''Andricus infectorius'' is a species of gall-forming wasp. The species was named by the German biologist

Theodor Hartig Theodor Hartig (21 February 1805 – 26 March 1880) was a German forestry biologist and botanist. Biography Hartig was born in Dillenburg. He was educated in Humboldt University of Berlin, Berlin (1824–1827), and was successively lecturer and pr ...

, in 1843 and is found in Europe.

Description of the gall

The asexual generation is a 10–20 mm spherical gall, found from late-May through to October when it matures. Found on the terminal bud of a branch, it is initially green and as it matures darkens to dark brown; falling to the ground in the winter. The gall is found on Hungarian oak (''

Quercus frainetto ''Quercus frainetto'' (syn. ''Quercus conferta'' Kit., ''Quercus farnetto'' Ten.), commonly known as the Hungarian oak or Italian oak, is a species of oak, native to southeastern Europe (parts of Italy, the Balkans, parts of Hungary, Romania) and ...

''), sessile oak (''

Quercus petraea ''Quercus petraea'', commonly known as the sessile oak, Cornish oak, Irish Oak or durmast oak, is a species of oak tree native to most of Europe and into Anatolia and Iran. The sessile oak is the national tree of Ireland, and an unofficial emble ...

''), downy oak (''

Quercus pubescens ''Quercus pubescens'', the downy oak or pubescent oak, is a species of white oak (genus ''Quercus'' sect. ''Quercus'') native to southern Europe and southwest Asia, from northern Spain (Pyrenees) east to the Crimea and the Caucasus. It is also fou ...

'') and pedunculate oak (''

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 plant, native to most of Europe west of the Caucasus ...

''). Oak gall wasps often have two generations per cycle, with one sexual and one asexual; each creating different galls. According to Milan Zúbrik et al. (2013), the sexual generation of the gall is unknown, but likely to be on Turkey oak (''

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 bristles, ...

''). A very small, ovoid gall on the

catkin A catkin or ament is a slim, cylindrical flower cluster (a spike), with inconspicuous or no petals, usually wind-pollinated (anemophilous) but sometimes insect-pollinated (as in ''Salix''). They contain many, usually unisexual flowers, arranged cl ...

s of Turkey oak may be the sexual generation.

Distribution

This species has been found in some western and central European countries but is absent from Belgium, Germany, Spain and Switzerland. It has recently been found in Great Britain. A 2013 gall found on Trengwainton Carn, near

Penzance Penzance ( ; kw, Pennsans) is a town, civil parish and port in the Penwith district of Cornwall, United Kingdom. It is the most westerly major town in Cornwall and is about west-southwest of Plymouth and west-southwest of London. Situated ...

Cornwall Cornwall (; kw, Kernow ) is a historic county and ceremonial county in South West England. It is recognised as one of the Celtic nations, and is the homeland of the Cornish people. Cornwall is bordered to the north and west by the Atlantic ...

was initially identified as '' Andricus inflator''. According to Dr C Leach of the

British Plant Gall Society The British Plant Gall Society is a voluntary organisation which encourages cecidology, the study of plant galls, in the British Isles. It was formed in 1985. Its biannual journal, ''Cecidology'', is edited by Michael Chinery. Notable people ...

, it is more likely to be ''A. infectorius''.

References

{{Taxonbar, from=Q14592881 Cynipidae Gall-inducing insects Hymenoptera of Europe Insects described in 1843 Oak galls Taxa named by Theodor Hartig