Everything about Hemiptera totally explained
Hemiptera is an
order of
insects, comprising around 80,000
species of
cicadas,
aphids,
planthoppers,
leafhoppers,
shield bugs, and others, collectively known as the
true bugs. They range in size from 1
mm to around 15
cm, and share a common arrangement of sucking
mouthparts .
Characteristics
The defining feature of hemipterans is their possession of
mouthparts where the
mandibles and maxillae have evolved into a
proboscis, sheathed within a modified labium to form a "beak" or "
rostrum" which is capable of piercing
tissues (usually plant tissues) and sucking out the liquids — typically
sap.
The name "Hemiptera" is from the
Greek hemi ("half") and
pteron ("wing"), referring to the
forewings of many hemipterans which are hardened near the base, but membranous at the ends. These wings are termed
hemelytra (singular:
hemelytron), by analogy with the completely hardened
elytra of
beetles. They may be held "roofwise" over the body, or held flat on the back, with the ends overlapping. The hindwings are entirely membranous and are usually shorter than the forewings.
The
antennae in Hemiptera are typically five-segmented, although they can still be quite long, and the tarsi of the
legs are three-segmented or shorter .
Although hemipterans vary widely in their overall form, their mouthparts (formed into a "rostrum") are quite distinctive; the only orders with mouthparts modified in a similar manner are the
Thysanoptera and some
Phthiraptera, and these are generally easy to recognize as non-hemipteran for other reasons. Aside from the mouthparts, various insects can be confused with hemipterans, including
cockroaches and
psocids, both of which have longer many-segmented antennae, and some
beetles, but these have fully-hardened forewings which don't overlap .
Classification
The present members of the order Hemiptera were historically placed into two orders,
Homoptera and Heteroptera/Hemiptera, based on the differences in wing structure and the position of the rostrum. These two orders were then combined into the single order Hemiptera by many authorities, with Homoptera and Heteroptera classified as
suborders. The order is presently more usually divided into four or more suborders, after it was established that the families grouped together as "Homoptera" are not as closely related as had previously been thought (see
paraphyly).
Auchenorrhyncha contains the
cicadas,
leafhoppers,
treehoppers,
planthoppers, and
froghoppers. The 12,500 species in the suborder
Sternorrhyncha are the
aphids,
whiteflies and
scale insects. The suborder
Coleorrhyncha (comprising the single family Peloridiidae), contains fewer than 30 species of
Gondwana-distributed bugs, and is sometimes grouped with the Heteroptera (to form the suborder
Prosorrhyncha).
Heteroptera itself is a group of 25,000 species of relatively large bugs, including the
shield bugs,
seed bugs,
assassin bugs,
flower bugs and the water bugs (see below).
The closest relatives of hemipterans are the
thrips and
lice, which collectively form the "Hemipteroid Assemblage" within the
Exopterygota subclass of the Class
Insecta .
Life cycle and ecology
Hemipterans are
hemimetabolous, meaning that they don't undergo
metamorphosis between a
larval phase and an
adult phase. Instead, their young are called
nymphs, and resemble the adults to a large degree, the final transformation involving little more than the development of functional wings (if they're present at all) and functioning sexual organs, with no intervening
pupal stage as in
holometabolous insects. Hemiptera is the largest insect order that's hemimetabolous; the orders with more species all have a
pupal stage (
Lepidoptera,
Coleoptera,
Diptera and
Hymenoptera).
Many aphids are
parthenogenetic during part of the life cycle, such that females can produce unfertilized eggs, which are
clones of themselves.
Most hemipterans are phytophagous, feeding on plant sap, such as
aphids,
scale insects and
cicadas. Most of the remainder are
predatory, feeding on other insects, or even small vertebrates. A few, however, are parasites, feeding on the blood of larger animals. These include
bedbugs and the
kissing bugs of the family
Reduviidae, which can transmit potentially deadly
Trypanosoma infections .
Several families of Hemiptera are
water bugs, adapted to an
aquatic lifestyle, such as the
water boatmen and
water scorpions. They are mostly predatory, and have legs adapted as
paddles to help the animal move through the water. The "pondskaters" or "water striders" of the family
Gerridae are also associated with water, but use the
surface tension of standing water to keep them above the surface; they include the genus
Halobates which is the only group of insects to be truly
marine .
Conversely, some predatory hemipterans are themselves biological pest control agents, such as various
nabids(External Link
) and even some members of families that are primarily phytophagous, such as the genus
Geocoris in the family
Lygaeidae(External Link). Other hemipterans have positive uses, such as in the production of the dyestuffs
cochineal and
crimson, or
shellac.
Further Information
Get more info on 'Hemiptera'.
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