Pleurota bicostella (Clerck, 1759)

Tabell, Jukka, Wikström, Bo, Mutanen, Marko, Bruckner, Harald & Sihvonen, Pasi, 2021, Subspecies of Pleurota bicostella (Clerck, 1759) revisited and descriptions of nine new species in the P. bicostella species group (Lepidoptera: Gelechioidea Oecophoridae: Pleurotinae), Zootaxa 4941 (4), pp. 451-486 : 452-453

Characterization of P. bicostella species group

Adults of the P. bicostella species group are characterized by grey forewings mixed with white scales and black dots. In most species, a white costal line and a brown subcostal line are also present. Subtriangular valvae are typical in the male genitalia, as well as funnel-shaped gnathos, long posterior lobes of juxta and ear- or crescent-shaped valval lobes. These features are the most important characters in discriminating among species. In the female genitalia, quadrate segment 8, moderately short apophyses anteriores (slightly longer than segment 8) and medially fused, broad, sclerotized branches of the apophyses anteriores, which form the convex, dorsal proximal margin of segment 8, are characteristic. Also, the shape of signa is a useful distinguishing feature.

The use of DNA barcoding proved helpful and supported species delimitation obtained from the morphological analysis. In the majority of species (n = 12), maximum intraspecific divergence is lower than 1 %. In two species it is 1.08 % and 1.24 %, respectively, and in one species 2.66 %. The mean intraspecific divergence is 0.63 %. Interspecific divergence to the nearest neighbour is much higher, the mean being 8.86 %, the minimum 2.79 % and the maximum 13.07 %.