The life cycle of "Andricus hispanicus" (Hartig, 1856) n. stat., a sibling species of "A. kollari" (Hartig, 1843) (Hymenoptera: Cynipidae)

Abstract

The marble gallwasp, Andricus kollari, common and widespread in the Western Palaeartic, is known for the conspicuous globular galls caused by the asexual generations on the buds of several oak species. The sexual form known hitherto, formerly named Andricus circulans, makes small gregarious galls on the buds of Turkey oak, Quercus cerris; this oak, however, is absent from the Iberian Peninsula, where on the other hand the cork oak, Q. suber, is present. Recent genetic studies show the presence of two different populations or races with distribution patterns similar to those of Q. cerris and Q. suber. We present new biological and morphological evidence supporting the presence of a sibling species of A. kollari in the western part of its range (the Iberian Peninsula, southern France and North Africa), Andricus hispanicus n. stat.. Biological and morphological differences separating these two species from other closely related ones are given and the new sexual form is described for the first time. This form of A. hispanicus, causing isolated bud galls in Q. suber, is identical to Andricus mayeti n. syn. and Andricus niger n. syn. and so we consider A. mayeti and A. niger to be junior synonyms of A. hispanicus. Finally, possible causes of the speciation of A. kollari and A. hispanicus are discussed.