Click Beetle – Ampedus species
Live adult click beetles photographed at Winfield, Illinois. Size: 10mm
Beetles in the family Elateridae are commonly called click beetles, elaters, skipjack, snapping, or spring beetles. They possess a mechanism by which they can violently launch themselves several inches into the air, by which method they can avoid predators and right themselves if they happen to fall on their backs. A spine on the prosternum can be snapped into a corresponding notch on the mesosternum, producing a violent “click” which can bounce the beetle into the air. There are about 7000 known species.
Click beetles undergo complete metamorphosis: Egg – larvae (beetle larvae are called “grubs”) – pupa – adult. Some species of click beetle have larvae that have a hard shell, commonly called “wireworms.” These grubs can be serious agricultural pests, feeding as the do on the roots of plants (corn and other cereal grains are often attacked) during their 1-3 year portion of the life cycle. Wireworm larvae are hard, smooth, slender, wire-like worms varying from 2 to 1 inches in length when mature. They are a yellowish-white to a coppery color with three pairs of small, thin legs behind the head. The last body segment is forked or notched
Click beetles usually take three to four years to develop from the egg to an adult. Most of this time is spent as a larva. Generations overlap, so larvae of all ages may be in the soil at the same time. Wireworm larvae and adults overwinter at least 9 to 24 inches deep in the soil. When soil temperatures reach 50 to 55 degrees Fahrenheit during the spring, larvae and adults move nearer the soil surface. Adult females emerge from the soil, attract males to mate, then burrow back into the soil to lay eggs. Females can re-emerge and move to other sites where they burrow in and lay more eggs. This behavior results in spotty infestations throughout a field. Some wireworms prefer loose, light and well drained soils; others prefer low spots in fields where higher moisture and heavier clay soils are present.