Most recently reviewed by: Janet Hurley & Pat Porter (2018)
Common Name(s): Click beetle, Wireworm
Click beetles are elongated, parallel-sided and usually bear backward projections on the side corners of the shield behind the head (pronotum). They are somewhat flattened and range in size and color by species. Smaller species are about 1/4 inches long. Most species are brown to black in color, although some have reddish and yellowish colors and patterns. The eyed click beetle, Alaus oculatus (Linnaeus), reaches 1-½ inches in length and is beautifully marked with prominent oval eye spots on the pronotum and mottled gray wing covers. When placed on their backs, these beetles characteristically “click”, snapping their thoracic segments (prothorax and mesothorax) to cause their bodies to flip in the air to right themselves. Larvae, called “wireworms,” are usually hard-bodied, brownish, ½ to 2-½ inch long and cylindrical, with three pairs of tiny true legs behind the head and a flattened, and an ornamented shield-like segment on the tail end of the body.
The false click beetles (Eucnemidae) are similar to click beetles, and some species can even “click.” They are less common and usually occur in wood just beginning to decay. The Texas beetle, Brachypsectrida fulva LeConte (Coleoptera: Brachypsectridae) somewhat resembles a 3/16-inch long click beetle without the clicking mechanism. There is only one species in this family.
Habitat & Hosts
Larval stages (wireworms) damage seeds and seedlings of a wide variety of crops including alfalfa, beans, beets, clovers, corn, cotton, grasses, small grains (wheat, oats, etc.) many vegetable and bedding plants. They also tunnel into potato and sweet potato tubers. Larvae of some species, such as the eyed click beetle, occur in dead trees and rotting stumps and logs. Adults of Deilater have two light-producing spots on the thorax and one of the abdomen, somewhat similar to that of lightning bugs (Lampyridea).
In some years, adults are extremely numerous and enter homes and other structures in significant numbers. Adults do not damage plants.
Biology varies by species. In general, adults and larvae overwinter in the ground, becoming active in the spring. Adult females dig burrows and lay eggs around the base of host plants. Eggs hatch within a few weeks and larvae develop through several molts over a period of time from several months to over 4 years. They pupate in the cells within the soil in late summer or fall, and emerge as adults a few weeks thereafter. Generations can greatly overlap.
ManagementIf you live in the State of Texas, contact your local county agent or entomologist for management information. If you live outside of Texas, contact your local extension for management options.
Minimize wireworm infestations through clean cultivation and clean fallowing. Infestations are most severe in no-tillage or reduced-tillage situations, particularly following alfalfa, cover crops, or grain. Planting shallow and under warm conditions often allows cotton seeds to germinate quickly so plants can outgrow wireworm injury potential rapidly.
Larvae of some species damage seeds and underground parts of crop plants. Management in agricultural settings varies by crop, and growers should consult publications specific to the crop being grown. It is often the case that significant stand damage requires a replant of the crop.
Wireworm damage can be difficult to diagnose, in part because the larvae are highly mobile in the soil and may no longer be present. Look for chewed tissue on seeds and young plant parts below ground.
Time-lapse video showing wireworm larvae seeking shelter in soil. Video credit: Patrick Porter.
Insects in the City “Click beetles gone wild”
Wireworms at cottonbugs.tamu.edu