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Psyllid

Family of true bugs

  • 6 min read
  • 4 chapters

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Identification and biology

Psyllids are small and the largest are about half a centimetre long and can be mistaken and have a body shape that is similar to that of aphids in having a tubular abdomen tip, but lacking cornicles. They have a long 10-segmented antenna and three ocelli. Adults have strong hind legs adapted for leaping and both sexes are winged in adults. The wings are usually hyaline and show just a few veins. The radial, medial and cubital veins have one branch each. In some species the wings are patterned in black. In most species the wings are held over the body in tent-like position. In many species the apex of the wing is held raised at an angle. The proboscis is short and three segmented. The hind legs are modified and they have a large coxa, often with a backward facing process called a mercanthus. The structures on the hind legs are used in species identification. Psyllids are often collected for monitoring in yellow pan traps.

Psyllids hatch from eggs and go through five nymphal instars before they become adults. The winged adults are weak fliers but they can be dispersed widely by winds. They use their stylets to pierce plant tissue and feed on phloem sap. Feeding by nymphs causes leaf rolling, curling, rosette formation of growing buds, purpling, and chlorosis. They can also transmit bacteria, viruses, and phytoplasmas that affect plants. Diaphorina citri is noted for being a vector of citrus greening. Nymphs of a few psyllid species induce galls on plants and develop inside them either singly or in groups. The eggs have a stalk that is inserted into plant tissue and this induces gall formation in some species. Like other sternorrhyncha, they secrete wax and excrete honeydew with a few species attended by ants but some ant species are predators. One species Pachypsylla cohabitans is known to live as an inquiline inside the galls created by other psyllid species. Several genera of psyllids, especially among the Australian fauna, secrete coverings called "lerps" over their bodies, presumably to conceal them from predators and parasites. Psyllid parasitoids include Endopsylla (Diptera: Cecidomyiidae), which affects adults and numerous Hymenoptera that mostly lay their eggs on the nymphs.

Eogyropsylla paveloctogenarius described from 46 mya Eocene shales from Montana is considered the oldest member of the Psyllodea. Other Psylloidea fossils are described from Baltic amber of the Middle to Upper Eocene (44-38 mya). The explosive diversification of the flowering plants in the Cretaceous was paralleled by a massive diversification of associated insects, and many of the morphological and metabolic characters that the flowering plants exhibit may have evolved as defenses against herbivorous insects.

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Monotypic taxonTaxonomic group with only one subordinate taxonSpecies descriptionFormal description of a discovered speciesParaphylyType of taxonomic groupIUCN Red ListInventory of the global conservation status of biological speciesSubtropicsGeographic and climate zoneCommon nameName generally used for a taxon, group of taxa or organism(s)