Geranium sanguineum, Polen, Stare Bialowieza © Sébastien Carbonnelle
openend gall with larva
to the best of our knowledge the pictures above represent the larvae of D. geranii: orange-red larvae that live solitarily, each in a swollen mericarp. This is in agreement with e.g. Mamaev & Krivosheina. But according to among others Skuhravá & Skuhravý (2012a) and Skuhravá, Skuhravý & Meyer the larvae may also live gregariously in the unopened swollen flower buds, that ultimately turn black and fall off. It is hard to believe that these descriptions refer to one and the same species; nevertheless already Kieffer, in the original description of the species, presents both alternatives. Probably univoltine; hibernation in the soil.
Béguinot (2012a), Buhr (1964b), Dauphin & Aniotsbehere (1997a), Gagné (2010a), Kieffer (1907a), Mamaev & Krivosheina (1993a), Redfern & Shirley (2011a), Roskam (2009a), Skuhravá & Skuhravý (1999a, 2003a, 2010a, 2012a), Skuhravá, Skuhravý & Buhr (2013a), Skuhravá, Skuhravý, Dauphin & Coutin (2005a), Skuhravá, Skuhravý & Meyer (2014a).