animal kingdom, mainly because it is not easy to find in large quantities. Fortunately for the moth, its lifestyle of hiding in sediments means that it is able to absorb a lot of copper from its environment, but questions still remain as to how it then recycled these sediments into jaws.
A 2022 article solved the mystery by revealing a multitasking protein that contributes to the creation of metal worm teeth, performing an impressive set of six major functions. Even more impressive when you consider its simple composition, which mostly consists of glycine and a small amount of histidine.
The resulting dentition is a set of four intimidating fangs, made of copper, which are used for both biting prey and fighting off opponents. Yes, and, of course, to cripple the occasional field marine biologist.
Although reports of human moth bites are relatively rare, a 2022 case study in the journal Toxins describes the symptomatic poisoning experienced by a marine ecologist who was bitten while conducting field research. She described the sting as feeling very similar to a “bee sting” with pain, itching, and local anesthesia at the sting site for about a day, after which the stab wounds closed and erythematous patches formed in their place. On day 8, the patient sought medical attention from the facility’s expeditionary physician because the affected finger was swollen and had an unexpected discoloration, and the next morning was “very swollen, warm, but not painful” or sensitive but had pronounced vesicles at the puncture sites.
It wasn’t entirely clear whether the bite reaction was caused by venom, a secondary bacterial infection, or a combination of the two, but the authors say more bites need to be reported if we want to better understand how moth bites can affect human bites.
So, moths with metal teeth turn out to be not only amazing creatures of nature, but also potentially dangerous to humans. Their bite can cause pain, itching and anesthesia at the bite site, and in some cases can lead to swelling and discoloration of the skin. These unpleasant effects of a moth bite still need to be further studied.