Making a trail: informed Argentine ants lead colony to the best food by U-turning coupled with enhanced pheromone laying

► Argentine ants exploiting different quality foods show different trail behaviour. ► U-turns were twice as likely when returning from high-quality than low-quality food. ► U-turners marked more often and made more marks than nonturners. ► Pheromone trails were built from food to nest, and faster from high-quality food. ► Instead of being mistakes or corrections, U-turns drive collective decision making.