|
Overview | |
The members of this large group of sucking insects exhibit considerable diversity both in
body size (1/2 mm - 20 cm) and number of species (32,000). All homopterans are plant
feeders, with mouthparts adapted for sucking plant juices from a variety of plants.
Many homopterans cause problems by destroying cultivated plants such as fruit trees and
grain crops; other homopterans carry diseases. A few homopterans provide secretions or
other products that are beneficial to humans. (Encyclopaedia Britannica, 1973)
|
|
|
Identification | |
Majority of homopterans range in body size from four to twelve centimeters, but there are
some scale insects that are only a half of a centimeter long and cicadas that can grow to
about eight centimeters long. The most distinctive features of homopterans are the beak
and the wings. The rigid beak consists of a two pairs of stylets: mandibles and the maxillae.
The mandibles pierce the plant tissue while the maxillae form two conducting tubes, one for
food and the other for saliva. (Encyclopaedia Britannica, 1973) The forwings are usually
pigmented or transparent, and they can be slightly thickened and waxy in some species. The
hindwings are always membranous. At rest, they are held over the body in a rooflike manner with the tips
slightly overlapping. Also, homopterans tend to have extremely complex digestive tracts, which
form filter chambers in most groups. Other features in homopterans are generally similar to
those of other insects. (Encyclopaedia Britannica, 1973)
|
|
|
Names | |
|
|
|
Phylogeny | |
| Taxonomic Category
| Scientific Name
| Common Name
|
| Phylum
| Arthropoda
| Arthropods
|
| Class
| Insecta
| Insects
|
| Order
| Homptera
| Aphids & Whiteflies
|
|
|
|
|
Photographs |
- Scale insect photographs -- Systematic Entomology Laboratory, United States Department of Agriculture
| 
|
| Species: Prosapia bicincta Photo Copyright by Drees
| Species: Tibicen prob. lyricen Photo Copyright by Division of Plant
Industry, Florida Department
of Agriculture & Consumer
Services
|
| 
|
| Species: Aphis nerii Photo Copyright by Drees
| Dictyopharid Planthopper Photo Copyright Troy Bartlett
|
|
|
|
Geographic distribution | |
Homoptera are distributed throughout the entire globe, but the relative numbers of individual
species vary in a given locale. The abundance of any species depends upon many things, but
most importantly the availability of food plants. Mainly, those species that are commonly
considered pests (such as greenbugs and potato leafhoppers) develop large populations because
they are able to feed on large supplies of cultivated crops. Large populations of homopterans
usually are equated to heavy plant losses. (Encyclopaedia Britannica, 1973)
|
|
|
Natural history | |
Plant sap,which contains much water, is what sustains most homopterans because they need
it in order to obtain sufficient nutrients. There is a filter chamber in the gut that
excretes excess water, sugar, waste, and "honeydew." Honeydew is attractive to other
insects that subsist on sweetened nutrients. Ants, for example, "farm" certain species
of aphids by carrying them to their food plants and feeding on the produced honeydew.
The feeding habits of homopterans, which determine the type of habitat in which they live,
are usually species specific.
Homopterans are the target of many predaceous insects. For example, ladybugs feed on
aphids and can consume thousands of them in a few months. Dryinid wasps, which lay eggs
in the bodies of their hosts, parasitize various leafhoppers and treehoppers. A species
of wasp commonly called the "cicada-killer" will place a stung and paralyzed cicada in a
burrow and then lay eggs on it. the larvae will hatch and grow on the cicada until they
become adults.
Most homopterans reproduce sexually and are egg-laying. Eggs are laid on or in the
preferred food plant so that the hatching larvae have a readily available food source.
Metamorphosis is typically gradual, with immature stages resembling the adults but
lacking wings. Life cycles are usually short.
Some homopterans have unique life cycles. For example, aphids lay that all hatch into
females, which in turn give live birth to more females and then later to males. Mating
occurs, and then the cycle starts over again. Scale insects overwinter as eggs under
the scale covering of the female. The newly hatched crawl off in search of food, and
then within a few days they molt their legs and antennae and produce a hard scale. The
males then grow in size and form wings during the final stage; the females increase in
size but never develop wings.
The most popular homopteran is the cicada. The female lays here eggs in the bark of
deciduous trees, and the young hatch and burrow underground, spending the next thirteen
or seventeen years feeding on the roots of trees. At maturation, they emerge from the
ground, climb onto the sides of trees, and then molt a final time before becoming an
adult. (Britannica.com) It is easy to spot cicada "shells" on the bark of trees.
When I was young, my brother and I used to scare our little sisters by sticking cicada shells on our noses.
Members of the Homoptera cause damage to domesticated plants in several ways. Plants
may be harmed directly by feeding, such as when the saliva of leafhoppers destroys the
chlorophyll in leaves and causes the leaves to die. Intense feeding by homopterans can
cause stunted growth in the target plants. Cicadas damage trees when they make slits
in the branches for egg deposition, and some homopterans carry pathogens of plant diseases.
Although they can cause great damage, homopterans can be benefitial. For example, the
"Indian lac insect" is commercially important because the lac it secretes can be melted
off twigs, refined, and used to make shellac and varnish.
(Britannica.com)
|
|
|
How to encounter | |
Generally, homoptera can be found in grasslands, forests, crop fields, and even on ornamental plants.
Most of the common sampling techniques (searching, beating, sweeping and many forms of trapping)
have been used to sample Homoptera. In uniform host plant scenarios, sweeping and beating are
the simplest sampling methods. Pan traps are also helpful, but present some biases, such as
capturing non-target insect species. There are many traps that can be used, like suction traps.
|
|
|
Links to other sites | |
|
|
|
References |
- "Homoptera." The New Encyclopaedia Britannica: Macropaedia. 15th ed. 1973.
|
|
|
Acknowledgements |
- Stephen Boyd, Scientific Illustration Major, University of Georgia, Athens
- Special Thanks to: Donald Lewis, Drees at Texas A&M, The Florida Department of Agriculture & Consumer
Services, Troy Bartlett, Robert Foottit at the Ecological Monitoring and Assessment Network, The
University of Delaware, and John L. Foltz's Entomology class at the University of Florida.
- Thanks to Sabina Gupta, Denise Lim, and Dr. John Pickering
for technical and web support in developing this page.
|
|
| Supported by | |
Updated: 2023-06-01 22:48:28 gmt
|
