Gall wasps

Definition

A group of small wasps in the superfamily Cynipoidea, family Cynipidae, whose larvae develop inside plant galls—abnormal growths that the wasps chemically and mechanically induce on host plants. The gall provides nutrition and protection; many species show complex alternation of generations with different gall forms on different host plants or plant parts. Most gall wasps are associated with oaks (Quercus) and related Fagaceae, though some attack roses, willows, and other plants. The family comprises roughly 1,300 described species worldwide.

Etymology

From the galls (abnormal plant swellings) that their larvae inhabit; 'cynipid' derives from Greek kynips, a name for a small insect.

Example

The California gall wasp Andricus quercuscalifornicus induces large, woody galls on valley oak (Quercus lobata) twigs; the alternate generation produces small, detachable galls on oak leaves.

Synonyms

• cynipids
• gallflies

Related Terms

• gall
• Cynipidae
• Cynipoidea
• Alternation of generations
• inquiline
• host plant
• induced plant response

Usage Notes

Formerly, families Paraulacidae and Diplolepididae were treated as subgroups within Cynipidae but are now recognized as separate families based on molecular phylogenetics. 'Gallfly' is an older common name and can cause confusion with true flies (Diptera) that also form galls. The term 'gall wasp' properly refers only to Cynipidae and close relatives in Cynipoidea, not to other gall-inducing Hymenoptera such as some Chalcidoidea or Tenthredinidae.