Beetles are a general term for arthropods in the order Coleoptera of the subphylum Tracheal, and are the largest group (order) in the insect class. There is a significant difference in size between different species, and the body wall is hard; Chewing mouthparts, with the upper palate generally well-developed; The forewings are keratinized, hard, and lack wing veins, known as elytra. When at rest, they cover the back, the middle and posterior thorax, and most or all of the abdominal segments (the small scutum of the middle thorax is usually exposed). The inner edges of the two elytra meet at the midline of the back to form a straight line; The posterior wing membrane is generally large and folded vertically and horizontally under the elytra, with different folding patterns in different groups; Feet have various morphological variations, suitable for brisk walking, swimming, jumping, digging, or grabbing. Some beetles have a lifespan of over 25 years, with the highest record reaching 30 years.

Beetles are widely distributed on land, in the air, and in various water bodies except for the ocean and snow. Food includes a variety of fresh, decaying animals and plants. The number of eggs laid varies depending on the species, with some producing only 1 or 2 eggs and others up to 1000 eggs. Completely metamorphosed insects undergo four developmental stages throughout their life cycle: egg, larva, pupae, and adult.

Among predatory beetles, there are many that are beneficial to humans, such as floaters, step beetles, and tiger beetles. The Australian ladybug in the family Nymphalidae is a natural enemy insect with great economic value. China has introduced it from Oceania to control the scale insect. Some beetles have medicinal value, among which the more widely used ones are: the genera of spot, green, bean, and short winged beetles in the family Ranunculaceae. Their adult insects can secrete zeaxanthin (also known as spot sting), which has been used in China to treat certain cancers in recent years; The dried product of the purple dung beetle in the family of dung turtles has functions such as calming, breaking down blood stasis, relieving pain, attacking toxins, and promoting bowel movements.

Some species of Coleoptera are important pests in agriculture, forestry, fruit trees, and horticulture, or have become global pests in various storage and human habitats due to commercial transportation and other reasons. The important species in China include the trench borer and the slender breast borer, which damage seeds, tubers, and seedlings in the soil. The larvae of the superfamily of scarab beetles are commonly known as grubs, and they are also important underground pests. In China, the genera of Yili scarab beetles and Toothed Clawed Claw scarab beetles cause serious damage. Important species in the longhorn beetle family include the domesticated longhorn beetle, the double barred spruce longhorn beetle, and the sugarcane root longhorn beetle, which cause damage to timber, trees, fruit trees, or economic crops in China. The adults and larvae of the leaf beetle superfamily are herbivorous, and important species in China include the rice mud beetle and rice iron beetle that harm rice, and the malignant leaf beetle that harms citrus. The potato beetle is a major pest of potatoes in Europe and North America, and is an important international quarantine object.

In the superfamily of elephant pests, China has corn weevils, rice weevils, and grain weevils, which are destructive species among warehouse pests that harm food and seeds; Sweet potato weevils are important pests of sweet potatoes. The cotton bollworm, which seriously damages cotton in North America and Central America, is an important international quarantine target. Among warehouse pests, the grain spot bark beetle of the family Trichomycteridae harms grains, beans, peanuts, processed oil plants, and animal food. Its larvae have strong drug resistance and are important international quarantine objects. In addition, the silkworm bean weevil and pea weevil of the bean weevil family are also important warehouse pests and quarantine objects in China. Yellow mealworms, black mealworms, miscellaneous grain thieves, and red grain thieves in the family Pseudostellaridae are all important grain storage pests.