A study of the genus Thaumetopoea (Lepidoptera: Notodontidae), using morphological, ecological, andmolecular traits

Thaumetopoeinae include several species called processionary moths, mainly due to their gregarious behaviour to form long single lines to forage and to pupate. Even if historically it has been considered as a separate family, Thaumetopoeinae were recently included as a subfamily of Notodontidae, based on both cladistic and molecular analyses. This groups has a great importance for forestry and landscape because their larvae feed on trees and shrubs, both broadleaved and coniferous, defoliating the canopy and weakening the plants, making them more susceptible to tree killers (i.e. bark beetles). Furthermore, they threaten human and animal health due to the presence of urticating setae in larvae and/or adults that are used as an effective defence strategy against vertebrate predators. In humans, these setae are responsible of allergic reactions, also of strong intensity, from dermatitis to anaphylactic shock; instead in animals, they produce pruritus, necrosis, abortions, anorexia, up to death. Thaumetopoea is the most known genus and historically it has been split into three separated genera. A recent molecular study has defined the phylogenetic relationships and the evolution of life history traits for a few taxa of this genus that is mainly distributed in Europe, the Mediterranean and Iranoturanic areas. In the first study, I completed the phylogeny of the genus analysing all the 15 species of Thaumetopoea s. lat., introducing both rare species found in different museum collections, by defining a set of 165 traits from head, thorax, abdomen, wing and male genitalia. The very recently described Thaumetopoea loxostigma Hacker, 2016 could not be included as the only extant specimen, viz. the holotype, was not available. According to the original description, T. loxostigma is closely related to the Thaumetopoea apologetica – Thaumetopoea jordana group, which itself needs revision. Five subspecies other than nominal ones are currently recognised within Thaumetopoea , namely T. apologetica abyssinica, T. herculeana judaea, T. processionea pseudosolitaria, T. solitaria iranica, and T. pityocampa orana, and they were included in the analysis. Whenever possible, the specimens were compared with the types of the various species. Morphological traits were combined with 9 mitochondrial genes already present in literature for some species. For the others, I sequenced the barcoding portion of cox1 due to the difficulties to amplify old fragmented DNA also using ad hoc primers. Matrix was processed using different software, to test different approaches, and the analyses were conducted both on separated matrix (morphological vs. molecular) and in combined ones (morphological + molecular). Finally, morphological traits were plotted on reference tree in order to identify apomorphies and homoplasious changes useful to draw a morphological key for the Thaumetopoea genus. Furthermore, I selected ecological and life history traits: presence of urticating setae on larva; pupation site; larval seasonal feeding activity; host plant group; host plant family, in order to outline the traits of a possible ancestor of processionary moths. In the second study, I use the morphological traits collected and the large number of specimens analysed to draw a morphological key and distribution maps of the whole genus Thaumetopoea, which will be helpful to entomologists and foresters to identify the adult specimens both in museum collection and in field. In the meantime, I synonymised some taxa recently described, mainly for lack of diagnostic characters or inconsistency. In the third study, I focused on the single clade genus Thaumetopoea in order to collect the information about the species of the 'summer' Thaumetopoea from Eurasia, feeding on coniferous hosts. Information included morphological and life history traits. Furthermore, the work involved also T. cheela that is proposed to be included in this group based on morphology and indirect evidence of life history traits. Although some evidences supported the hypothesis that Cedrus could be the host on which most of speciation in the summer clade had happened, more studies have to be made, especially for the less known species. Although my works complete the phylogeny of the genus of Thaumetopoea and provide valid methods to identify the species, which is very important because of the group includes some of the most important forest pests that also affect human and domesticated animal health through the urticating setae, more work is left to do in order to complete the knowledge on some neglected taxa and to expand the analysis to other genera of the subfamily, which apparently share the same traits and are causing similar problems in other continents.