Insects are one of the most diverse groups of animals on Earth, with over 1 million described species. They have adapted to live in almost every terrestrial habitat, and their success is due in part to their small size and ability to fly. Insects play important roles in ecosystems as pollinators, predators and prey, and as decomposers. They also provide humans with a source of food (e.g., honeybees) and fiber (e.g., silkworms), and are used for pest control (e.g., ladybugs).
Insects are arthropods, meaning they have segmented bodies with jointed appendages. The majority of insects have wings, which evolved from ancestral wingless ancestors. Wings allow insects to fly, which gives them a great advantage in dispersal and escape from predators. Insect wings are typically covered in scales, which can be brightly colored or patterned to provide camouflage or mimic other organisms (e.g., leaves).
The body of an insect is divided into three main regions: the head, thorax and abdomen. The head houses the brain and sense organs, while the thorax contains the legs and wings (if present). The abdomen is where the guts are located, as well as reproductive organs in adults. Most adult insects have just two pairs of wings – one pair for flying forwards and another pair for steering – but some groups (e.g., beetles) have lost their wings altogether during evolution. Insect larvae typically look very different from adults, often having more leg-like appendages or no wings at all; this allows them to move around easily while they feed on plants or animals before transforming into their winged adult form through metamorphosis.
The vast majority of insects feed on plants, using their mouthparts to puncture plant tissue and suck out the juices within. Some groups however are specialized herbivores that eat specific parts of plants – e.g., caterpillars that only eat leaves or weevils that bore into fruit or seeds – while others are generalists that will eat anything they can find (including other insects!). Carnivorous insects use their powerful mandibles to catch prey items; many larger carnivores will even take vertebrate prey such as lizards or rodents if given the chance! Predatory behavior isn’t limited to carnivorous species though; many ants also hunt other insects for food using venomous stings delivered by their long abdomens