Contrasting Invasion Strategies, Convergent Outcomes: Establishment of Zaprionus tuberculatus and Ceroplastes ceriferus in Italy

Global warming and international trade are accelerating biological invasions, making the Mediterranean basin a hotspot for alien arthropods. Two invasive species, the drosophilid Zaprionus tuberculatus and the wax scale Ceroplastes ceriferus, were recently detected in central-southern Italy. Surveys conducted between 2023 and 2024 detected Z. tuberculatus across several sites in Campania and Lazio, and C. ceriferus in Campania. Zaprionus tuberculatus was reared from ten host plants, including three new records, and reached its highest abundance on persimmon. Laboratory assays showed that Z. tuberculatus adults reproduced only on intact fig fruits and blueberry, indicating a limited risk for most crops. Ceroplastes ceriferus was found on four hosts, confirming its polyphagy and establishment in southern Italy. Molecular analyses revealed two COI haplotypes in the Italian populations of both species, while three haplotypes were detected globally in Z. tuberculatus and seven in C. ceriferus. Sequence divergences were moderate, indicating limited but appreciable mitochondrial differentiation among geographic populations. In Z. tuberculatus, the COII haplotype detected in Italy did not match available African sequences, underscoring gaps in reference data and complicating the reconstruction of invasion routes. Despite contrasting ecological traits and dispersal strategies, both species achieved successful establishment in Italy, showing that ecological plasticity and human-mediated transport can offset reduced genetic diversity. These records expand the known European range of both species and highlight the need for coordinated surveillance, genetic monitoring, and preventive measures to limit further introductions in the Mediterranean region.