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Homoptera
Life   Insecta

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
Scientific source:

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.

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Updated: 2017-10-23 14:35:22 gmt
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