Spatial dynamics of supercolonies of the invasive yellow crazy ant, Anoplolepis gracilipes, on Christmas Island, Indian Ocean

*[This study examines the spatial dynamics of high-density supercolonies of the invasive yellow crazy ant, Anoplolepis gracilipes, on Christmas Island, Indian Ocean, and the associated impacts at their boundaries. Since the early 1990's, A. gracilipes supercolonies have occupied over 30% of the 10,000-ha of rainforest on Christmas Island. Thirty-four discrete high-density supercolonies formed between 1989 & 2003, ranging in size across nearly 3-orders of magnitude from 0.9 to 787-ha. Supercolonies boundaries are diffuse, & ants were observed in low densities in some cases up to 200-m from the main high-density supercolony. The 13 boundaries examined were all dynamic over a 10-20 observation month period, 9 boundaries expanded, & the maximum rate of spread was 0.5-m day-1. Across boundary transition zones, between high-density supercolonies & intact rainforest, A. gracilipes reduced other ant species richness, occupied red crab burrows, & killed resident red crabs, which was the trigger for 'invasional meltdown' on Christmas Island. The highly variable & unpredictable nature of A. gracilipes boundaries poses a challenge for incorporation into a predictive framework, as well as for their management. Gives good evidence that mating flights do occur as well as colony budding.]