Colorado potato beetle in the context of "Beetles"

Beetles are insects that form the order Coleoptera (/koʊliːˈɒptɛrə/), in the superorder Holometabola. 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 arthropods and 25% of all known animal species; new species are discovered frequently, with estimates suggesting that there are between 0.9 and 2.1 million total species. Other similarly diverse orders are dipterans (flies) and hymenopterans (wasps).

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 (ladybirds or ladybugs) eat aphids, scale insects, thrips, and other plant-sucking insects that damage crops. Some others also have unusual characteristics, such as fireflies, which use a light-emitting organ for mating and communication purposes.

The beetle family Chrysomelidae, commonly known as leaf beetles, includes over 37,000 (and probably at least 50,000) species in more than 2,500 genera, making it one of the largest and most commonly encountered of all beetle families. Numerous subfamilies are recognized, but the specifics of leaf beetle taxonomy and systematics are likely to change with ongoing research.

Adult and larval leaf beetles feed on a variety of plant tissue, with some being specialists of particular species or families of plant. Many are serious pests of cultivated plants, for example the Colorado potato beetle (Leptinotarsa decemlineata), the asparagus beetle (Crioceris asparagi), the cereal leaf beetle (Oulema melanopus), the mustard beetle (Phaedon cochleariae) and various flea beetles, and a few act as vectors of plant diseases. Others are beneficial due to their use in biocontrol of invasive weeds. Some Chrysomelidae are conspicuously colored, typically in glossy yellow to red or metallic blue-green hues, and some (especially Cassidinae) have spectacularly bizarre shapes. Thus, they are highly popular among insect collectors.