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 Homoptera. They belong to a lineage traditionally treated as infraorderCicadomorpha 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 the second-largest hemipteran family. They have at least 20,000 described species. Thetribe Proconiini of the subfamily Cicadellinae is commonly known as sharpshooters.
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.
Like other Exopterygota, the leafhoppers undergo direct development from nymph to adult without apupal 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 asaphids 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), thecommon 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.
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