Beetles are 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 described 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, with estimates suggesting that there are between 0.9 to 2.1 million total species. 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.
Elateridae or click beetles are a family of beetles. Other names include elaters, snapping beetles, spring beetles or skipjacks. This family was defined by William Elford Leach (1790–1836) in 1815. They are a cosmopolitan beetle family characterized by the unusual click mechanism they possess. There are a few other families of Elateroidea in which a few members have the same mechanism, but most elaterid subfamilies can click. A spine on the prosternum can be snapped into a corresponding notch on the mesosternum, producing a violent "click" that can bounce the beetle into the air. Clicking is mainly used to avoid predation, although it is also useful when the beetle is on its back and needs to right itself. There are about 9300 known species worldwide, and 965 valid species in North America.
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.
The beetle family Phengodidae is known also as glowworm beetles, whose larvae are known as glowworms. The females and larvae have bioluminescent organs. They occur throughout the New World from extreme southern Canada to Chile. The recently recognized members of the Phengodidae, the Cydistinae, are found in Western Asia. The family Rhagophthalmidae, an Old World group, used to be included in the Phengodidae.
Eucinetidae is a family of beetles, notable for their large coxal plates that cover much of the first ventrite of the abdomen, sometimes called plate-thigh beetles. The family is small for beetles, with about 50 species in 11 genera, but are found worldwide.
Cucujiformia is an infraorder of polyphagan beetles, representing most plant-eating beetles. It includes species from the major superfamilies of Chrysomeloidea, Curculionoidea, Cucujoidea, and Tenebrionoidea.
Staphyliniformia is a large infraorder of beetles. It contains over 70,000 described species from all regions of the world. Most species occur in moist habitats - various kinds of rotting plant debris, fungi, dung, carrion, many live in fresh water.
Scarabaeoidea is a superfamily of beetles, the only subgroup of the infraorder Scarabaeiformia. Around 35,000 species are placed in this superfamily and some 200 new species are described each year. Its constituent families are also undergoing revision presently, and the family list below is only preliminary.
The Elateroidea are a large superfamily of beetles. It contains the familiar click beetles, fireflies, and soldier beetles and their relatives.
The Lymexylidae, also known as ship-timber beetles, are a family of wood-boring beetles. Lymexylidae belong to the suborder Polyphaga and are the sole member of the superfamily Lymexyloidea.
Pselaphinae are a subfamily of beetles in the family Staphylinidae, the rove beetles. The group was originally regarded as a separate family named Pselaphidae. Newton and Thayer (1995) placed them in the Omaliine group of the family Staphylinidae based on shared morphological characters.
The Rhagophthalmidae are a family of beetles within the superfamily Elateroidea. Members of this beetle family have bioluminescent organs on the larvae, and sometimes adults, and are closely related to the Phengodidae, though historically they have been often treated as a subfamily of Lampyridae, or as related to that family. Some recent evidence suggested that they were the sister group to the Phengodidae, and somewhat distantly related to Lampyridae, whose sister taxon was Cantharidae, but more reliable genome-based phylogenetics placed as the sister group to the Lampyridae.
Hygrobia is a genus of aquatic beetles native to Europe, North Africa, China and Australia. It is the only genus in the family Hygrobiidae, also known as the Paelobiidae. These are known commonly as squeak beetles or screech-beetles.
The beetle genus Rhinorhipus contains a single species, Rhinorhipus tamborinensis from Queensland, Australia.
Eucnemidae, or false click beetles, are a family of polyphagan beetles including about 1700 species distributed worldwide.
Clambidae is a family of beetles. They are known commonly as the minute beetles or the fringe-winged beetles. They are found worldwide on every continent except Antarctica.
Omethidae is a family of Elateroidea sometimes known as the false soldier beetles.
Mysteriomorphus is an extinct genus of beetle, and the only member of the family Mysteriomorphidae. It is known from one described species, Mysteriomorphus pelevini found in Burmese amber, dating to the early part of the Cenomanian stage of the Late Cretaceous but more species are likely due to the morphological diversity of known specimens. It was initially placed in Elateriformia incertae sedis, but a subsequent study found that it was better placed within the Elateroidea, close to Elateridae.
Telegeusinae is a small subfamily of beetles in the family Omethidae recognizable by enlarged palpi found in males. Though relatively rare, males are sometimes found in large numbers in black light traps. Females are not known in this group, but it is theorized that females are larviform as found in many closely related taxa.
