''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.

Description

Adults lay their eggs on various species of oak, including ''

Quercus robur ''Quercus robur'', commonly known as common oak, pedunculate oak, European oak or English oak, is a species of flowering plant in the beech and oak family, Fagaceae. It is a large tree, native to most of Europe west of the Caucasus. It is widel ...

'', '' Q. petraea'', '' Q. pubescens'' and '' Q. cerris'', The developing larvae cause the trees to create an elongated gall, reminiscent of a ram's horn, hence the epithet ''

aries Aries may refer to: *Aries (astrology), an astrological sign *Aries (constellation), a constellation of stars in the zodiac Arts, entertainment and media * ''Aries'' (album), by Luis Miguel, 1993 * ''Aries'' (EP), by Alice Chater, 2020 * "Aries" ...

'' and the vernacular name "ram's horn gall wasp". Green at first, the gall can be reduced to a single strap or can just be 5 mm long. It later hardens, turns brown and is especially variable when the gall contains

inquiline In zoology, an inquiline (from Latin ''inquilinus'', "lodger" or "tenant") is an animal that lives commensally in the nest, burrow, or dwelling place of an animal of another species. For example, some organisms such as insects may live in the h ...

s ('' Synergus'' species). ''A. aries'' does not cause galls to form on acorns but causes galls to develop on leaf buds on twigs, these have a variety of forms which are due to the activities of

parasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...

s and

s. Its sexual stage is found on the catkins of Evergreen Oak In northwestern Europe, at least, their reproduction is solely asexual generation, however, experiments have demonstrated that newly emerged females will lay eggs in the axillary buds of ''

Quercus cerris ''Quercus cerris'', the Turkey oak or Austrian oak, is an oak native to south-eastern Europe and Asia Minor. It is the type species of ''Quercus'' sect. ''Cerris'', a section of the genus characterised by shoot buds surrounded by soft bristle ...

''. ''A. aries'' has been found, like other species of gall wasp which have colonised the British Isles, to have been utilised by native parasitoids since their arrival, and that their parasitoids from continental Europe have not followed them across the

English Channel The English Channel, "The Sleeve"; nrf, la Maunche, "The Sleeve" (Cotentinais) or ( Jèrriais), (Guernésiais), "The Channel"; br, Mor Breizh, "Sea of Brittany"; cy, Môr Udd, "Lord's Sea"; kw, Mor Bretannek, "British Sea"; nl, Het Kana ...

Distribution

It is found primarily in eastern Europe, but in the 21st century has spread to western Europe including the United Kingdom. If was first recorded in Maidenhead Thicket, Berkshire in 1997 and since then has spread all over the southern half of England.

References

External links

Plant Parasites of Europe
Andricus aries - Sot's Hole - 2014-09-03 - Andy Mabbett - 04

{{Taxonbar, from=Q14678420 Cynipidae Gall-inducing insects Hymenoptera of Europe Insects described in 1859 Oak galls Taxa named by Joseph-Étienne Giraud