01649nas a2200145   4500008004100000245007500041210006900116260000900185300001400194490000800208520115400216100001601370700001501386856010201401       2007                        eng d00aCollapse of an ant-scale mutualism in a rainforest on Christmas Island0 aCollapse of an antscale mutualism in a rainforest on Christmas I  cJuly  a1238-12460 v1163 a<p>Positive interactions play a widespread role in facilitating biological invasions. Here we use a landscape-scale ant exclusion experiment to show that widespread invasion of tropical rainforest by honeydew-producing scale insects on Christmas Island (Indian Ocean) has been facilitated by positive interactions with the invasive ant Anoplolepis gracilipes. Toxic bait was used to exclude A. gracilipes from large (9-35 ha) forest patches. Within 11 weeks, ant activity on the ground and on trunks had been reduced by 98-100%, while activity on control plots remained unchanged. The exclusion of ants caused a 100% decline in the density of scale insects in the canopies of three rainforest trees in 12 months (Inocarpus fagifer, Syzygium nervosum and Barringtonia racemosa), but on B. racemosa densities of scale insects also declined in control plots, resulting in no effect of ant exclusion on this species. This study demonstrates the role of positive interactions in facilitating biological invasions, and supports recent models calling for greater recognition of the role of positive interactions in structuring ecological communities.</p>
1 aAbbott, K L1 aGreen, P T  uhttps://antkey.myspecies.info/th/content/collapse-ant-scale-mutualism-rainforest-christmas-island