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Overview | |
Hemiptera, known as True Bugs, is a very large and diverse order. They are found all over the world;
there are few habitats without a Hemiptera adapted to living there. There are 80,000 described species
in 37 families. The order is divided into three suborders: Geocorizae (terrestrial bugs), Amphibicorizae
(semiaquatic or shore-inhabiting bugs), and Hydrocorizae (aquatic bugs). Hemiptera are also important
in agriculture, known to cause direct damage to plants by herbivory and indirectly by transporting
diseases (Dooling, 1991). Predatory Hemiptera have also been used in agricultural systems to control
pests (Coll and Ruberson, 1998).
Called the true bugs, insects in the order hemiptera have a particular structure
of the front wings from which the order gets its name
- Basal portion of the front wing is thickened and leathery
- Apical portion is membranous (this type of wing is called hemelytron, or hemelytran if single)
- Hind wings are completely membranous and shorter than the front wings
- Wings at rest are held over the abdomen with membranous tips overlapping
Other characeristics of Hemiptera include:
- piercing-sucking mouth parts
- Mouth part in form of segmented beak arising from front part of the head and extending back
along the ventral side of the body at times as far as the base of the hind legs
- Antennae are fairly long and contain four to five segments
- Compound eyes are usually well developed
- Many have glands secreting unpleasant odor
- Well developed wings in general
- Some are wingless
- Eggs cases may be layed on plants or sometimes just dropped
- Simple metamorphosis with mostly five nymphal instars
- Most species are terrestrial but some are aquatic
- Predacious ones are beneficial to man
- Some may serve as disease vectors
Hemiptera means "half-wings", referring to how the wings overlap and how they are made of two dissimilar halves. (Slater and Baranowski, 1978)
Common Name: True Bugs
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Identification | |
There is much diversity in the morphology of the order. All Hemiptera have large compound eyes.
The second pair of eyes are ocelli. The antennae have four or five segments. Mouthparts have
been adapted for piercing or sucking. The mandibles and maxillae are modified as needle-like
stylets. Each stylet has two canals: one for delivering saliva and one for sucking fluid. (Gullan
and Cranston, 1994). The thorax is divided into three segments, each with a pair of legs. The
front pair of wings is found on the mesothorax and the second pair is found on the metathorax.
Wings can be reduced or absent. The legs are modified for swimming or predation. The abdomen is
made up of nine or ten segments. Segments 8 and 9 are modified to form the genitalia, which are
used in identification (Slater and Baranowski, 1978).
Mouthparts highly modified for piercing and sucking. The mandibles and maxillae form 4 piercing
stylets within the beak (labium), which arises form the front of the head. The antennae are 4-5
segmented. Nymphs have external wingpads (sometimes absent) and unsegmented tarsi. Adults
have the forewing (hemelytra) basally thickened and apically membranous. The hindwings are fully
membranous. Some species may be brachypterous or apterous, if apterous the tarsi are 2-3
segmented.
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Phylogeny |
| Taxonomic Category
| Scientific Name
| Common Name
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| Phylum
| Arthropoda
| Arthropods
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| Class
| Insecta
| Insects
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| Order
| Hemiptera
| True Bugs
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Photographs | |
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Geographic distribution | |
Hemiptera are found in a diversity of habitats all over the world (Slater and Baranowski, 1978).
There are 80,000 species and more to be named. Approximately 11,000 species are found in North America (Earthlife).
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Natural history |
Hemiptera undergo incomplete metamorphosis. The egg is inserted into plant tissues,
bark, or soil. The egg is usually a simple elliptical shape; however, some families have
unusually-shaped eggs. For example, Pentatomidae have small barrel-shaped eggs. The eggs
of Reduviidae have spines and filaments (Dooling,1991). The nymph undergoes five instars
(time between molts). After each instar, there is an increase in size. Wing pads become
visible and scent gland develop for protection (Dooling, 1991). The adults feed actively
on plants and other insects. They live on leaves (terrestrial) or on the surface of the
water (aquatic) (Dooling, 1991). Hemiptera are also known for their symbiotic relationships
with ants. Phloem-feeding Hemiptera excrete a sugary, energy-rich substance known as
“honeydew”. Ants “herd” the aphids and provide protection for them in return
for the honeydew. The ants may also build soil shelters over aphid colonies and store
Hemiptera eggs until they hatch. (Dooling, 1991).
Adults breed mostly in the spring and early summer. Many species produce sound by stridulating to
communicate between the sexes. Mating takes place in the normal habitat for the species. Eggs are
normally attached to vegetation or other objects, some species guard the eggs. The eggs hatch
quickly and the nymphs grow quickly through 5 (rarely 4) instars during the summer. The adults
overwinter by hibernating or they may remain active. Most species are univoltine in our area.
- Trophic Roles
The family Corixidae contains many species that feed on algae, or even as collectors as well as
predators. All remaining aquatic and semiaquatic bugs are primarily predators as nymphs and adults.
They use the piercing mouthparts to penetrate the prey, inject hydrolytic enzymes and suck out the
juices. Many have raptorial forelegs to help handle the prey. Many are very fierce taking large prey
and causing painful bites. Semiaquatic species feed from the surface or just below the surface.
Purely terrestrial bugs may be predators, herbivores or even parasites.
- Communities
Most diverse in warm, heavily vegetated, shallow, lentic or slow lotic waters. Corixids are most
specious and show more pronounced habitat preferences. Most bugs come to the surface
periodically for air. Some water striders live on the open oceans.
- Economic Importance
Terrestrial species may be very important agricultural pests, pest controlling predators, or vectors of
disease. Aquatic species help control nuisance insects, some are used for human or pet food, some
are bitting nuisances, some may feed on hatchery fish, only corixids are normally fed upon by fish.
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How to encounter | |
Using a short-handled net, Hemiptera can be collected by sweeping back and forth among
herbaceous vegetation. The net can also be placed over the plant and shaken. Malaise traps
and pitfall traps do not work well in collection of Hemiptera. In terrestrial collection,
individual leaves can be examined. In aquatic collecting, nets can be used to sweep the
top of the water (Dooling, 1991).
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Links to other sites | |
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References |
- Coll, Moshe and John R. Ruberson (eds.). Predatory Hemiptera: Their Ecology and Use in Biological Control. 1998: Entomological Society of America, Maryland.
- Dooling, W.R. The Hemiptera. 1991: Oxford University Press, New York.
- Gullan, P.J. and P.S. Cranston. The Insects: An Outline of Entomology. 1994: Chapman and Hall, London.
- Slater, James A. and Richard M. Baranowski. How to Know True Bugs. 1978: William C. Brown Publishers, Iowa.
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Acknowledgements |
- Kari McLaughlin, Ecology Major, University of Georgia, Athens
- Thanks to Sabina Gupta, Denise Lim, and Dr. John Pickering
for technical and web support in developing this page.
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| Supported by | |
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Following modified from University of Guelph Insect Collection
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