Order Coleoptera has the most insect species. Beetles can be found throughout the world and can vary from a millimeter to 75 millimeters in length. They have an open circulatory system that uses fluid instead of blood. Most beetles have two pairs of wings, one pair is hardened and the other pair is membranous. Their antennae are mostly used for their sense of smell. They have spiracles, which are breathing holes on their abdomen. Most beetles feed on plants, but other species are predaceous. Some species are aquatic and have a hard exoskeleton. Some species are sexually dimorphic. This can be seen when males have horns on their head. Most beetles undergo complete metamorphosis. They go through several stages from: the egg, the grub, the pupa, and the adult (also known as an imago). Most beetles have a gland that produces pheromones to attract a mate. Beetles can be found in the fossil record as far back as the Lower Permian. People release beetles to control common pests, for instance, ladybugs are released into gardens to control aphid populations.
No one has provided updates yet.