Chaos and fighting ensue when predatory raider ants (black) enter a nest of their Stigmacros prey. Harrietville, Victoria, Australia
Fighting ensues when both Acromyrmex disciger leafcutting ants and Pheidole vafra big-headed ants arrive at a cookie bait. Although the Pheidole won this particular fight, the larger battle went to the leafcutters, and within 20 minutes of taking this photo the Pheidole had vanished. Morretes, Paraná, Brazil
Linepithema iniquum from different nests, fighting. Myrmecologists can sometimes measure the territory of an an colony by testing the aggression of ants collected at different distances. Morretes, Paraná, Brazil