Click Beetle
Agrypnus binodulus
A spring-loaded mechanism hidden on its underside
This click beetle has a long, narrow body and wing cases (elytra) marked with regular grooves. Flipped onto its back, it snaps a spine on its underside into a groove, releasing stored energy that flings it upright again. Its larva lives in the soil and is the familiar wireworm, a common underground pest.
Key figures
- Length
- About 14–18 mm; long, flat body with longitudinal grooves on the wing cases
- Life cycle
- Larval stage lasts 2–3 years; adults typically live only a few weeks
- Habitat
- Topsoil and leaf litter in farmland, grassland and forest edges
- Diet
- Larvae (wireworms) feed on plant roots, stems and seeds; adults mostly do not feed
- Clicking
- When overturned, a spine snaps into a groove on the midsection, releasing stored mechanical energy that flips it up with an audible click
- Self-righting
- The click serves double duty — righting the beetle and startling predators at the same time
Life cycle
Egg → Larva (wireworm, 2–3 years) → Pupa → Adult
Ecological role
Click beetle larvae (wireworms) live in the soil for extended periods, feeding on crop roots, stems and seeds, making them a common underground farmland pest; the nocturnal adults are, in turn, prey for birds and other predators.
Did you know
Flipped onto its back by a predator, the click beetle does not give up — the instant its spine snaps into the groove, it launches itself several centimeters into the air, righting itself and escaping.
Range
Most of China, the Korean Peninsula and Japan
Status
Common; the larva is one of the common underground pests of farmland
Anatomy
- Pronotum — The plate behind the head (pronotum) has two rear corners projecting into sharp points, forming the upper half of the click mechanism together with the spine
- Click Spine — A long spine projecting from beneath the front section that snaps into a groove on the midsection to release energy when clicking
- Elytra — Marked with neat longitudinal grooves, which give this click beetle its Chinese name
- Antenna — Saw-toothed, and can fold flat into grooves on either side of the head and thorax at rest
- Compound Eye — Positioned at the front sides of the head, detecting the approach of predators
- Legs — Relatively short; when threatened it relies on clicking away rather than running to escape
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