Order Coleoptera: Beetles
Beetles belong to the order Coleoptera, it means 'sheath winged',
as the front wings are hardened and protect the thin hind wings that are folded
underneath and used for flying. One of the key charcateristics shared by the
Coleoptera is that the front wings meet in a straight line down the center of
the body. They have chewing mouthparts and complete metamorphosis.
The example shown here is a white grub which will become a pupa
on its way to emerging from the soil as an adult Japanese beetle. The white grub
stage feeds on roots of grasses, while the adult feeds on the leaves, flowers,
and fruits of various plants. This is a good example of complete metamorphosis.
Note that with complete metamorphosis, there are not wing pads developing on
the outside of the larva.
Kentucky Examples in the Order Coleoptera
This is the margined blister beetle. In this photo you can see
how the front wings meet in a straight line down the center of the back. Blister
beetles get their name from the habit of 'leaking' a caustic fluid
from their leg joints when disturbed. In Kentucky, blister beetles can be a
problem for hay producers as crushed beetles in the seasoned hay are toxic to
This is a typical tiger beetle. As you can see from the legs,
tiger beetles are swift runners and have mandibles to capture prey. Many of
the tiger beetle species are brightly colored like this one.
This is a metallic wood boring beetle. These beetles are part
of the larger group of wood borers that also includes longhorned beetles. The
larvae of these are referred to as flat head borers and commonly leave characteristic
'D' shaped emergence holes in the bark of trees. The borers tunnel
in the cambium of the tree and may girdle and kill trees. An accidentally introduced
species in this same family is the emerald ash borer which is destroying ash
trees in parts of Michigan, Ohio and Indiana.
This is one of the more unusual species in Kentucky, the giant
stag beetle. The male (pictured above) has enlarged mandibles which are used
to fight other males. Stag beetles are commonly attracted to lights at night
near wooded areas.
Weevils, sometimes called snout beetles, have their mouth at the
end of a long beak. Although this may appear as sucking mouthparts, the weevil
has small, chewing mandibles at the end of the snout. The insect pictured above
is the larger chestnut weevil.
This is a lightningbug (note that this is written as one word,
because it is not a true bug). Lightningbugs signal among the sexes at night
using specific flashing patterns. Light is produced in a special organ at the
tip of the abdomen.
The beetle pictured above is a type of longhorned beetle, they
are named for the very long antennae. The larvae of many of the longhorned beetles
are borers of trees and shrubs.
Updated November 2005