Beetles are insects that date back to around 300 million years. The order Coleoptera, the order in which they belong, is the largest order with more species that any other order in the animal kingdom. Even within the beetle class, there may be up to 1 million different species and may be more that have not yet been identified. There are so many different species of beetles that about 40% of all described insect species are classed as beetles.
Like all insects, the bodies of beetles are divided into three sections. Generally though, beetles can be characterized by their especially hard exoskeleton and their hard forewings called elytra. The elytra are actually not primarily used for flight, however, they are used to cover and protect the second pair of wings underneath it. This physical characteristic creates an armor for the beetle’s body and because the elytra must be lifted for flight, the beetle can maintain flexibility.
The legs of beetles can be modified for their environment. They vary depending on if they are running, swimming, digging, clawing, jumping, and all depends on the species of beetle. The legs are multi-segmented and although they are primarily used for walking, depending on the species and environment, they can be modified to be used differently. For instance, water beetles may have modified legs that help them float over the water. Other species, like ground beetles, have widened and spined legs that help them with digging. And furthermore, for another example, the legs of such species as flea beetles are enlarged legs which help them jump around.
Beetles use their antennae primarily as an organ for smell, however, beetles may use their antennae in other ways as well. They can be used to feel out the environment that the beetle is in at that time and some species even use their antennae during mating rituals. Other species even use their antennae as a means of defense.
Beetles, like most other insects, go through a complete life cycle of eggs, larvae, pupa, and adult.
A single adult female beetle may lay anywhere from 20 – several thousand eggs in one entire lifetime depending on the species of beetle. Also, they are usually laid according to their environment or the species of beetle. Some beetles lay their eggs in clumps, individually, or even buried into the food source. It will usually take 4 – 19 days before they hatch and enter the larval stage.
The larva are typically when the feeding stage will begin. They will start to eat a lot of food and keep growing. As the larva grows, they will continue to shed their exoskeleton. Some species will only go through one stage whereas other species can go through up to 30 different stages during the larval period. This means that for some species of beetles, the larval stage may be fairly short, but for some, it can be as long as several years before they go into the pupa stage. Just like the mature adult beetles, each species may have different physical qualities that are adapted their environment. These physical features may also aid as defense mechanisms such as the ability to camouflage to their environment.
The beetle will then enter the pupa stage, typically during the winter season. The pupa stage is most typically known as the cocoon stage. The pupa period may last up to 9 months before they emerge from their cocoons.
Adult beetles will emerge from the cocoon and will be ready to mate. Females will lay their eggs to begin a new generation of beetle. Adult beetles vary in size, color, and width but most species maintain a similar shape. Their lifespan also vary from just a few weeks to several years, depending on the species of beetle.
Beetles will feed on a wide variety of food sources due to their large number of different species. Their food source will also depend on availability in their habitats. Some species of beetles are omnivores, others are more specific with their diet, some species are carnivorous and will feed on other arthropods, and some will even feed on decaying organic matter or dead animals. Many species are actually just a nuisance pest and actually beneficial to the environment and agriculture. They are beneficial in that they are a natural control method for the population of other pests. They will eat pests that will feed on crops, others will feed on weed, and other species like dung beetles will feed on parasitic worms and flies. Although there are species of beetles that are beneficial to our environment, there are just as many species that can destroy crops and are considered agricultural and household pests. Some species will attack trees, crops like potato fields or wheat plants, and some will attack homes with a foundation of older wood.
Most other species are just considered a nuisance when they invade homes. In some parts of the world, natural predators will maintain the control of beetles, however, in some parts of the world, particularly in the United States, certain control measures must be made to maintain beetle infestations.
Damage in Homes
The most common beetles that people will come across in the United States may be the pests that invade homes and live, feed, and reproduce in homes. These may include the powderpost beetle, carpet beetle, or even the occasional pests, ladybugs. In some cases, these species of beetles may create significant damage to a home and invade in a serious manner. For instance, carpet beetles have a wide variety of food sources in the home and may feed on almost anything of animal origin like wool, furs, silk, and even leather. Therefore, significant damage will occur on expensive materials and can be extremely costly in the long run. Another example would be powderpost beetles. They attack hard wood which may include furniture or the actual flooring and walls. It is important to control these pests in the home before they become too costly.