First report of <em>Colias croceus</em> ab. <em>cremonae</em> in Italy

Abstract

We report on the first observation for Italy of ab. cremonae Verity, 1911 of Colias croceus (Fourcroy, 1785). This is an extremely rare form characterized by a lemon-yellow background color instead of the orange color typical of the nominal form of Colias croceus. This peculiarity is linked to a genetic mutation that suppresses the expression of orange/red (and pink) coloration due to erythropterin pigments, so that their absence prevents the appearance of orange color on the wings and of the pink color normally observed on the antennae, legs, fringes, and the hair vestiture of the head and thorax. The present report is based on a single male specimen recorded on 7 October 2021 near Benna (Biella, Piedmont), where Colias croceus was abundant. The presence of this aberration is relatively frequent in the Azores Islands (particularly Faial) and has also been reported for Madeira and Hasmieh (Lebanon), the site of origin of the first specimen ever collected. This aberration was previously unrecorded in Italy and is yet unknown in most of continental Europe. Another yellow aberration of Colias croceus, known as ab. erateformis, originally recorded in Romania and, later, from other West Palaearctic (mostly Mediterranean) areas, is considered a different one in which the red pigment is still present.