Pine processionary moths in Greece refined: introduction and population structure of Thaumetopoea pityocampa mtDNA ENA clade in Attica, Greece

Abstract

Pine processionary moths are widely recognized as major pests of conifers within the Mediterranean basin, and numerous studies have attempted to resolve questions regarding their distribution and population dynamics. Since 2009, it has been accepted that in addition to Thaumetopoea pityocampa and T. wilkinsoni, a third group exists in the region of East North Africa that is accordingly called the mtDNA ENA clade. Exhaustive sampling within the Attica Region (Greece) revealed that individuals of the ENA clade have somehow infiltrated the area, contrasting the commonly accepted idea that continental Greece is inhabited solely by T. pityocampa. The occurrence of only a single population in Attica containing T. pityocampa haplotypes in concert with conclusions derived from population structure indices argues for a recent introduction followed by an on-going expansion. To that, the high similarity between Greek and Libyan haplotypes suggests a likely source population of the introduced individuals. This outcome not only complements previous studies on the expansion of pine processionary moths, but also provides valuable information that needs to be considered when planning a management strategy.