Beetles are the group of insects with the largest number of known species. They are classified in the order Coleoptera (pronounced /ˌkəʊliˈɒptərə/; from Greek κολεός, koleos, "sheath"; and πτερόν, pteron, "wing", thus "sheathed wing"), which contains more described species than in any other order in the animal kingdom, constituting about 25% of all known life-forms. 40% of all described insect species are beetles (about 350,000 species), and new species are frequently discovered. Estimates put the total number of species, described and undescribed, at between 5 and 8 million. The largest family also belongs to this order—the weevils, or snout beetles, Curculionidae.
Beetles can be found in almost all habitats, but are not known to occur in the sea or in the polar regions. They interact with their ecosystems in several ways. They often feed on plants and fungi, break down animal and plant debris, and eat other invertebrates. Some species are prey of various animals including birds and mammals. Certain species are agricultural pests, such as the Colorado potato beetle Leptinotarsa decemlineata, the boll weevil Anthonomus grandis, the red flour beetle Tribolium castaneum, and the mungbean or cowpea beetle Callosobruchus maculatus, while other species of beetles are important controls of agricultural pests. For example, beetles in the family Coccinellidae ("ladybirds" or "ladybugs") consume aphids, scale insects, thrips, and other plant-sucking insects that damage crops.
Flour beetles are members of the darkling beetle genera Tribolium or Tenebrio. They are pests of cereal silos and are widely used as laboratory animals, as they are easy to keep. The flour beetles enjoy wheat and other grains and are adapted to survive in very dry environments. They are a major pest in the agricultural industry and are highly resistant to insecticides.
The larvae of T. molitor when full-grown are known as mealworms, small specimens and the larvae of the other species are called mini mealworms.
Confused flour beetle
The confused flour beetle (Tribolium confusum), a type of darkling beetle known as a flour beetle, is a common pest insect known for attacking and infesting stored flour and grain. They are one of the most common and most destructive insect pests for grain and other food products stored in silos, warehouses, grocery stores, and the home.
The confused flour beetle is very similar in appearance and habit to the Red Flour Beetle , Tribolium castaneum and the Destructive Flour Beetle, Tribolium destructor. In fact, this similarity and the resulting confusion over the identity of the beetle is the origin of its name. Both the confused flour beetle and red flour beetle are small, about 1/8 to 1/4 inch in length, and reddish-brown in color. The primary distinguishing physical difference is the shape of their antennae: the confused flour beetle's antennae increase gradually in size and have four clubs, while the red flour beetle's antennae have only three. Additionally, red flour beetles have been known to fly short distances, while confused flour beetles do not. Tribolium destructor is much darker than either and less common.
While confused (and red) flour beetles cannot feed on whole, undamaged grain, they are often found in large numbers in infested grains, feeding off of broken grain, grain dust, and other household food items like flour, rice, dried fruit, nuts, and beans. Both types of beetles are often found not only in infested grains, but in crevices in pantries and cabinets as well. Damage to food is caused somewhat by the beetles' feeding, but also by their dead bodies, fecal pellets, and foul-smelling secretions. In addition to creating a foul odor, the beetles' presence encourages the growth of mold.
True Powderpost beetles are a group of woodboring beetles in the insect subfamily Lyctidae and the false powderpost beetles, the family Bostrichidae. These, and other woodboring beetles Anobiidae (anobiid, Anobium punctatum (common furniture beetles), and deathwatch beetles), all fall in the superfamily Bostrichoidea. The damage caused by the family Cerambicidae (the most common is the Old House Borer) is often confused with that of powder post beetles. However the damage is often very old, and of no consequence.
The term "powderpost" comes from the fact that the larvae of these beetles feed on wood and, given enough time, can reduce it to a mass of fine powder. They are therefore considered pests. The family Anobiidae is the only one capable of digesting cellulose, the primary ingredient of wood, and all other species excrete the wood without digesting it.
Powderpost beetles spend months or years inside the wood in the larval stage. Their presence is only apparent when they emerge from the wood as adults, leaving pin hole openings, often called "shot holes" behind and piles of powdery frass below. Shot holes normally range in diameter from 1/32 inch (0.8 mm), to 1/8 inch (3 mm), depending on the species of beetle. If wood conditions are right, female beetles may lay their eggs and reinfest the wood, continuing the cycle for generations. Heavily-infested wood becomes riddled with holes and rooms or basements packed with a dusty frass — wood that has passed through the digestive tract of the beetles. The larvae feed mainly upon starch in the wood.
Depending on the species, Powderpost beetles can feed upon certain hardwoods or softwoods. Some hardwoods are naturally immune, if they have low starch content, or if the pore (vessel) diameters are too small for the female beetle's ovipositor which prevents her from inserting eggs into the substrate.
Wood preservatives can be used to treat the wood and prevent beetle infestation. The most common treatment uses boron.
Items that can be infested by powderpost beetles include any wooden tools or tool handles, frames, furniture, gun stocks, books, toys, bamboo, flooring, and structural timbers.
The brown, hairy larvae or cast skins of carpet beetles usually are found in stored woolens, carpeting, lint accumulations, cracks and corners of closets, dresser drawers, and occasionally, in stored food and cupboards. The larvae are quite active and may appear almost anywhere in the house. It is probable that every home has some carpet beetles, although finding just a few is not usually considered a problem.
Adult carpet beetles are small, oval, black, and approximately 1/8-inch long. The adult beetles feed on pollen. The larvae often feed on lint but can cause serious damage by feeding on animal fibers—wool, fur, feathers, hair, bristles, mohair—in clothing, carpeting, upholstery, and other household furnishings. They do not feed on synthetic fabrics. Carpet beetles can also be pests in dried food products, such as flour, corn meal, cereal, and other similar foods.
Housekeeping is important. Regular, thorough removal of lint eliminates insect breeding places. Pay particular attention to rugs, carpets (especially next to walls), upholstered furniture, closets, shelves, radiators (and the space under and behind them), registers and ducts, baseboards, moldings, corners, and floor cracks.
Inspect clothing and storage areas in the fall and spring for potential infestations. Also periodically check that windows and airducts are properly screened to help prevent the entry of insects.
Dry clean or launder clothing before storing as carpet beetles are more apt to infest soiled material. Store clothing in tight boxes or chests. It is generally not advisable to use plastic bags. Although they may not harm clothing during short-term storage (several months) long-term storage could result in damage to clothing due to moisture problems or potential reactions between the plastic and the fabric.
Place mothballs or crystals (naphthalene) or part of a no-pest strip (dichlorvos) with the clothes in storage container. The smell of naphthalene may be difficult to remove from clothing. Dry clean clothing again before wearing to help remove any odor. No-pest strips may be difficult to find in stores. Cedar chips, although popular as an insect repellent, do not effectively deter carpet beetles.
Get rid of or properly store remnants or scraps of wool, fur, fleece, and other material.
Woolen garments and less expensive furs can be stored in a closet used for that purpose only. A no-pest strip hung in a closed closet will protect the garments for 3 to 4 months. One no-pest strip protects 1,000 square feet. Cut it into smaller pieces if the storage area is smaller. Do not use scissors or knives used to cut no-pest strips on food or food packaging.
If you find the larvae or their shed skins, inspect your home thoroughly. If insect numbers are low, you generally can handle the control yourself. However, local pest control operators have the experience, training, and equipment to do an effective job when excessive numbers of insects over a large area are present.
If you tackle the job yourself, start with a thorough search—
•of stored woolens in chests, boxes, and closets; •of remnants of flannel, wool, fleece, or felt in closets, attics, and basements; •under covers of upholstered furniture; •in lint that accumulates in floor cracks, registers, or cold air ducts; •under rugs, carpets, and pads—especially around edges or under seldom-moved furniture; •under baseboards, moldings, and trim.
If the infestation is localized, remove infested material possible. Carpet beetle larvae and eggs can be killed by placing infested items in freezing temperatures for 48 hours. Clothing can also be dry cleaned or ironed. Then apply a suitable insecticide to the storage area surfaces.
If the trouble is spread throughout the building, clean thoroughly and apply an appropriate insecticide. Various insecticides are available to the public as ready to use aerosol sprays, including 0.5% chlorpyrifos, 0.2–0.5% permethrin, 1.0% propoxur, 0.1–0.25% allethrin by many manufacturers, including Black Flag, Ortho, and Raid. Read all insecticide label directions carefully!
Those wishing to use a professional service can contact a pest control operator as they have a wider range of products to choose from.
Apply the spray to baseboards, closet corners, and carpet edges. If the infestation is heavy, loosen and turn back the carpet edges and spray both sides. Since some chemicals can stain certain carpets, always test chemicals on a small inconspicuous part of the carpet before extensive spraying.
If upholstered furniture is infested, have it fumigated by a professional or, in winter, put the furniture outside in temperatures of zero or below for at least 48 hours.