Anoplolepis gracilipes, known most commonly as the Yellow Crazy Ant (YCA), is a relatively large, yellow to orange colored ant with long legs, large eyes and extremely long antennal scapes. Considered by the IUCN/SSC Invasive Species Specialist Group (ISSG) to be among the 100 worst invasive species in the world, Anoplolepis gracilipes is widespread across the tropics, and populations are especially dense in the Pacific region. The species is most infamous for causing the "ecological meltdown" of Christmas Island (O'Dowd et al. 2003). Although widespread across the Pacific, Anoplolepis gracilipes can cause significant damage to native biological diversity, and strong quarantine measures are encouraged to keep it from spreading to new localities.