Biological invasions, national borders, and the current state of non-native insect species in Greece and the neighbouring Balkan countries

Invasive species are a major threat to biodiversity, likely a direct consequence of increasing globalization. Greece is situated on the crossroad between different continents, and has been invaded by several insect species in the past; nevertheless, a thorough investigation that would reveal and highlight the pathways and origins of insect species invasion has never been attempted. This study aims at filling this knowledge gap by providing a comprehensive review and in-depth analysis of the non-native entomofauna that has ever entered Greece. The role of neighbouring countries is likely significant, as is the unique features exhibited by each family, and these may help determine the progress of introduction (e.g. cryptic species, parthenogenetic reproduction, etc.). The flow of non-native species between Greece and its neighbouring countries over time shows some relationships with the historical course of turmoil in the region, highlighting for the first time a relation that has long been overlooked but nonetheless is of great economic importance.