Quercus robur, the pedunculate oak, is a species of flowering plant in the beech and oak family, Fagaceae. It is a large tree, native to most of Europe and western Asia, and is widely cultivated in other temperate regions. It grows on soils of near neutral acidity in the lowlands and is notable for its value to natural ecosystems, supporting a very wide diversity of herbivorous insects and other pests, predators and pathogens.
Galls or cecidia 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 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 some insect and mite plant galls. The study of plant galls is known as cecidology.
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 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 quercuscalicis is a gall wasp species inducing knopper galls.
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.
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.
The common spangle gall on the underside of leaves and the currant gall on the male catkins or occasionally the leaves, develop as chemically induced distortions on pedunculate oak, or sessile oak trees, caused by the cynipid wasp Neuroterus quercusbaccarum which has both agamic and bisexual generations.
Neuroterus numismalis is a gall wasp that forms chemically induced leaf galls on oak trees. It has both bisexual and agamic (parthenogenetic) generations and forms two distinct galls on oak leaves, the silk button gall and blister gall. The galls can be very numerous with more than a thousand per leaf.
Neuroterus anthracinus is a widely distributed gall wasp that forms chemically induced leaf galls on oak trees. N. anthracinus has both sexual and agamic generations and in consequence forms two distinct galls, the oyster gall and April-bud gall.
Andricus grossulariae is a gall wasp species inducing agamic acorn cup galls on oak tree acorn cups and sexual phase galls on catkins. Synonyms include Andricus fructuum, Andricus gemellus, Andricus intermedius, Andricus mayri and Cynips panteli.
Andricus dentimitratus is a gall forming wasp in the genus Andricus. The adults lay their eggs on various species of oak and the developing larvae causes the trees to create a large ornate gall. The oaks parasitised include Quercus frainetto, Q. petraea, Q. pyrenaica, Q. pubescens and Q. robur. The gall is formed out of the cup of the acorn. In cross-section it resembles a mushroom. It is woody, maroon, shiny and sticky. It grows up to 25 mm high and 20 mm wide. What resembles the head of the mushroom is lobed or toothed in various ways. The insect emerges from the narrowing, between the head and base.
Biorhiza pallida is a gall wasp species in the family Cynipidae. This species is a member of the tribe Cynipini: the oak gall wasp tribe. Cynipini is the tribe partially responsible for the formation of galls known as oak apples on oak trees. These are formed after the wasp lays eggs inside the leaf buds and the plant tissues swell as the larvae of the gall wasp develop inside. This wasp has a widespread distribution within Europe.
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.
Andricus aries is a species of gall-forming wasps, in the genus Andricus. The species was named by the French entomologist Joseph-Étienne Giraud, in 1859. It is commonly found in eastern Europe and during the 21st century has spread to western Europe.
Andricus curvator is a gall wasp which forms chemically induced leaf galls on oak trees and has both agamic and sexual generations. Agamic and sexual generations usually form two distinct galls on oak trees, but in the case of A. curvator there are six galls; the sexual generation usually on the leaf, occasionally in a twig or catkin, and the agamic generation in a bud. The wasp was first described by Theodor Hartig, a German biologist, in 1840 and is found in most of Europe.
Andricus corruptrix is a species of gall-forming wasp, in the genus Andricus. It is found in Europe.
Andricus inflator is a species of gall-forming wasps, in the genus Andricus, which has a sexual and an asexual generation, producing two different galls. The wasp was named by the German biologist Theodor Hartig, in 1840 and is found in Europe.
Andricus infectorius is a species of gall-forming wasp. The species was named by the German biologist Theodor Hartig, in 1843 and is found in Europe.
Andricus mukaigawae is a species of gall wasp native to southeastern Asia. It creates galls on the buds and leaves of oak trees. The galls are sometimes used by other gall wasps unable to create galls of their own, with both species sharing the gall.
