In the photo on the right: a shield bug. Of course the word bug is often used for all
kind of small critters, but here we are dealing with true bugs. True bugs are often
mistaken for beetles - and they have a superficial similarity. But the Latin word for bugs,
Heteroptera, indicates the difference: ( hetero: different, ptera:
wings) refers to the fact that the front pair of wings is only partly hardened, the
other part is membranous. This is in contrast to beetles, Latin: Coleo-ptera, in
which the front wings are completely hardened and lie against each other, the elytra,
(Greek Koleos, sheath), so that there is always a seam across the middle. A bug
crosses its forewings over each other, so that seam is not there. Instead
there is a, more or less clear, 'figure X' on the back - see the photo on the
right.
The classification has not yet been determined. Heteroptera fall under the larger
order Hemiptera or half- (= hemi)wings, which again points to this characteristic. To
make it a bit more complex: the wing length of the second pair of wings is sometimes also
different in one and the same species of bug: there are macroptere individuals with
entire wings, microptere with small ones and aptere without wings (a-: not,
none).
Furthermore, bugs have mouth parts fused into a snout, hence the name
Rhynchota (Rhyno = nose, snout). This tubular snout, called proboscis or
rostrum, has a razor-sharp point and is carried horizontally under the head when at
rest. When feeding, the snout is folded forward and the plant or prey is pierced, digestive
saliva is injected and the nutritious juices are sucked up. Most bugs are plant suckers,
some can cause quite a bit of damage. Humans are also sometimes 'prey', such as in
the case of the infamous bed bug.
Bugs have scent glands for defense, which secrete a malodorous fluid with a bad taste (and
possibly paralyzing properties). Most people find the smell disgusting, so some species are
called 'stink bugs'.
Most bugs have a flat shape. There is usually an imperfect metamorphosis, i.e. the
young animals (nymphs) look very much like the older ones, although they often do not
yet have wings.
WHAT IS A WATERBUG ?
Water bugs (Hydrocorisae) do not form a real biological group. It is a collection of very different groups of bug families, adapted to life in and on the water. A group lives on the surface (water skaters, pond crawlers, stream crawlers) and a group in the water (backswimmers, water boatmen, water scorpions, stick bugs, swimming bugs). Just take a look at the bug gallery to see how different they are!