Genetic patterns, host use and larval morphology in Tunisian populations of Orgyia trigotephras

Orgyia trigotephras Boisduval 1829 (Erebidae Lymantriinae) is a polyphagous moth widely distributed across the Mediterranean Basin. Current taxonomy validates several taxa at subspecies level within this species. Two of them, Orgyia trigotephras anceps Oberthur 1884 and Orgyia trigotephras transiens Staudinger et Rebel 1901 were found to occur in Tunisia. Although considered a rare species in southern Europe, an extensive outbreak was observed in Tunisia in the last decade. In this paper we present details on genetic patterns (mitochondrial DNA marker CO1), on larval phenotypic traits and on host plant species of Tunisian populations of O. trigotephras. Tunisian specimens clearly differentiated into two lineages, restricted to western and eastern Tunisia respectively. Both Tunisian haplotype-lineages strongly diverge from southern Spanish and southern Italian "conspecifics", questioning current taxonomy. Furthermore, we describe four larval phenotypes occurring in Tunisia and register Quercus coccifera, Quercus suber, Erica multiflora and Pistacia lentiscus as the four main host plant species. There was no association of the two genetic lineages with larval phenotypic traits. However, host plant species differed significantly between the two lineages.