| Leafhoppers | |
|---|---|
 | |
| Adult two-lined gumtreehoppers (Eurymeloides bicincta,Eurymelinae) with symbioticmeat ants | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Hemiptera |
| Suborder: | Auchenorrhyncha |
| Superfamily: | Membracoidea |
| Family: | Cicadellidae Latreille, 1802 |
| Subfamilies | |
24, see text | |
Leafhopper is the common name for anyspecies from thefamilyCicadellidae. These minuteinsects, colloquially known ashoppers, are plant feeders that suckplant sap from grass, shrubs, or trees. Their hind legs are modified for jumping, and are covered with hairs that facilitate the spreading of a secretion over their bodies that acts as a water repellent and carrier ofpheromones.[1] They undergo a partialmetamorphosis, and have various host associations, varying from very generalized to very specific. Some species have a cosmopolitan distribution, or occur throughout the temperate and tropical regions. Some are pests orvectors ofplant viruses andphytoplasmas.[1] The family is distributed all over the world, and constitutes the second-largest hemipteran family, with at least 20,000 described species.
They belong to a lineage traditionally treated asinfraorderCicadomorpha in thesuborderAuchenorrhyncha. This has sometimes been placed in its own suborder (Clypeorrhyncha),[2] but more recent research retains it within Auchenorrhyncha.[3]
Members of thetribeProconiini of thesubfamilyCicadellinae are commonly known assharpshooters.[4]
The Cicadellidae combine the following features:
An additional and unique character of leafhoppers is the production ofbrochosomes, which are thought to protect the animals, and particularly their eggclutches, from predation as well as pathogens.
Like otherExopterygota, the leafhoppers undergo direct development fromnymph to adult without apupal stage. While many leafhoppers are drab little insects as is typical for theMembracoidea, the adults and nymphs of somespecies are quite colorful. Some – in particularStegelytrinae – have largely translucent wings and resembleflies at a casual glance.
Leafhoppers havepiercing-sucking mouthparts, enabling them to feed onplant sap. A leafhoppers' diet commonly consists of sap from a wide and diverse range of plants, but some are morehost-specific. Leafhoppers mainly areherbivores, but some are known to eat smaller insects, such asaphids, on occasion. A few species are known to bemud-puddling, but as it seems, females rarely engage in such behavior. Many species are also known to opportunistically pierce the human skin and draw blood but the function of such behaviour is unclear.[5]
Leafhoppers aremicropredators that can act asvectors transmittingplant pathogens, such asviruses,phytoplasmas and bacteria.[6][7] Cicadellidae species that are significant agricultural pests include thebeet leafhopper (Circulifer tenellus), the maize leafhopper (Cicadulina mbila), potato leafhopper (Empoasca fabae), two-spotted leafhopper (Sophonia rufofascia),blue-green sharpshooter (Graphocephala atropunctata),glassy-winged sharpshooter (Homalodisca vitripennis), thecommon brown leafhopper (Orosius orientalis), rice green leafhoppers (Nephotettix spp.), and the white apple leafhopper (Typhlocyba pomaria). Thebeet leafhopper (Circulifer tenellus) can transmit the beet curly top virus to various members of thenightshade family, including tobacco, tomato, or eggplant, and is a serious vector of the disease inchili pepper in the Southwestern United States.
In some cases, the plant pathogens distributed by leafhoppers are alsopathogens of the insects themselves, and canreplicate within the leafhoppers'salivary glands. Leafhoppers are also susceptible to various insect pathogens, includingDicistroviridae viruses, bacteria andfungi; numerousparasitoids attack the eggs and the adults provide food for smallinsectivores.
Some species such as the AustralianKahaono montana even build silk nests under the leaves of trees they live in, to protect them from predators.[8]
In the now-obsolete classification that was used throughout much of the 20th century, the leafhoppers were part of the Homoptera, aparaphyletic assemblage uniting the basal lineages ofHemiptera and ranked assuborder. The splitting of the Homoptera is likely to be repeated for theAuchenorrhyncha for similar reasons, as the Auchenorrhyncha simply seem to group the moderately advanced Hemiptera, regardless of the fact the highlyapomorphicColeorrhyncha andHeteroptera (typical bugs) evolved from auchenorrhynchans. Hence, a recent trend treats the most advanced hemipterans as three or four lineages, namely Archaeorrhyncha (Fulgoromorpha if included in Auchenorrhyncha), Coleorrhyncha and Heteroptera (sometimes united asProsorrhyncha) and Clypeorrhyncha.[9][10][11]
Within the latter, the three traditionalsuperfamilies –Cercopoidea (froghoppers and spittlebugs),Cicadoidea (cicadas) andMembracoidea – appear to bemonophyletic. The leafhoppers are the mostbasal living lineage of Membracoidea, which otherwise include thefamiliesAetalionidae (aetalionidtreehoppers),Membracidae (typical treehoppers and thorn bugs),Melizoderidae, andMyerslopiidae.[9][10][11]
The leafhoppers are divided into 25subfamilies,[12] which are listed here alphabetically, as too little is known about the family's internalphylogeny.
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Data related toCicadellidae at Wikispecies
Media related toCicadellidae at Wikimedia Commons