Beetles are a group of insects that form the order Coleoptera, in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 species, is the largest of all orders, constituting almost 40% of described insects and 25% of all known animal life-forms; new species are discovered frequently. The largest of all families, the Curculionidae (weevils) with some 83,000 member species, belongs to this order. Found in almost every habitat except the sea and the polar regions, they interact with their ecosystems in several ways: beetles often feed on plants and fungi, break down animal and plant debris, and eat other invertebrates. Some species are serious agricultural pests, such as the Colorado potato beetle, while others such as Coccinellidae eat aphids, scale insects, thrips, and other plant-sucking insects that damage crops.
Stag beetles are a group of about 1,200 species of beetles in the family Lucanidae, presently classified in four subfamilies. Some species grow to over 12 cm (4.7 in), but most are about 5 cm (2.0 in).
Ground beetles are a large, cosmopolitan family of beetles, Carabidae, with more than 40,000 species worldwide, around 2,000 of which are found in North America and 2,700 in Europe. It is one of the ten most speciose animal families, as of 2015.
The insects of the beetle family Chrysomelidae are commonly known as leaf beetles, and include over 37,000 species in more than 2,500 genera, making up one of the largest and most commonly encountered of all beetle families. Numerous subfamilies are recognized, but only some of them are listed below. The precise taxonomy and systematics are likely to change with ongoing research.
The Hydroscaphidae are a small family of water beetles known commonly as skiff beetles. As of 2010, there are 23 species in the family. Several are recently described.
The rove beetles are a family (Staphylinidae) of beetles, primarily distinguished by their short elytra that typically leave more than half of their abdominal segments exposed. With roughly 63,000 species in thousands of genera, the group is currently recognized as the largest extant family of organisms. It is an ancient group, with fossilized rove beetles known from the Triassic, 200 million years ago, and possibly even earlier if the genus Leehermania proves to be a member of this family. They are an ecologically and morphologically diverse group of beetles, and commonly encountered in terrestrial ecosystems.
The longhorn beetles are a cosmopolitan family of beetles, typically characterized by extremely long antennae, which are often as long as or longer than the beetle's body. In various members of the family, however, the antennae are quite short and such species can be difficult to distinguish from related beetle families such as the Chrysomelidae. The family is large, with over 26,000 species described, slightly more than half from the Eastern Hemisphere. Several are serious pests. The larvae, called roundheaded borers, bore into wood, where they can cause extensive damage to either living trees or untreated lumber. A number of species mimic ants, bees, and wasps, though a majority of species are cryptically colored. The rare titan beetle from northeastern South America is often considered the largest insect, with a maximum known body length of just over 16.7 cm (6.6 in). The scientific name of this beetle family goes back to a figure from Greek mythology: after an argument with nymphs, the shepherd Cerambus was transformed into a large beetle with horns.
Woodworm is the wood-eating larvae of many species of beetle. It is also a generic description given to the infestation of a wooden item by these larvae.
Polyphaga is the largest and most diverse suborder of beetles. It comprises 144 families in 16 superfamilies, and displays an enormous variety of specialization and adaptation, with over 350,000 described species, or approximately 90% of the beetle species so far discovered.
Darkling beetle is the common name of the large family of beetles, Tenebrionidae. The number of species in the Tenebrionidae is estimated at more than 20,000 and the family is cosmopolitan in distribution.
The Adephaga, with more than 40,000 recorded species in 10 families, are a suborder of highly specialized beetles and the second-largest suborder of the order Coleoptera. Members of this suborder are adephagans, a term which notably include ground beetles, tiger beetles, predacious diving beetles, and whirligig beetles. The majority of the species belongs to the family of carabids, or ground beetles (Carabidae).
Buprestidae is a family of beetles known as jewel beetles or metallic wood-boring beetles because of their glossy iridescent colors. Larvae of this family are known as flatheaded borers. The family is among the largest of the beetles, with some 15,500 species known in 775 genera. In addition, almost 100 fossil species have been described.
Hydrophilidae, also called water scavenger beetles, is a family of chiefly aquatic beetles. Aquatic hydrophilids are notable for their long maxillary palps, which are longer than their antennae. Several of the former subfamilies of Hydrophilidae have recently been removed and elevated to family rank; Epimetopidae, Georissidae, Helophoridae, Hydrochidae, and Spercheidae. Some of these formerly-included groups are primarily terrestrial or semi-aquatic.
Dermestidae are a family of Coleoptera that are commonly referred to as skin beetles. Other common names include larder beetle, hide or leather beetles, carpet beetles, and khapra beetles. There are approximately 500 to 700 species worldwide. They can range in size from 1 to 12 mm. Key characteristics for adults are round oval shaped bodies covered in scales or setae. The (usually) clubbed antennae fit into deep grooves. The hind femora also fit into recesses of the coxa. Larvae are scarabaeiform and also have setae.
Cleridae are a family of beetles of the superfamily Cleroidea. They are commonly known as checkered beetles. The family Cleridae has a worldwide distribution, and a variety of habitats and feeding preferences.
Leiodidae is a family of beetles with around 3800 described species found worldwide. Members of this family are commonly called round fungus beetles due to the globular shape of many species, although some are more elongated in shape. They are generally small or very small beetles and many species have clubbed antennae.
Ptinidae is a family of beetles in the superfamily Bostrichoidea. There are at least 220 genera and 2,200 described species in Ptinidae worldwide. The family includes spider beetles and deathwatch beetles.
Agyrtidae, or primitive carrion beetles, are a small family of polyphagan beetles They are found in mostly temperate areas of the northern hemisphere and in New Zealand. They feed on decaying organic material.
Coccinellidae is a widespread family of small beetles ranging in size from 0.8 to 18 mm. The family is commonly known as ladybugs in North America, and ladybirds in Britain and other parts of the English-speaking world. Entomologists widely prefer the names ladybird beetles or lady beetles as these insects are not classified as true bugs.
Biphyllidae or False Skin Beetles is a family of beetles, in the suborder Polyphaga. Worldwide, about 195 species are known. They live under the bark of dead trees and feed on fungi. It contains the following genera:
