Speed–accuracy trade-off paradigm in cooperative transport of ants

Abstract

Cooperative transport, the coordinated movement of an object by multiple individuals, requiresconsensus, which can be time consuming. Speedy decisions, especially in competitive situations, maycome at the cost of reduced accuracy. To evaluate this speed—accuracy trade-off, we simulated interspecificcompetition scenarios during cooperative transport in ants by applying formic acid, a defensivealarm pheromone, to mimic attacks from 10, 100, 500 and 1000 ants. We used protein baits to stimulatecooperative transport in videorecorded trials performed in the field. We applied distilled water as acontrol for the no-competition condition. We measured the efficiency and accuracy of the cooperativetransport by measuring the time to initiate transport, counting the number of ants involved, estimatingthe transport speed, group sinuosity and directional bias. High-competition scenarios resulted in alower percentage of cooperative transport, shorter consensus time and more tortuous trajectoriescompared to low- or no-competition conditions. In these contexts, ants were more likely to abandon theresource entirely, indicating that competition can inhibit foraging. The transport speed and directionalbias were not affected by experimentally generated competition. Our results suggest that the trade-offbetween speed and accuracy is enhanced in competitive contexts, illustrating a novel way in whichcompetition can affect food acquisition in animal societies.