Beetles are the most diverse order of living organisms and their
numbers are extraordinary with more than 350,000 named species
that represent about 40% of all insects and 30% of all animals.
There are at least six times as many beetles as
species and 90 times more than the number of all mammals.
The order is usually divided into
four suborders and about 150 families.
Polyphaga is by far the largest
suborder, containing 85% of the known species, including rove
beetles, scarabs, stag beetles, metallic wood boring beetles,
click beetles, fireflies, blister beetles, mealworms, ladybirds,
leaf beetles, longhorn beetles, and weevils.
Perhaps the single most important
factor in the success of the Beetles is the development of the
elytra or armored forewings that are leathery and hard, they are
not used in flight but are a sheath that covers the more delicate
flying wings when they are not in use. In Flight, the elytra are
held perpendicular to the body and are used as airfoils.
Beetles live in almost every
conceivable terrestrial and freshwater habitat and even in some
marginal marine ones.
Many species live in fresh water,
either in the larva stage or in both larval and adult stages.
Many adults have ventral patches of fine setae that trap air
bubbles for use in breathing under water.
Most species of beetles probably
eat living plant tissue, but many feed largely on decomposing
material. Most are predators.
Beetles are of immense ecological
and economic importance. Many are vital in the cycles of
decomposition of plant and animal matter. Others are predators
of insects and other invertebrates that damage crops and other
On the other hand many beetles
feed on the foliage and roots of plants, causing much damage to
crops and they can kill huge tracts of valuable forests in a short