leafhopper

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Leafhoppers
Adult Two-lined Gum Treehopper (Eurymeloides bicincta: Eurymelinae) demonstrating a symbiotic relationship with meat ants
Scientific classification
Kingdom: Animalia Phylum: Arthropoda Class: Insecta Subclass: Pterygota Infraclass: Neoptera Superorder: Exopterygota/Paraneoptera Order: Hemiptera Suborder: Clypeorrhyncha Superfamily: Membracoidea Family: Cicadellidae Latreille, 1802
Subfamilies
Almost 40, see text

Leafhopper is a common name applied to any species from the family Cicadellidae. Leafhoppers, colloquially known as "hoppers", are minute plant-feeding insects in the superfamily Membracoidea in the order Hemiptera. They belong to a lineage traditionally treated as infraorder Cicadomorpha in the suborder Auchenorrhyncha, but as the latter taxon is probably not monophyletic many modern authors prefer to abolish the Auchenorrhyncha and elevate the cicadomorphs to a suborder Clypeorrhyncha.

Leafhoppers are found all over the world and constitute is the second-largest family in the Hemiptera. They have at least 20,000 described species. The tribe Proconiini of the subfamily Cicadellinae is commonly known as sharpshooters.

Description and ecology

The Cicadellidae combine the following features:

• thickened part of the antennae very short and ending with a bristle (arista)
• two ocelli (simple eyes) present on the top or front of the head
• tarsi made of three segments
• front femora with at most weak spines
• hind tibiae with one or more distinct keels, with a row of movable spines on each, sometimes on enlarged bases
• base of middle legs close together where they originate under the thorax
• front wings not particularly thickened.

An additional and unique character of leafhoppers is the production of brochosomes which are thought to protect the animals and particularly their egg clutches from predation and pathogens.

Nymph of an unidentified Typhlocybinae species

Like other Exopterygota, the leafhoppers undergo direct development from nymph to adult without a pupal stage. While many leafhoppers are drab little insects as is typical for the Membracoidea, the adults and nymphs of some species are quite colorful. Some – in particular Stegelytrinae – have largely translucent wings and resemble flies at a casual glance.

Leafhoppers have piercing-sucking mouthparts, enabling them to feed on plant sap. A leafhoppers' diet commonly consists of sap from a wide and diverse range of plants, but some are more host-specific. Leafhoppers mainly are herbivores but some are known to eat smaller insects such as aphids on occasion. A few species are known to be mud-puddling, but as it seems females rarely engage in such behavior. Leafhoppers can transmit plant pathogens such as viruses, phytoplasmas^[1] and bacteria. Cicadellidae species that are significant agricultural pests include the Beet Leafhopper (Circulifer tenellus), Potato Leafhopper (Empoasca fabae), Two-spotted Leafhopper (Sophonia rufofascia), Glassy-winged Sharpshooter (Homalodisca vitripennis), The Common Brown Leafhopper (Orosius orientalis) and White Apple Leafhopper (Typhlocyba pomaria).

In some cases the plant pathogens distributed by leafhoppers are also pathogens of the insect themselves and can replicate within the leafhoppers' salivary glands. Leafhoppers are also susceptible to various insect pathogens, including Dicistroviridae viruses, bacteria and fungi; numerous parasitoids attack the eggs and the adults provide food for small insectivores.

Systematics

In the now-obsolete classification that was used throughout much of the 20th century, the leafhoppers were part of the "Homoptera", a paraphyletic assemblage uniting the less advanced lineages of Hemiptera and ranked as suborder. The splitting of the "Homoptera" is likely to be repeated for the "Auchenorrhyncha" for similar reasons, as the "Auchenorrhyncha" simply seem to group the moderately advanced Hemiptera regardless of the fact that the highly apomorphic Coleorrhyncha and Heteroptera (typical bugs) evolved from "auchenorrhynchans". Hence, there is a recent trend to treat the most advanced hemipterans as three or four lineages, namely Archaeorrhyncha (Fulgoromorpha if included in "Auchenorrhyncha"), Coleorrhyncha and Heteroptera (sometimes united as Prosorrhyncha) and Clypeorrhyncha.^[2]

Within the latter, the three traditional superfamilies – Cercopoidea (froghoppers and spittlebugs), Cicadoidea (cicadas) and Membracoidea – appear to be monophyletic. The leafhoppers are the most basal living lineage of Membracoidea, which otherwise include the families Aetalionidae (aetalionid treehoppers), Membracidae (typical treehoppers and thorn bugs), Melizoderidae and the strange Myerslopiidae.^[2]

Mating pair of Bothrogonia ferruginea, a Cicadellinae species known as tsumaguro-ōyokobai in Japan

Adult Eupteryx aurata of the Typhlocybinae

Subfamilies

Nymph of the Ledrinae Neotituria kongosana

The leafhoppers are divided into a high number (about 40) of subfamilies, which are listed here alphabetically as too little is known about the family's internal phylogeny. Some notable genera and species are also listed.

See also

• Planthopper
• Treehopper

References

References

• Lee et al. (2000): Phytoplasmas: phytopathogenic mollicutes. Annu. Rev. Microbiol. 54: 221-255. doi:10.1146/annurev.micro.54.1.221 (HTML abstract)
• Maddison, David R. (1995): Hemiptera. Version of 1995-JAN-01. Retrieved 2009-MAR-20.
• Tree of Life Web Project (TOL) (1995a): Auchenorrhyncha. Version of 1995-JAN-01. Retrieved 2009-MAR-20.
• Tree of Life Web Project (TOL) (1995b): Membracoidea. Version of 1995-JAN-01. Retrieved 2009-MAR-20.

Further reading

• Carver, M, FG. Gross, and TE. Woodward. 1991. Hemiptera (bugs, leafhoppers, cicadas, aphids, scale insects, etc.) In: The Insects of Australia - a Textbook for Students and Research Workers Volume 1. Melbourne University Press, Melbourne, Australia".

External links

Wikispecies has information related to: Cicadellidae

Wikimedia Commons has media related to: Cicadellidae

• Cicadellidae Taxonomy Site
• Red-banded leafhopper Graphocephala coccinea - diagnostic photographs and information
• Illinois Natural History Survey:leafhoppers
• West Virginia Leafhoppers
• Sharpshooter Leafhoppers of the World (Hemiptera: Cicadellinae) – Online Database with color photos of nearly all described species.
• Leafhoppers Pinellas County Florida
• Auchenorrhyncha keys, Australia and neighbouring areas