Invasive fruit, cone and seed insects in the mediterranean basin

Abstract

Invasive fruit, cone and seed insects are considered the most important predators of tree seeds during the pre-dispersal phase of development. Although some species benefited from historical human movements across the Mediterranean Basin, the accelerating rate of international trade, travel and transport of wood products, including seeds, during the latter half of the twentieth century has increased the introduction of alien fruit, cone and seed insects in this area. The combination of almost inexistent phytosanitary regulations of tree seed trades and species biological characteristics favouring human-aided dispersal had a key role in successful invasions of Mediterranean forest ecosystems. Invasions may affect plant populations through increased direct trophic interactions such as seed parasitism and destruction, which can result in more complex indirect effects on natural regeneration processes. Many of the trees cone and seed insects feed upon have also been introduced by humans, but introduced insect species also may switch to native tree species congeneric to their original host and are then likely to interact with native seed feeders. In this chapter, we gathered current knowledge on seven insect species with invasive populations in the Mediterranean Basin. We put an emphasis on: (i) both anthropogenic and biological features involved in such invasion pathways, (ii) the ecological mechanisms involved in the establishment and the spread of invasive populations, (iii) the impacts of alien invasive species on Mediterranean ecosystems, and (iv) the issues related to the management of invasions in the fruit, cone and seed insect group.