Insect, any member of the class Insecta, the largest class of phylum Arthropoda. Insects have segmented bodies, jointed legs, and exoskeletons. They are distinguished from other arthropods by their body, which has three major regions: the head, the three-segmented thorax, and the many-segmented abdomen.

Insects are members of a larger group called the arthropods. This group also includes spiders, ticks, centipedes, lobsters, and crabs. Like all arthropods, insects have a body that is divided into segments, or sections.

Their large populations and great variety are related to their small size, high reproduction rate, and abundant food supplies. Insects play many important roles in nature, including decomposition, soil formation, and pollination. Certain insects can be of direct benefit to humans.

Feb 15, 2025 · Spider, any of more than 46,700 species of arachnids that differ from insects in having eight legs rather than six and in having the body divided into two parts rather than three. All spiders are predators, feeding almost entirely on other arthropods, especially insects.

Insect bodies have three segments: head, thorax (which bears three pairs of legs and usually two pairs of wings), and many-segmented abdomen. Many species undergo complete metamorphosis. There are two subclasses: Apterygota (primitive, wingless forms, including silverfish and bristletails) and Pterygota (more advanced, winged or secondarily ...

Insect - Adaptation, Metamorphosis, Diversity: Most insects begin their lives as fertilized eggs. The hatching of young larvae is achieved in several ways. Insects undergo one of two types of metamorphosis: incomplete or complete.

Many insects are invaluable as predators on insects that are pests to humans. In the same way, plant-eating insects are often valuable for their destruction of weeds. Insects that burrow in the earth improve the physical and chemical condition of the soil.

When a click beetle is touched, it falls on its back and plays dead. To right itself the click beetle bends its head and thorax forward, hooking a spine into a notch on the abdomen. When the spine is released, it makes a click, and the beetle is hurled into the air.

Jan 17, 2025 · Arachnid, any member of the arthropod group that includes spiders, daddy longlegs, scorpions, and mites and ticks, as well as lesser-known subgroups. Some arachnids transmit diseases to humans and plants. Learn more about the physical features, behavior, natural history, and evolution of arachnids.

Jan 31, 2025 · fly, (order Diptera), any of a large number of insects characterized by the use of only one pair of wings for flight and the reduction of the second pair of wings to knobs (called halteres) used for balance. The term fly is commonly used for almost any small flying insect.