Route learning and transport of resources during colony relocation in Australian desert ants.

Abstract

Many ant species can respond to dramatic changes in local conditions by relocating the entire colony to a new location. While we know that careful learning walks enable the homing behavior of foraging ants to their original nest, we do not know whether additional learning is required to navigate to the new nest location. To answer this question, we investigated the nest relocation behavior of a colony of Australian desert ants (Melophorus bagoti) that relocated their nest in response to heavy rainfall in the semidesert terrain of Alice Springs. We identified five types of behavior: exploration between nests (Old-to-New nest and New-to-Old nest), transport from Old to New nest, and relearning walks at Old and New nests. Initially, the workers performed relearning walks at the Old nest and exploratory walks between the Old and New nests. Once they completed the exploratory walks, the workers transported resources and brood to the new nest. Finally, we observed the workers performing relearning walks at the New nest. While the relearning walks at the Old nest were slow and appear to enable exploratory walks to the New nest, the relearning walks at the new nest were faster and appeared to enable homing from foraging trips. These observations shed insight on how learning helps these ants to respond to sudden changes in their environment.