Probing the genesis of habitual routes.
A significant practical benefit of studying navigation in ants, is that one can record in detail the foraging history of an individual ant in natural environments where one can also record ant’s eye views of the world. However, this isn’t often done, so it is really good to see this paper by Mangan and Webb investigating route development in Cataglyphis velox. In a naturalistic foraging situation the development of routes was observed in marked individuals, prior to probe displacement tests. Notable observations that are suggestive of route mechanisms, include:
** A beautiful Figure 2 which shows that individuals can hold multiple stable routes between the same start and end points. This suggests that routes are built from reactions to current locations rather than a rigid sequence of actions.
** A replication of the Kohler and Wehner result where displacements (from feeeder or nest) to points along routes do not lead to any deficit in route recapitulation. Showing the independence of route folowing and Path Integration.
** Ants released lateral to their idiosyncratic route would only “recognise” their route if their search path crossed the route at an acute angle. Suggestive of view-point dependent recognition of on route locations.
** Chance discovery of natural food items on the way the well-known feeder, leads to the rapid learning of new routes. Demonstrating how route learning is fast and ‘always on’.
These are all lovely behavioural observations, however the authors also collected ant’s perspective images from the experimental area. Therefore the behavioural data will provide added value through a follow-up analysis of the potential visual mechanisms that might explain route performance in ants.
Michael Mangan and Barbara Webb (2012) Spontaneous formation of multiple routes in individual desert ants (Cataglyphis velox) Behavioral Ecology. doi:10.1093/beheco/ars051