How can large flightless beetles disperse by flight? The role of the omnivorous gulls on an oceanic island

Trabajo presentado en el el congreso Island Biology 2014 celebrado en Hawai del 7 al 11 de julio de 2014.The enigma of how large insects can colonize oceanic islands has not being satisfactory explained and often has been attributed to stochastic processes linked to oceanic rafts or other undocumented means of dispersals. Once on an island, these insects often undergo processes of evolutionary radiation, as in the case of the 13 taxa of Pimelia (Coleoptera: Tenebrionidae) within the Canary archipelago. Field observations carried out in 1986 (El Hierro island), revealed that omnivorous gulls (Larus michahellis) can regurgitate large intact Pimelia laevigata (≈ 16 gr), some of which survived digestion by this large bird. In response to this observation we developed a research project funded by the Canary Island Government (2010-2013). We recorded this process in at least 15 times in the field, and also under experimental conditions. Furthermore, the frequent and high consumption of Pimelia by seagulls takes place during spring and the beginning of summer, coinciding with the optimum 132 maturation of the female eggs. Therefore, post-regurgitation colonization success of this beetle is presumablyfavorable. A parallel study on mitochondrial DNA has been developed, whose preliminary data indicate a lack of population genetic structure within Pimelia of El Hierro, which, at least in part, could be attributable to this singular phenomenon. Although at the moment we are unable to extrapolate biogeographical implications of this particular process in a context of oceanic islands, this is the first time that is documented how a bird can successfully disperse an invertebrate.Peer Reviewe