Click beetles belong to the large family Elateridae, which includes thousands of species globally. They are characterized by an elongated, somewhat flattened body shape, often appearing in shades of dull brown or black. The common name comes from a unique mechanism that allows them to flip themselves over when they land on their backs, creating an audible “click” sound as they snap a specialized spine between their thoracic segments. This powerful movement can launch the beetle into the air, helping it to right itself or startle a potential predator.
The Total Lifespan of a Click Beetle
The complete life cycle of a click beetle typically spans between one and five years, with some species in colder climates documented to take up to six years. This duration encompasses four distinct phases: egg, larva, pupa, and adult. The largest percentage of this total time is spent hidden beneath the soil surface in the larval stage. The extended lifespan is a direct result of the slow development of the underground larval form.
The duration of the overall cycle is influenced by species-specific biology, coupled with environmental factors like food availability and soil temperature. A prolonged larval period ensures the insect reaches an adequate size and energy reserve before transforming into the short-lived adult. This means that a field infested with a particular species may contain individuals from multiple generations simultaneously.
The Wireworm Years: Larval Development
The larval stage of the click beetle is known as the wireworm, a name derived from its hard, slender, and segmented appearance. These juveniles are generally yellowish or reddish-brown, possessing a tough, shiny exoskeleton that allows them to tunnel through the soil with ease. Full-grown wireworms can range in size from about one-half inch to over an inch in length, depending on the species.
Wireworms are generalist feeders, consuming a variety of organic matter, which includes decaying vegetation, germinating seeds, and the roots of plants. Certain species are serious agricultural concerns because they bore into underground stems and tubers. Their slow growth rate and subterranean habitat mean they must constantly search for food.
The larval stage can last from two to six years, representing the vast majority of the beetle’s existence. Low temperatures and scarce food resources can extend this developmental period by several years as the wireworm waits for conditions to improve. Once the larva has stored sufficient energy, it constructs a small earthen cell underground to transition into the pupal stage.
Pupation is a relatively brief phase, typically lasting about a month, during which the insect transforms into its adult body plan. The newly formed adult beetle will often remain dormant in the soil cell over the winter, emerging only when the soil warms in the spring or summer to begin the final phase of its life.
The Adult Phase: Reproduction and Decline
The adult click beetle phase is primarily focused on reproduction and is the shortest period of the insect’s life, generally lasting only a few weeks to a couple of months. Once they emerge from the soil, their main biological imperative is to find a mate. A female may lay between 200 and 400 eggs in the soil, usually near plant roots, to start the cycle anew.
Many adult click beetles feed little, if at all, relying on the energy reserves accumulated during the multi-year wireworm stage. If they do feed, they typically consume nectar, pollen, or soft plant foliage, causing little to no damage to vegetation. The adults are often nocturnal, attracted to lights at night.
Once mating and egg-laying are complete, the adult beetle’s short life quickly comes to an end. This final, winged form is a vehicle for dispersal and reproduction.