''Acraspis quercushirta'', the jewel oak gall wasp, is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

gall wasp Gall wasps, also incorrectly called gallflies, are hymenopterans of the family Cynipidae in the wasp superfamily Cynipoidea. Their common name comes from the galls they induce on plants for larval development. About 1,300 species of this generall ...

in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Cynipidae Gall wasps, also incorrectly called gallflies, are hymenopterans of the family Cynipidae in the wasp superfamily Cynipoidea. Their common name comes from the galls they induce on plants for larval development. About 1,300 species of this genera ...

tribe The term tribe is used in many different contexts to refer to a category of human social group. The predominant worldwide usage of the term in English language, English is in the discipline of anthropology. This definition is contested, in p ...

Cynipini (oak gall wasps), found in

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

. Hosts are

white oaks The genus ''Quercus'' contains about 500 species, some of which are listed here. The genus, as is the case with many large genera, is divided into subgenera and sections. Traditionally, the genus ''Quercus'' was divided into the two subgenera '' ...

, including bur oak, Gambel oak,

Chapman oak ''Quercus chapmanii'', commonly referred to as the Chapman oak, is a species of oak that grows in the southeastern United States. Description ''Quercus chapmanii'' is a shrub or small tree occasionally reaching a height of 6 meters (20 feet) but ...

swamp chestnut oak ''Quercus michauxii'', the swamp chestnut oak, is a species of oak in the white oak section ''Quercus'' section ''Quercus'' in the beech family. It is native to bottomlands and wetlands in the southeastern and midwestern United States, in coastal ...

, and chestnut oak.

Ecology and Life History

Like most oak gall wasps, this species has two generations per year - one asexual (or agamic) and one sexual, with each generation producing distinct

galls Galls (from the Latin , 'oak-apple') or ''cecidia'' (from the Greek , anything gushing out) are a kind of swelling growth on the external tissues of plants, fungi, or animals. Plant galls are abnormal outgrowths of plant tissues, similar to be ...

. The wingless females of the asexual generation emerge from their galls in fall and climb up an oak tree to oviposit in bud scales thereby inducing the gall development. These inconspicuous galls and their larval inhabitants overwinter and continue their development in spring before adults emerge in late May and early June. These sexual generation adults mate and the females oviposit on veins on the underside of host leaves. The induced gall is detachable, oval in shape, and the color can range from white to yellowish to tan or brown. The surface is fissured into facets that end in a short, hard point, reminiscent of

jewelry Jewellery ( UK) or jewelry (U.S.) consists of decorative items worn for personal adornment, such as brooches, rings, necklaces, earrings, pendants, bracelets, and cufflinks. Jewellery may be attached to the body or the clothes. From a western ...

. These galls typically fall with the leaves in autumn with the asexual female adults emerging shortly thereafter. Acraspis quercushirta gall on Quercus macrocarpa.jpg, gall, Jun 24 2022 Acraspis macrocarpae gall on Quercus macrocarpa.jpg, gall, Aug 30 2021

References

{{Taxonbar, from=Q49620782 Cynipidae Gall-inducing insects Oak galls Taxa named by Homer Franklin Bassett Insects described in 1864