Stag Beetle – Pseudolucanus capreolus

Stag Beetle – Pseudolucanus capreolus
Family Lucanidae – Stag Beetles
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Live female adult stag beetle photographed at Winfield, Illinois, USA.
Relatively large beetles of the family Lucanidae are commonly known as stag beetles, after the males' elaborately branched and toothed mandibles, resembling the antlers of a stag. Stag beetles number only about 30 species in North America. They have chewing mouthparts and hardened outer wings, called elytra, which are used exclusively to cover the softer, membraneous flying wings underneath. The elytra meet in a straight line down the middle of the back. Their antennae are elbowed, with a club of leaf-like plates called lamellae, much as their cousins, the scarab beetles. However, the scarabs can furl thier lamellae (close the fan, so to speak) and the stags cannot.

Stag Beetle - Pseudolucanus capreolus
Mandibles are much reduced in this species

Stag beetles undergo complete metamorphosis, progressing through egg, larva, pupa, and adult stages. Female stag beetles generally lay their eggs under rotten bark on fallen logs. After hatching, the larvae bore into the dead wood and feed on the decay. A larva may take several years to get to the pupal stage, when they pupate underground. Adults emerge in springtime, and can live for 2 years. Not much is known about the feeding habits of adult stag beetles, but they are often seen flying to lights at night during the summer. When disturbed, a stag beetle will rear back and hold its head high with its mandibles open as a threat display. Stag beetles are undergoing a worldwide decline, as their hardwood forest habitat is slowly disappearing.

This female specimen is about 1 inch long. I found her  wandering across the bike path one evening.
I must confess to a bit of manipulation – I moved her into the foliage and posed her. What a magnificent insect !

Order Coleoptera: Beetles are the dominant form of life on earth: one of every five living species is a beetle. Coleoptera is the largest order in the animal kingdom, containing a third of all insect species. There are about 400,000 known species worldwide, ~30,000 of which live in North America.  Beetles live in nearly every habitat, and for every kind of food, there's probably a beetle species that eats it.
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