Sea water transport and submersion tolerance as dispersal strategies for the invasive ground beetle Merizodus soledadinus (Carabidae)

• Published in: Polar Biology
• Main Author: Renault, David
• Other Authors: Ecosystèmes, biodiversité, évolution Rennes (ECOBIO), Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), programme 136 de l'IPEV, ANR-07-VULN-0004,EVINCE,Vulnerability of native communities to invasive insects and climate change in sub-antarctic islands.(2007)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2011
• Subjects: Biological invasion; Insect; Flotation; Survival; Kerguelen Islands; geo; envir; Antarctic; Kerguelen; Antarc*; Polar Biology
• Online Access: https://doi.org/10.1007/s00300-011-1020-3; https://hal.archives-ouvertes.fr/hal-00668344

International audience The alien ground beetle Merizodus soledadinus was introduced to the sub-Antarctic Kerguelen Islands in 1913. It colonized several small islands and islets of this archipelago, without any apparent human assistance in some locations, and crossed several large rivers and alluvial plains. As aggregations of this species on the tidal drift line are common at the Kerguelen Islands, the present work examined whether adult individuals of M. soledadinus could disperse by flotation on the sea. Different sample sizes of ground beetles (from 1 to 10) were placed on sea water at 8°C in plastic vials. Survival (50% lethal times) significantly increased from 2.1 ± 0.2 days for single beetles to 6.5 ± 0.3 days for groups of 10 beetles per vial, with there being no difference in the survival duration for groups of 2, 5, and 10 beetles per vial. Similar survival durations were found for beetles in vials with artificially agitated water and controls. In addition, the duration of survival was twice as high under freshwater versus sea water conditions, when groups of 10 adults were used. Finally, the survival to total submersion in freshwater was evaluated, and ranged from 3 to 4 days. This ability to survive extended periods both floating on and/or submerged beneath salt and freshwater conditions, indicates the presence of a successful dispersal mechanism, which may facilitate the dispersal range of M. soledadinus across the Kerguelen Islands, comprising over 300 islands and islets in total.