Leafhopper - Description and Ecology

Description and Ecology

The Cicadellidae combine the following features:

• The thickened part of the antennae is very short and ends with a bristle (arista).
• Two ocelli (simple eyes) are present on the top or front of the head.
• The tarsi are made of three segments.
• The femora are at front with, at most, weak spines.
• The hind tibiae have one or more distinct keels, with a row of movable spines on each, sometimes on enlarged bases.
• The base of the middle legs is close together where they originate under the thorax.
• The 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 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 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), the Maize streak virus vector Cicadulina mbila, and the white apple leafhopper (Typhlocyba pomaria).

In some cases, the plant pathogens distributed by leafhoppers are also pathogens of the insects 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.