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HEMIPTERA [Latest Classification] HEMIPTERA = Photos-1, Photos-2 Principal Families Further
Description References Introduction Hemiptera.-- Most Hemiptera are
phytophagous, but a large number of species in the more important families
show a strong tendency toward entomophagy.
In several instances of independent origin this has reached the point where
plant feeding is abandoned entirely and predation is obligatory (Clausen
1940/1962). This occurs among both
aquatic and terrestrial species.
Although these species show certain preferences in choice of food,
records exist to indicate that the majority is more or less omnivorous. The life histories and behavior of
many British Hemiptera and descriptions of immature stages were recorded by
Butler (1923). These included all the
predaceous groups as well as the wholly phytophagous representatives of the
order. Elson (1937) made a
comparative study of the anatomy of the order in order to correlate structure
with food habits. He found that the
predatory forms possess both external and internal modifications for
predation. The front legs are
frequently adapted for capturing and holding prey. The rostrum is usually short and stout, either straight or
curved, but never angular, and capable of movement in all directions. The alimentary tract is longer than in
other forms, and the salivary glands produce an alkaline secretion which is
injected into the host's body, acting as a poison or paralyzing agent. Feeding by predaceous nymphs and adults is
usually with the rostrum held in a horizontal plane to the body, while in
strictly phytophagous forms it is held at right angles to the plane. In addition to the families that
will be discussed separately, Clausen (1940) noted a few such as Phymatidae
and Enicocephalidae that are relatively small groups inhabiting foliage and
flowers and feeding on a variety of insects.
Members of the superfamily Gerroidea are mainly aquatic and the nymphs
and adults of Gerridae, Vellidae, Naucoridae, Nepidae, Belostomatidae,
Notonectidae feed principally on insects and a variety of smaller animal life
found in ponds and streams. Some of
the larger forms even prey on tadpoles and small fish. The Ochteridae and Nerthridae are littoral
in habit and feed on such insects and other small animals that frequent the
muddy margins of ponds and streams.
The true bugs include over 70,000 identified species of
cicadas, aphids, planthoppers, leafhoppers, shield bugs, etc. Their size is
from 1 mm. to 17 cm. They all
have sucking mouthparts. The mouthparts where the
mandibles and maxillae have become modified into a proboscis, enveloped in a
sheath within a labium to form a rostrum, which is used for piercing and
sucking tissues of plants or animals. The forewings of are
either membranous, or partially hardened.
The name "Hemiptera" stems from the Greek hemi;
"half") and pteron; "wing"), referring to the forewings of many
species that are hardened near their bases but are membranous at the tips (=
hemelytra). The forewings may be held
over the body (typical of or held flat on the back, with the ends
overlapping. The hindwings if present
are entirely membranous and mostly shorter than the forewings. The antennae usually have five segments,
though they may still be long, and the tarsi of the legs are three-segmented
or shorter. Although there is a large variation in form, the mouthparts are quite
characteristic. Hemiptera are
hemimetabolous, and ther immatures are referred to as nymphs. These resemble adults. Hemiptera is the
largest hemimetabolous insect order. Aphids are usually
hermaphroditic during part of the life cycle, so that females are able
produce unfertilized eggs, that develop into viable individuals. Most species are
phytophagous, feeding on plant juices. Others are predatory, feeding on other
insects, or small vertebrates. A few species feed on the blood of larger
animals. These include bedbugs and the kissing bugs (Reduviidae), which can
transmit potentially deadly Trypanosoma infections. Several families of
Hemiptera have water bugs that are adapted to an aquatic environment,
such as the water boatmen and water scorpions. Most of these are predatory, and have legs which are
modified as paddles to assist in movement through water. The
"pondskaters" or "water striders" (Gerridae) are also
associated with water, but use the surface tension of water to allow them to
"walk" on the surface.
Included is the marine genus Halobates. Many species of are
injurious pests of crops and vegetables, including aphids and scale insects, Some predatory species
are useful as biological pest control agents. Included are species of Nabidae, and some primarily
phytophagous species, such as the genus Geocoris (Lygaeidae). Other
species have been used in the production of the cochineal dyes, shellac and
crimson. = = = = = =
= = = = References: Please refer to <biology.ref.htm>, [Additional references
may be found at: MELVYL
Library] Chinery, M. 1993. Insects of Britain and Northern
Europe 3rd ed.. Daly, H. V., John T. Doyen & Alexander H. Purcell
1998. Introduction to Insect Biology and Diversity 2nd ed.. Oxford
University Press. pp. 320. ISBN 0-19-510033-6. Foltz, J. L. January 23, 2003. "ENY 3005 Families of
Hemiptera". University of Florida.. Green, D. L.
August 10, 2003. "Cottony cushion scale: The pest that launched a
revolution in pest control methods". Hagler, J. "Geocoris spp. Heteroptera: Lygaeidae – Bigeyed Bug".
In Catherine R. Weeden, Anthony M. Shelton & Michael P. Hoffman. Biological Control: A Guide to Natural
Enemies in North America. Cornell University. Mahr, S. 1997. "Know Your Friends: Damsel
Bugs". Biological Control News University of Wisconsin–Madison IV
2. Martin, J. & Mick Webb. "Hemiptera...It's a
Bug's Life" PDF. Natural History Museum. Shcherbakov, D. E.
2000.
"Permian faunas of Homoptera Hemiptera in relation to phytogeography and
the Permo-Triassic crisis" PDF. Paleontological Journal 34 3:
S251–S267. |