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The
Diversity of The World of Life
True
Insects (Insecta)
True
Bugs etc.
(Hemiptera)
Representatives
True
Bugs
Cicadas,
or Locusts
Hoppers:
Treehoppers; Froghoppers, or Spittlebugs; Leafhoppers;
& Planthoppers
Psyllids,
or Jumping Plantlice
Whiteflies
Aphids,
or Plantlice
Scale
Insects, including Mealybugs
Biology
APPROXIMATE NUMBER OF KNOWN SPECIES WORLDWIDE
60,000
DESCRIPTION
These
insects vary greatly in size, from very small to very large.
The
antennae are short to long, rarely absent. Many species (other than
true bugs) are jumping; and several species (such as mealybugs, woolly
aphids, or spittlebugs) live within waxy, cottony, or foamy secretions.
The
mouthparts of all these insects are a piercing-sucking beak. In true
bugs, they are long, attached to the front of the head, and held under the
body; in the other insects of this order, the mouthparts are typically
short and are attached to the rear of the underside of the head.
Except for
lace bugs (small, flat bugs with lace-textured wings), water-strider and
similar aquatic bugs (narrow bugs without wings), and bed bugs (small,
flat, reddish-brown bugs without wings), true bugs have forewings that are
leathery at the base but membranous (and overlapping) at the tip.
The smaller, completely membranous hindwings are covered by the
forewings, held flat over the abdomen at rest.
Cicadas
are large. The antennae are short. There are two pairs of membranous wings, held roof-like over the
body at rest. Male
cicadas typically buzz (or tick), as for species-specific mating- or
alarm-calls.
The
various families of hoppers are typically small. The antennae are
short. There are two pairs of wings -- the forewings veined
and somewhat leathery, the hindwings membranous -- held roof-like over
the body at rest. Treehoppers are humpbacked or thorn-shaped;
froghoppers, rather frog-shaped; leafhoppers and planthoppers, typically wedge-shaped.
Psyllids
are small. The antennae are long and threadlike. There are two
pairs of wings -- the forewings membranous, or veined and leathery; the
hindwings membranous -- held roof-like over the body at rest.
Psyllids, also called jumping plantlice, indeed jump.
Whiteflies
are small. The antennae are long and threadlike. There are two pairs of membranous wings, held roof-like over the
body at rest and covered with a typically white powder.
Aphids
are small and plump, with a pair of small tubes at the tail-end of the
body. The antennae are long and threadlike. There may be no
wings or two pairs of membranous wings, held
roof-like over the body at rest.
Scale
insects are typically small. Adult male scale insects have fairly
long antennae; one pair of wings, with few veins; and one (rarely two) thin
tails. Adult female scale insects are antennae-less, legless, wingless, and found
under a waxy or scaly covering.
METAMORPHOSIS
The nymphs of true bugs and most of the other insects in
this group look like small adults, although with small or no wings.
However, many of the remaining insects in this group have very
complex life histories, with very different body forms during different stages
of their lives. Typically, the hatchlings are active; but later
young are inactive,
often scalelike, something like the "pupae" of higher insects. Males,
often produced only at the end of the growing
season, often differ in form from the females.
"Parthenogenesis" (development of eggs without
fertilization) is common amongst aphids, some of which also give birth to
already hatched young -- aphids can build-up huge populations very
quickly, as on farms or in gardens.
HABITATS
A few true bugs
live in saltwater (especially in marshes), many live in freshwater, most
live on land plants, and a few live as parasites on us vertebrates.
Each of the other species usually lives on a particular
part of a select few species of plants.
Some insects in this order cause plants to form swollen
"galls", in which the insects live.
Some insects in this order live in the soil (Cicada nymphs
may spend years underground, feeding on roots).
Spittlebug nymphs live within a mass of foamy bubbles they
make on their food plants, and scale insects live under a scaly or waxy
covering they secrete.
FOODS
Many true bugs
suck sap from plants, many prey on other insects, and a few suck the blood
of us vertebrates.
The other insects in this group suck sap, through their
piercing-sucking beak, typically on shoots but sometimes on roots and
typically on a species-specific range of plants.
DAMAGES/BENEFITS
Many crops are withered, deformed, galled, discolored,
stunted, and/or killed by the many plant-feeding pests in
this order -- the damage caused directly, by sucking sap from the plants,
and/or indirectly, by infecting the plants with viruses that cause
diseases.
Sweet "honeydew" produced by many of the insects
in this order often attracts ants, which may tend the insects as
"dairy cows"!
Cicadas and treehoppers sometimes damage trees and shrubs
by laying eggs in twigs.
Many bugs (such as some stink bugs) are beneficial
predators of damaging insect pests; some bugs (such as ambush bugs) are
damaging predators of beneficial insects, such as honey bees visiting
flowers; and some bugs (such as bed bugs or kissing bugs) are
bloodsucking, irritating, sometimes disease-carrying pests of domestic
animals or us human beings.
Finally, certain scale insects produce valuable
secretions, such as certain dyes or the raw material of commercial shellac.
True
Insects (Insecta)
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