2018 Completion Abstracts

2018 Completion Abstracts

Cody Freas

Talk Title: Learning, Memory and Cue Choice in Navigating Ants
Abstract: A critical reoccurring challenge facing mobile animals is the need to reliably find goal locations (e.g. food or the nest). To solve this problem, animal navigators acquire and use multiple cue sets within their environment, which designate direction and distance estimates of these locations. Navigational cues can conflict, which adds a further challenge, requiring the navigator to integrate these cues before moving. Foraging ants are expert visual navigators known to use both learned panorama cues and path integration to navigate. Here we examine the navigational memory, learning and cue choice in the Australian desert ant species, Melophorus bagoti. M. bagoti is a solitary foraging desert ant endemic to Central Australia. In Experiment 1, we show that foragers retain robust memories of both the nest skyline and multiple non-nest site skylines. Forager orientation performance shows evidence of retroactive interference after changes are made to the skyline at the same site. In Experiment 2, when M. bagoti foragers are presented with cue conflicts between the terrestrial and celestial cue sets, foragers appear to choose dynamically based on experience and cue reliability in accordance with the Temporal Weighting Rule. In Experiment 3 we tested foragers with directional conflicts in their inbound and outbound routes. Foragers repeatedly presented this conflict show evidence of rapid vector calibration to the inbound route. This calibration appears to have a directional limit of around 45˚. Finally, in Experiment 4 we tested foragers ability to learn panorama cues away from the nest. When foragers are restricted to the nest site, they appear unable to extrapolate panorama cues from the nest to local sites. Yet, these foragers only require one experience of the homeward route to learn the correct nest direction. Furthermore, exposure to the outbound foraging path appears critical for efficient homeward route formation in this species.

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