Coleoptera (Beetles)

Beetles, insects of the Coleoptera order, have hardened front wings called elytra, setting them apart from other insects. Coleoptera is the largest order with around 400,000 species, making up nearly 40% of insects and 25% of all animal species.

Beetles inhabit nearly every environment except the sea and polar regions. They play various roles in ecosystems: feeding on plants, fungi, breaking down debris, and preying on invertebrates. Some, like the Colorado potato beetle, are agricultural pests, while others, like ladybugs, help control pests. Unique species like fireflies use light for communication and mating.

Beetles generally have a hard exoskeleton, although rove beetles have short elytra and blister beetles have softer ones. Their anatomy is mostly uniform but includes adaptations like water beetles trapping air under elytra for diving.

As holometabolans, beetles undergo complete metamorphosis, changing significantly from hatching to adulthood after a pupal stage. Some, like stag beetles, show sexual dimorphism with males having large mandibles for fighting. Many beetles are brightly colored to warn of toxicity, while some mimic such insects harmlessly. Others, especially in sandy areas, have excellent camouflage.

Source: Wikipedia