Final Activity Report Summary - POPFIME (Population dynamics of invasive forest seed insects) The project was concerned with the competition between invasive and naturalised species of seed insects in a Mediterranean forest ecosystem. The entomofauna exploiting seeds of true cedar, i.e. cedrus spp., constituted an interesting model of invading seed insects even though it had received little attention in the past. Cedar stands, mainly c. atlantica, were extensively planted since the 19th century on the northern side of the Mediterranean Sea, especially in southern France. An exhaustive inventory of cone and seed pests in French stands revealed the widespread presence of megastigmus pinsapinis, with pest having probably been introduced from North Africa, along along with c. atlantica seeds, at the time of introduction of this species for reforestation programs. M. pinsapinis was now widespread in the cedar stands of southern France where it could infest up to 80 of the observed seeds, and could be considered nowadays as being a naturalised species. A few specimens of another exotic seed insect, m. schimitscheki, were unexpectedly observed in 1995 in southern France in c. atlantica seeds. Earlier seed insect surveys indicated that m. schimitscheki was not present in southern France before 1994. The analysis of annual seed insect surveys showed the extension of m. schimitscheki from a putative point of introduction to surrounding cedar stands. The colonisation by m. schimitscheki was accompanied by a noticeable decrease of infestation by m. pinsapinis, potentially indicating that the former had a competitive advantage over the latter. Differences in emergence phenology and reproductive systems could explain this competitive advantage.
