Experience improves navigational knowledge of dumpers in desert ants ( Melophorus bagoti )

ABSTRACT The Australian red honey ant, Melophorus bagoti , is an excellent desert navigator, performing all the activities outside the nest during the hottest periods of summer days. This species relies heavily on path integration and landmark cues for outbound and inbound navigation. Although the species navigational behaviours have been much studied, the spatial knowledge of workers that dump waste has not been investigated. In our study, we investigated the navigational knowledge of both naive and experienced dumpers by displacing them 2 metres away from the nest. Naive dumpers were not oriented towards the nest in their initial trajectory at any of the test locations, whereas experienced dumpers were significantly oriented towards the nest at all test locations. Naive dumpers were nest-oriented as a group, however, at the test location nearest to where they dumped their waste. Compared with experienced dumpers, the paths of naive dumpers were more sinuous, and naive dumpers scanned more on tests. Overall, our findings suggest that dumpers gain greater spatial knowledge through repeated dumping runs outside the nest, contributing to successful homing behaviour.