|any small solitary wasp of the family Cynipidae and related families that produces galls in plant tissue, which provide shelter and food for the larvae|
any of a group of wasps in the family Cynipidae (order Hymenoptera) that are notable for their ability to stimulate the growth of galls (tissue swellings) on plants. Some gall wasp species are gall inquilines, meaning they do not cause the formation of galls but inhabit those made by other insects. The overgrowth of tissue, or gall, presumably is caused by a substance secreted by the immature insect living within it.
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