Ironclad Beetle: It's Tough

The ironclad beetles are a small subfamily of beetles found mostly in North and Central America, with a few species found in South America. Very little is known about most species in the subfamily. They are often difficult to find and even harder to study. However, we do know a few things.

In some cultures, these beetles are sold as living jewelry. Vendors glue imitation jewelry to the exoskeleton of the beetle, attach a small gold chain to it, then sell it to tourists. The chain is used to hold the beetle to the person while still allowing it to walk around.1 They cannot fly and move relatively slowly anyway, so the beetles don’t seem to be too bothered by the arrangement.

Most of these species live on trees and munch on the fungi that grow there. They are mostly solitary and tend to live in hot, dry regions. They can survive for months without food or water. When threatened, the beetles simply play dead and rely on their incredible toughness to ward off the predator. They can live up to eight years and, because they are so tough, they have few predators.

"Ironclad Beetle" by Katja Schulz licensed under CC BY 2.0 via Wikimedia Commons

Ironclad beetles are notoriously tough. When placing them in collections, beetle collectors often have to drill a small hole in the exoskeleton in order to stick a pin into it. These beetles are so tough that you can run over them with a car, and they will walk away unbothered.2 You can’t possibly kill them by stepping on them. It turns out that the beetle’s exoskeleton is not rigid but flexible. There is a special joint held together like a jigsaw puzzle on the beetle’s back. These pieces break under pressure, then immediately reseal when the pressure goes away. Other parts that protect the vital organs are so tough that they do not bend under significant pressure. These beetles can handle the pressure of up to 39,000 times their own body weight.