Chalcid wasp

Chalcid wasps (/ˈkælsɪd/, from Greek khalkos, meaning "copper", for their metallic colour) are insects within the superfamily Chalcidoidea, part of the order Hymenoptera. It is one of the largest insect families, with some 22,000 known species, and an estimated total diversity of more than 500,000 species, meaning the vast majority have yet to be discovered and described.

Most of the species are parasitoids of other insects, attacking the egg or larval stage of their host, though many other life cycles are known. These hosts are to be found in at least 12 different insect orders including Lepidoptera (butterflies and moths), Diptera (true flies), Coleoptera (beetles), Hemiptera (true bugs), and other Hymenoptera, as well as two orders of Arachnida, and even one family of nematodes.

A few species are phytophagous and the larvae feed inside seeds, stems, and galls. Generally beneficial to humans as a group, chalcids keep various crop pests under control, and many species have been imported to control insect pests. Copidosoma floridanum serves as a useful example of a wasp that provides pest control, and most recently, the wasp's genome is being sequenced by the Human Genome Sequencing Center as part of the i5K project, which aims to sequence the genomes of 5,000 arthropods.