The beetles can be found from May to July, with the female makes a horseshoe shaped cut and laying an egg in the incision.[3] The gall develops in an internode as a symmetrical swelling, which can be 20 mm long, and contains a yellowish larva or pupa in a single elongate chamber. An exit hole is made in the spring.[4] It is most common on aspen (Populus tremula) and also found on black cottonwood (P. trichocarpa), black poplar (P. nigra) and goat willow (Salix caprea).[5]
In Britain the gall is commonest on the young twigs of aspen.[4]
Distribution
Has been recorded in the following countries, Albania, Algeria, Austria, Belarus, Belgium, Bosnia and Herzegovina, Bulgaria, Canada, China, Croatia, Czech Republic (Bohemia, Moravia), France, Germany, Hungary, Italy, Japan, Kazakhstan, Luxembourg, Mongolia, Morocco, Mexico, North Korea, Poland, Romania, Russia, Sardinia, Serbia, Sicily, Slovakia, Slovenia, Spain, Sweden, Norway, Switzerland, Turkey, United Kingdom, United States of America.[2]
