Stag Beetle

The oldest known fossil of the stag beetle dates back to the Middle Jurassic Period, approximately 150 to 160 million years ago.

The stag beetle is a family of large, hard-shelled, flying insects whose distinguishing trait is the ability to consume rotting wood as a larva. The name of this insect is derived from the giant mandibles on the male, which resemble the stags of a deer in the way they curve and branch. Their numbers appear to be declining in some parts of their range due to the loss of habitats and food sources.

3 Incredible Stag Beetle Facts!

• The giant mandibles for which this species is known have nothing to do with feeding. Instead, they allow the males to wrestle each other for access to females. The larger and stronger male usually emerges as the victor from the contest.
• After copulating with her partner, the female will often return to the place of her birth and lay around 30 eggs near rotting wood in the soil. The larvae emerge shortly later and spend a few years in grub form, feeding on the rotting wood. It undergoes a few different larval stages before becoming an adult. The total lifespan between larva and adult can sometimes reach up to seven years.
• The oldest known fossil of this insect dates back to the Middle Jurassic Period, approximately 150 to 160 million years ago. The form they were found in is known as a compression fossil, literally imprinted into sedimentary rock. Better-preserved fossils, dating back around 20 to 30 million years from the modern day Dominican Republic, were later found encased in amber.

Species, Types, and Scientific Name

The scientific name for the stag beetle family is Lucanidae. This name comes from the ancient Italian region of Lucania, at the southern end of the peninsula, where these beetles were used to make amulets. There are some 1,200 documented stag beetle species around the world. The best-known species is perhaps the European stag beetle, found all across the continent. Other well-known species include the multi-colored rainbow stag beetle of Australia and the cottonwood stag beetle of Arizona and the southwestern United States.

Appearance: How to Identify Stag Beetles

An adult is characterized by a wide segmented body and two pairs of wings. It is usually colored black or brown, but a select few species exhibit all manner of bright colors such as metallic green and iridescent red. The rainbow stag beetle has an entire range of bright rainbow colors. Adults normally grow 1 or 2 inches in length, but the largest species in the world, the giraffe stag beetle of southern Asia, measures about 5 inches long, much of which is just the massive mandibles. Males are obviously larger than females, again because of the mandibles. The larvae, by contrast, have a more grub-like appearance with an orange head. Measuring around 3 inches long, they’re generally larger than the adults, even without the giant mandibles.

While stag beetles have large mandibles, they generally do not bite humans. If they do do feel threatened and bite however, male stag beetle mandibles aren’t harmful while female bites can be quite painful.

Habitat: Where to Find Stag Beetles

This species is found all over the world, usually in places with loose soil and high average temperatures. While they tend to be found in wooded lands, they also occupy all kinds of unexpected places. The cottonwood stag beetle of Arizona is even known to consume the woodchips of playgrounds.

Diet: What Do Stag Beetles Eat?

The stag beetle is an herbivorous insect. Its digestive system is specifically adapted for consuming wood as food. The technical term for an animal that depends mostly on wood in its diet is a xylophage.

What eats the stag beetle?

This species is preyed upon by a wide range of different birds, amphibians, lizards, small mammals, and other insects. Crows, foxes, and kestrels are particularly common predators, especially when the beetle is most vulnerable in the mating season.

What does the stag beetle eat?

This insect spends the first several years of its life as a larva, feeding on rotten wood. The adult largely relies on the fat reserves left over from the larval stage to survive for the rest of its lifespan. When it does eat at all, the adult will consume rotting fruit or sap with its soft tongue.

Prevention: How to Get Rid of Stag Beetles

This species does not generally cause any harm to humans, because (unlike termites and other pests) they tend to live underground and feed on only rotting wood. Nevertheless, if you don’t want stag beetles lurking around your home, then the best way to get rid of them is to remove any remnants of rotting wood from your property. They are most likely to be found around rotting fences. Chemical use is generally not recommended, because it might cause more problems than it solves. Since population numbers have declined in many parts of their range (particularly Europe), it’s a good idea to just let them alone unless it’s absolutely necessary to remove them. Some people even deliberately encourage stag beetles by planting decaying wood on their property.