Eyed Click Beetle

Alaus oculatus and the broader family Elateridae (click beetles) are famous for an extraordinary self-righting mechanism. When a click beetle ends up on her back — typically after falling from a tree or being threatened — she would die without a way to right herself. Click beetles solve this with a spring-loaded thoracic 'click': a peg on the prosternum is locked against a notch on the mesosternum under tension, and when released, the prothorax snaps back with such force that the beetle's body launches into the air. The release is fast (about 0.5 milliseconds), accelerates the beetle at 380 g (40× the lethal limit for humans), and propels her 25-30 cm into the air. She often lands right-side-up. The audible 'click' is the snap of the spring mechanism, not a deliberate sound. Click beetle larvae (called 'wireworms') are major agricultural pests of root crops — they live underground for 2-5 years feeding on plant roots. The eyed click beetle (Alaus oculatus) is one of the largest North American species, with two prominent eyespot markings on the pronotum that startle predators.