Extension Entomology

Click Beetle / Wireworm

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Most recently reviewed by: Janet Hurley & Pat Porter (2018)

Common Name(s): Click beetle, Wireworm

Description

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.

Life Cycle

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.

Management

If 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.

Wireworm damage to cotton seedlings. Photo credit: Patrick Porter.

Wireworm damage to cotton seedlings. Photo credit: Patrick Porter.

 

Time-lapse video showing wireworm larvae seeking shelter in soil. Video credit: Patrick Porter.

Related Publications

Insects in the City “Click beetles gone wild”

Wireworms at cottonbugs.tamu.edu

Bugwood Images

Velvet Ants

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Bastiaan M. Drees, Professor and Extension Entomologist

Velvet ants commonly are encountered in arid, sandy areas of Texas. Although related to wasps, the wingless females resemble ants and have a dense coating of velvety hair. Males have wings and actively fly. They are in the family Mutillidae in the order Hymenoptera that also contains ants, wasps, bees and sawflies.
Krombein et al. (1979) list 30 genera of Mutillidae in found in North America. Of these at least 84 species are possibly considered to be “velvet ants” and occur in Texas. These species are from the three genera: Timulla – 15 species, Ephuta – 9 species, and Dasymutilla – 60 species. Many other species are listed for this family of insects, but most are not normally thought of as the day-active (diurnal), fuzzy or hair-covered, and colorful “velvet ant” species. The most commonly encountered and largest species is known as the cow killer, Dasymutilla occidentalis comanche Blake (Fig. 1).

Figure 1 (left). The cow killer, Dasymutilla occidentalis, adult female.

Figure 1. The cow killer, Dasymutilla occidentalis, adult female.

Figure 2. Another species of “velvet ant” (Hymenoptera: Mutillidae)

Figure 2. Another species of “velvet ant” (Hymenoptera: Mutillidae)

Biology

      Velvet ants are solitary wasps. Immature stages or larvae feed externally on the prepupal or pupal stages of ground-nesting bees, other wasps and some flies and beetles. The wingless females actively search for hosts on which to deposit eggs. The host is attacked after its cocoon has been spun, or the puparium formed. Upon locating a suitable host, the female penetrates the cocoon or puparium with its long ovipositor (which can also function as the stinger) and deposits one or two eggs.
Eggs hatch and young larvae feed on the host, devouring it. After feeding, the velvet ant larva spins its own cocoon within that of its host. Over-wintering occurs as the prepupal stage inside the host’s cocoon. Developmental times vary between species and in response to various environmental conditions.
Upon emerging as adults, winged males fly in search of mates. The wingless females attract males of their own species using specific sound produced by a rasping structure located between their second and third abdominal segments. Mating lasts for only a few seconds. Males not searching for females are often found visiting flowers in search of nectar. They do not live as long as the wingless females.

Importance

      Females spend much time in sandy areas searching for hosts and may be encountered at close range by adults and children. The females are capable of stinging repeatedly. The stinger is long, and the sting is reportedly quite painful–perhaps the reason that the large common species is called the “cow killer”.
People are most often stung by velvet ants on the foot while walking in infested areas without proper footwear. The intensity of pain and reaction to the sting will vary according to the sensitivity of the person stung.
Luckily, these are solitary creatures and the possibility of being stung by a number of these insects at one time is unlikely.
No one has documented the importance of velvet ants as parasites of other insects. Ground dwelling bees, often important in the pollination of some crops such as alfalfa, are known to be hosts for velvet ants. Other species are reportedly pests of white grub parasites, a condition known as hyperparasitism. In each of these different examples, velvet ants can be considered either beneficial or pestiferous depending upon the host species.

Control Measures

      Chemical control of velvet ants is rarely justified. The best methods for coping with velvet ants are: 1) the education of youngsters not to (or carefully) handle these insects and 2) wearing shoes in infested areas to avoid accidental encounters. These insects are very hard-bodies and difficult to crush by stepping on them. Also, their long stingers (modified egg-laying structure or ovipositor) are flexible and can inflict a painful sting even when the end of the abdomen is not directly contacting skin.
Occasionally, numbers of velvet ants occur in certain areas such as gardens or underneath houses, trailers or other structures raised from the ground. In these cases, the best control tactic is to eliminate ground-nesting wasps or bees on which immature velvet ants feed. Contact insecticides with label directions for “digger wasps” can be used to attempt to control such insects. For information on controlling the hosts, see L-1828 “Paper wasps, Yellowjackets and Solitary Wasps” (http://tcebookstore.org/tmppdfs/22109649-L1828.pdf. Individual velvet ants can be killed by crushing or by using directed sprays of household aerosol formulations with “crawling insects” or “wasp nests” that often contain synergized pyrethrins or synthetic pyrethroids such as resmethrin are available for wasp control.

Literature cited

Krombein, K. V., P. D. Hurd, Jr., D. R. Smith, and B. D. Burks. 1979. A Catalog of Hymenoptera in North America North of Mexico, Volume 2. Smithsonian Institution Press, Washington, D. C. (Family Mutillidae, pages 1276-13142209 pages.

Acknowledgments

The author wishes to thank Dr. Jerry Cook, entomologist with Sam Houston State University, and Ed Riley, Assistant Curator for the Texas A&M University Department of Entomology for their review and helpful comments in the development of this fact sheet.

All pesticides are potentially hazardous to human health and the environment. As a pesticide user, you are legally required to read and carefully follow all directions and all safety precautions on the container label. Label instructions are subject to change, so read the label carefully before buying, using and disposing of any pesticide. Regardless of the information provided in an Extension publication, always follow your product’s label. When in doubt about any instructions, contact your pesticide seller, or the manufacturer listed on the label, for clarification. All pesticides should be stored in their original labeled containers and kept out of the reach of children. Never pour leftover pesticides down a storm drain or any other drain.

Red Harvester Ants

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Bastiaan M. Drees*
*Professor and Extension Entomologist, The Texas A&M University System.

Red harvester ants are one of the more noticeable and larger ants in open areas in Texas. Eleven species in this group of ants (genus Pogonomyrmex) are known from the state. However, harvester ants are not nearly as common today as they were during the earlier 1900s. The decline, particularly in the eastern part of the state, has caused some alarm because these ants serve as a major source of food for the rapidly disappearing and threatened Texas horned lizard.

Description
Red harvester ants on ground

Red harvester ants

Worker ants are 1⁄4 to 1⁄2 inch long and red to dark brown. They have squarish heads and no spines on the body. There are 22 species of harvester ants in the United States, 10 of which are found in Texas. Seven of these species are found only in far west Texas.

Life cycle

Winged males and females swarm, couple and mate, especially following rains. Winged forms are larger than worker ants. Males soon die and females seek a suitable nesting site. After dropping her wings, the queen ant digs a burrow and produces a few eggs. Larvae hatch from eggs and develop through several stages (instars). Larvae are white and legless, shaped like a crookneck squash with a small distinct head. Pupation occurs within a cocoon. Worker ants produced by the queen ant begin caring for other developing ants, enlarge the nest and forage for food.

Pest status

Worker ants can give a painful, stinging bite, but are generally reluctant to attack. Effects of the bite can spread along lymph channels and can be medically serious. Harvester ant workers commonly are sold for ant farms.

Nest of red harvester ants in ground

Nest of red harvester ants

Habitat

Worker ants remove vegetation in circular areas or craters around nests. Colonies occur in open areas and usually have a single central opening. The area around the opening usually has small pebbles deposited on the soil surface by the worker ants. Often there is no vegetation within a 3- to 6-foot circle around the central opening of the colony, and along foraging trails radiating from the colony. Colonies usually are widely separated; however, heavy infestations in pasture and rangeland can reduce yield. Red harvester ants also colonize in ornamental turf areas where their presence may be undesirable. They do not invade homes or structures.

Food sources

Red harvester ant foragers collect seeds and dead insects and store them in the nests as food for the colony. The ants’ mouthparts are designed for chewing.

Management

Red harvester ants are native species and are generally not considered to be serious pests. Consider the option of not controlling these ants, especially in areas inhabited by the few remaining horned lizards (see box).

Help Save the Texas Horned Lizard
The Texas horned lizard is a protected threatened species. It is commonly called “horny toad.”

Full-grown lizards are normally 2 1⁄2 to 4 1⁄4 inches from the snout to the tip of the tail, although some grow larger. They have broad, flattened bodies and bear a crown of spines at the back of the head. Their color varies by the background color of the habitat in which they live.

Populations of the horned lizard and the harvester ant, on which it predominantly feeds, have declined in the eastern part of Texas. There are several possible factors contributing to the decline of these species.

■ Red imported fire ants are believed to eliminate harvester ants and prevent new colonies from forming by preying on mated queen harvester ants.

■ Red imported fire ants may prey directly on lizards or on hatching eggs of lizards.

 ■ Many insecticides used to control or eliminate the red imported fire ant are toxic to the harvester ant, and eliminate the harvester ant more efficiently than they eliminate fire ants. Broadcast applications of fire ant bait products should be avoided in areas where harvester ants are found.

■ Horned lizards normally inhabit flat, open, dry country with little cover. Urbanization, mowing, shredding, shallow discing and other land use practices can eliminate or reduce the production of weed seeds on which harvester ants feed. Harvester ants and horned lizards, which are dependent upon this ant species, cannot survive in these disturbed habitats.

Horned Lizard illustration in color

However, in certain cases, elimination of red harvester ants may be necessary. Destruction of their nests and habitat through regular discing and mowing may eliminate them without resorting to use of insecticides. If pesticides are selected, use registered products selectively and carefully follow instructions provided on the label.

Although any insecticide registered to control “ants” can be used to control harvester ants, few are registered specifically to control these species (Table 1). Harvester ants can be quickly eliminated using Amdro® Pro Fire Ant Bait (0.73 percent hydramethylnon) or similar products. Individual colonies can be treated using 2 to 5 tablespoons of product scattered around the colony’s central opening. In larger areas, the product can be broadcast at a rate of 1 to 1 1⁄2 pounds product per acre (2 to 3 ounces per 5,000 square feet) using a suitable application device such as a hand-cranked seeder or the electric-driven mountable Herd GT Model 77 Seeder. Amdro® can be used in lawns, landscaped areas, golf courses, other noncropped areas, grounds surrounding poultry houses, corrals, other animal holding areas, nonbearing ornamental nursery stock, pasture and rangeland. Do not cut and bale hay from treated cattle pastures and rangeland until 7 days after bait application.

Table 1. Insecticide products available for treatment of harvester ants.

Common name and formulation Product name*
abamectin B1 0.011% Advance 375A Select Granular Ant Bait Advance Granular Ant Bait Formula 1 Advance Granular Carpenter Ant Bait
acephate 50% Ortho Orthene Fire Ant Killer
bifenthrin 0.115% Ortho Bug B Gone Max Insect Killer for Lawns Basic Solutions by Ortho, Lawn & Garden Insect Killer
boric acid 7.5% AntX 75
hydramethylnon 0.365% plus s-methoprene 0.250% Extinguish Plus
hydramethylnon 0.73% Amdro Pro Fire Ant Bait
hydramethylnon 1.0% Maxforce Fire Ant Killer Granular Bait Maxforce Professional Insect Control Fine Granule Insect Bait Maxforce Professional Insect Control Granular Insect Bait
*Other products with different trade names may be available.

Suggested pesticides must be registered and labeled for use by the Environmental Protection Agency and the Texas Department of Agriculture. The status of pesticide label clearances is subject to change and may have changed since this publication was printed. County Extension agents and appropriate specialists are advised of changes as they occur.

The USER is always responsible for the effects of pesticide residues on his livestock and crops, as well as for problems that could arise from drift or movement of the pesticides from his property to that of others. Always read and follow carefully the instructions on the product label.

In noncrop areas, a contact insecticide such as products containing bifenthrin or acephate can be applied as directed to individual ant nests. When using Ortho Orthene® Fire Ant Killer (acephate 50 percent) apply as a dry application as directed. Other products may require water to wash the insecticide off of the dust or granular formulation and into the ant nest.

Additional Information

Drees, B.M. and J.A. Jackman. A Field Guide to Common Texas Insects. Gulf Publishers, 1998.

Garrett, J.M. and D.G. Barker. Texas Monthly Field Guide Series – A Field Guide to Reptiles and Amphibians of Texas. Gulf Publishing Co., 1987.

Web site: http://ento.www.tamu.edu/extension/ index.html.

Acknowledgment

The author appreciates review comments from Dr. John Jackman, Dr. Dawn Gouge and Dr. Pat Morrison.

The information given herein is for educational purposes only. Reference to trade names is made with the understanding that no discrimination is intended and no endorsement by the Texas Agricultural Extension Service is implied.