The invasion of Tunisia by rhynchophorus ferrugineus (Coleoptera: Curculionidae): Crossing an ocean or crossing a sea?

Abstract

The red palm weevil, Rhynchophorus ferrugineus (Olivier) (Coleoptera: Curculionidae), is an invasive and injurious pest of palms that has extended its native range from Asia to Africa, the Middle East, and the Mediterranean Basin. In 2010, the morphologically indistinguishable Rhynchophorus vulneratus (Panzer) was detected and subsequently eradicated in California, USA. In 2011, a population of palm weevils was detected in ornamental palms in Tunis, Tunisia. Uncertainty over the identity of the weevil population in Tunisia led to conflicting speculation that the source populations emerged from infested palms illegally imported from either the USA or Italy. Mitochondrial haplotypes of specimens collected at multiple sites around Tunis were compared with haplotypes from global populations of R. ferrugineus and R. vulneratus, confirming that the Tunisian populations were R. ferrugineus. Moreover, the Tunisian populations had the same fixed mitochondrial haplotype ubiquitous in invasive populations throughout the Mediterranean Basin, and we conclude that the Tunisian populations most likely originated from imported infested palms from Europe, and not from palms imported from the USA.