Insect identification > Coleoptera > True Coleoptera > Snapping beetles

Snapping beetles

Family Elateridae (snapping beetles; click beetles; skipjacks). - These insects somewhat resemble the buprestids when adult but are usually more slender, with their sides more nearly parallel, and the economic species also lack a metallic reflection.

The hinder corners of the pronotum are elongated, forming sharp points in the majority of the group, and the insects are usually some shade of brown or black, though the pronotum and elytra sometimes differ in color and the latter are spotted in some cases, mottled black and white in our largest common species, and some have rather bright colors or markings.

When these insects fall on their backs, they are able to throw themselves into the air by a sudden snap of the body for the purpose of getting onto their feet as they alight again, and if this fails the first time the snapping is repeated.

The larvae, commonly called wireworms, are nearly all slender, yellow or brown, with very hard shells, often glistening, one subfamily where they are soft-bodied and white forming a notable exception to this. The outline of the hinder end is often made use of in distinguishing the different kinds of wireworms.

Their food habits have a wide range: some feed on decaying wood under bark or elsewhere; others on fungi; several groups are carnivorous; and still others feed on roots or seeds in the ground.

In the far South and also in the West Indies and Mexico are species of elaterids (Pyrophorus spp.) which have an oval, yellowish spot near each hinder corner of the pronotum, and also an area on the underside of the abdomen close to, and partially concealed by, the metathorax, which is luminous, producing an intermittent, greenish-yellow, quite brilliant light, making the insects very noticeable at night. They are beneficial, the larvae feeding on white grubs.

The injurious members of this family are those wireworms which feed on seeds and the roots of plants, and there are many kinds which have this habit. Some attack wheat; others corn; and still others feed on cotton, grass, potatoes, sugar beets and other crops, doing much damage.

So many species of wireworms are injurious and so unlike are their habits in different parts of the country that each kind seems to require treatment especially adapted to it.

Control. - Some general factors in control may, however, be suggested. When wireworms are abundant in low, poorly drained land, drainage will be of much assistance. When they attack grass roots in great numbers, it is desirable in cultivating such places to substitute field peas, buckwheat or some crop not closely related to grass for the first crop, if possible, even though this does violence to the general ideas of crop rotation. When sod land is to be planted, plowing it in July and cultivating often and deeply the rest of the summer will destroy many of the insects. In the South and in arid regions, however, the insects go deeply into the ground, during hot or dry weather, beyond reach by cultivation. In such cases planting early in the season and forcing the plants ahead by fertilizers and frequent cultivation are helpful. As the underground feeding period of these insects is from 3 to 6 years, proper treatment for a single season will at best give only partial relief, and to obtain the most successful control the special habits of the particular species concerned should be ascertained, and control measures to correspond be adopted. Various methods for the protection of planted seed have been tried but the results have not agreed in all cases and further studies along this line are needed.

The Elateridae is one of the most important groups of beetles from an economic standpoint, and injurious species occur practically everywhere in the United States. Several hundred kinds are known in this country.