Andricus aries

Andricus aries is a species of gall-forming wasps, in the genus Andricus.[1][2] The species was named by the French entomologist Joseph-Étienne Giraud, in 1859.[3][4] It is commonly found in eastern Europe and during the 21st century has spread to western Europe.

Andricus aries
A. aries gall photographed in England in September.
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Cynipidae
Genus:	Andricus
Species:	A. aries
Binomial name
Andricus aries Giraud, 1859

Description

Adults lay their eggs on various species of oak, including Quercus robur, 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 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 inquilines (Synergus species).[5][6] A. aries is 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 parasites and inquilines.[7] 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.[8] 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.[9]

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.[10]

References

1. "Hymenoptera Galls". British Plant Gall Society. Archived from the original on 4 September 2014. Retrieved 4 September 2014.
2. "Ram's-horn Gall Wasp - Andricus aries". Nature Spot. Retrieved 21 November 2019.
3. Giraud, J. E. (1859). "Signalements de quelques espèces nouvelles de Cynipides et de leurs Galles". Verhandlungen des Zoologisch-Botanischen Vereins in Wien. 9: 337–374.
4. "Andricus aries (Giraud, 1859)". Natural History Museum. Retrieved 4 September 2014.
5. Bijkerk, J. (2004). "Andricus aries, the Ramshorn gall, now discovered in the Netherlands". Cecidology. 19 (1): 19–20. ISSN 0268-2907.
6. Redfern, Margaret; Shirley, Peter; Boxham, Michael (2011). British Plant Galls (Second ed.). Shrewsbury: Field Study Council. pp. 231–260. ISBN 978-185153-284-1.
7. Tony Simpson & Brett Westwood (November 2013). "Ramshorn Gall Andricus aries found in Worcestershire". Worcestershire Record. Worcestershire Biological Records Centre & Worcestershire Recorders. 35: 45. Retrieved 14 March 2020.
8. "Andricus aries (Giraud, 1859) ramshorn gall wasp". Plant Parasites of Europe leafminers, galls and fungi. W.N. Ellis. Retrieved 14 March 2020.
9. Karsten Schönrogge; Tracey Begg; Robin Williams; George Melika; Zoë Randle (2011). "Range expansion and enemy recruitment by eight alien gall wasp species in Britain". Insect Conservation and Diversity. 5 (4): 298–311. doi:10.1111/j.1752-4598.2011.00161.x.
10. Chinery, Michael (2011). Britain's Plant Galls. Old Basing, Hampshire: WildGuides Ltd. p. 14. ISBN 978 190365743 0.

External links

• Plant Parasites of Europe

A. aries gall photographed in England in September.