Galls or cecidia are a kind of swelling growth on the external tissues of plants. Plant galls are abnormal outgrowths of plant tissues, similar to benign tumors or warts in animals. They can be caused by various parasites, from viruses, fungi and bacteria, to other plants, insects and mites. Plant galls are often highly organized structures so that the cause of the gall can often be determined without the actual agent being identified. This applies particularly to insect and mite plant galls. The study of plant galls is known as cecidology.
Gall wasps, also traditionally calledgallflies, 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 generally very small creature are known worldwide, with about 360 species of 36 different genera in Europe and some 800 species in North America.
Oak apple or oak gall is the common name for a large, round, vaguely apple-like gall commonly found on many species of oak. Oak apples range in size from 2 to 4 centimetres in diameter and are caused by chemicals injected by the larva of certain kinds of gall wasp in the family Cynipidae.
Andricus kollari, also known as the marble gall wasp, is a parthenogenetic species of wasp which causes the formation of marble galls on oak trees. Synonyms for the species include Cynips kollari, Andricus quercusgemmae, A. minor, A. indigenus and A. circulans.
Andricus foecundatrix is a parthenogenetic gall wasp which lays a single egg within a leaf bud, using its ovipositor, to produce a gall known as an oak artichoke gall, oak hop gall, larch-cone gall or hop strobile The gall develops as a chemically induced distortion of leaf axillary or terminal buds on pedunculate oak or sessile oak trees. The larva lives inside a smaller hard casing inside the artichoke and this is released in autumn. The asexual wasp emerges in spring and lays her eggs in the oak catkins. These develop into small oval galls which produce the sexual generation of wasps. A yew artichoke gall caused by the fly Taxomyia taxi also exists, but is unrelated to the oak-borne species. Previous names or synonyms for the species A. fecundator are A. fecundatrix, A. pilosus, A. foecundatrix, A. gemmarum, A. gemmae, A. gemmaequercus, A. gemmaecinaraeformis and A. quercusgemmae.
Cola-nut galls develop as a chemically induced distortion of leaf axillary or terminal buds on pedunculate oak or sessile oak trees, caused by the agamic gall wasp Andricus lignicola which lays single eggs within leaf buds using their ovipositor. A previous name or synonym for the species A. lignicola is A. lignicolus and A. venheurni.
Andricus is a genus of oak gall wasps in the family Cynipidae.
Andricus quercuscalifornicus, or the California gall wasp, is a small wasp species that induces oak apple galls on white oaks, primarily the valley oak but also other species such as Quercus berberidifolia. The California gall wasp is considered an ecosystem engineer, capable of manipulating the growth of galls for their own development. It is found from Washington, Oregon, and California to northern regions of Mexico. Often multiple wasps in different life stages occupy the same gall. The induced galls help establish complex insect communities, promoting the diversification in niche differentiation. Furthermore, the adaptive value of these galls could be attributed their ecological benefits such as nutrition, provision of microenvironment, and enemy avoidance.
Feron kingi, the red cone gall wasp, is a species of gall wasp in the family Cynipidae.
Feron crystallinum, also known as the crystalline gall wasp, is a species of gall-forming wasp in the genus Feron. Its galls are pink and covered in hairs that are white, red, or brown. These galls are often massed together in clumps that can cover the underside of leaves. Individual galls are 12–14 mm high, 7 mm across, and have a single chamber for larvae. The unisexual female generation emerges in late winter, and the bisexual generation of males and females emerges in March. They are found in all species of oaks in California.
Feron parmula, also known as the disc gall wasp, is a species of oak gall wasp in the genus Feron. It induces galls in a wide selection of oak species, especially white oaks, and including hybrids. The galls are disc-shaped, up to 3 mm in diameter, and pale with red streaking. Adult females emerge in April. The galls induced by F. parmula superficially resemble the galls of Feron gigas,Andricus viscidus, and newly identified species called the "plate gall wasp" and the "orange-cap gall wasp" by Ronald Russo. Galls induced by this wasp have been documented in Oregon and California on the Pacific coast of North America.
Feron gigas, also known as the saucer gall wasp, is a species of gall-forming wasp in the genus Feron. It induces galls on the leaves of scrub oaks, blue oaks, and Engelmann oaks. The galls produced by its all-female generation, which emerges in winter, are 3-4 mm wide, circular with raised edges. They are red, pink, brown, or purple. The larval chamber exists as a raised bump in the gall's center. The bisexual generation produces galls that are brown and cone-shaped.
Feron bakkeri, also known as the pinched leaf gall wasp, is a relatively uncommon species of gall-inducing hymenopteran. They produce pink leaf galls on Oregon oaks and scrub oaks. The distribution of this wasp is California and Oregon in North America. It was previously placed in the genus Andricus.
Callirhytis serricornis, formerly Andricus serricornis, the kernel flower gall wasp, is a species of hymenopteran that produces galls on oak trees in California in North America. The wasp oviposits on coast live oak and interior live oak and induces a gall shaped roughly like a bottle or vase. The gall is brown in the first generation, and red and green in the second.
Trichoteras is a genus of gall-inducing Hymenopteran that has several species formerly classed as Andricus. Trichoteras characteristics include antennae with 10 flagellomeres. An entomologist writing in 2018 stated that "is questionable that Heteroecus and Trichoteras should be synonymized with Andricus" in regard to a proposed taxonomic reorganization of 2002. Ronald A. Russo in Plant Galls of the Western United States moves species like the golden oak apple wasp from Andricus to Trichoteras, while acknowledging the previously accepted binomials. William Harris Ashmead first defined this genus in 1897.
Trichoteras coquilletti, formerly Andricus coquilletti, also known as the little oak-apple gall wasp, is a fairly common species of cynipid wasp that produces galls on oak trees in North America. This wasp oviposits on the underside of the leaves of huckleberry oaks and canyon live oaks. The larval chamber is at the center of the gall, connected to the husk by slender, radiating fibers.
Callirhytis congregata, formerly Andricus congregata, the sausage flower gall wasp, is a species of hymenopteran that induces galls on the catkins of coast live oaks, interior live oaks, and canyon live oaks in California in North America. This wasp is considered locally common. William Harris Ashmead described Andricus congregatus as producing a gall like a "rugose, yellowish brown woody swelling, containing numerous cells growing apparently from the extreme tips of very slender twigs of Quercus chrysolepis, the gall appearing to have a long peduncle".
Atrusca brevipennata, formerly Andricus pellucidus, also known as the little oak-apple gall wasp, is a locally common species of cynipid wasp that produces galls on oak trees in North America. The wasp oviposits on shrub live oak and Gambel oak leaves. The larval chamber is at the center of the gall, connected to the husk by slender, radiating fibers. This wasp is most commonly observed in the American Southwest, as far north as Denver. It is visually similar to, and may be confused with, Atrusca bella.
Besbicus maculosus, formerly Andricus maculosus and Cynips maculosa, also known as the pear gall wasp, is an uncommon species of cynipid wasp that induces galls on oak trees on the west coast of North America. The wasp oviposits on leather oak and scrub oak leaves. Fresh galls are green. This wasp has been observed in California.
Andricus chrysolepidicola , also known as the irregular-spindle gall wasp, is a species of cynipid wasp that induces stem galls on blue oaks, valley oaks, scrub oaks, and leather oaks in North America. The stem galls are the first-year unisexual gall of this species; a second-year bisexual generation induces bud galls. This species is primarily known from California but may found elsewhere along the Pacific coast and inland to Nevada.
