SPATIAL MEMORY AND SEARCHING EFFICIENCY

By combining elementary orientation mechanisms with a path-integration process, two spatial memory-based searching mechanisms were modelled. These mechanisms make it possible to account for the behaviour of many animals which locally increase their search effort in the vicinity of a given memorized location to discover with maximal efficiency a small target which is likely to be close to this location. Common examples are provided by desert arthropods searching for their burrow entrance or predators searching for clustered prey items. The spatial distributions of the search effort generated by the two spatial memory-based searching mechanisms were derived using computer simulations. The efficiency of a predator searching for clustered prey items with a mechanism of this type was computed in four habitat types with differing grains and/or heterogeneity levels. A predator exhibiting optimal spatial memory-based area-concentrated searching behaviour was able to harvest about 16 times more prey items (whatever the habitat type) than if it exhibited optimal area-concentrated searching behaviour without referring to a spatial memory, and almost three to five (depending on the habitat type) times more than if it did not exhibit any area-concentrated searching behaviour but moved in a straight line with an optimal constant speed. © 1994 The Association for the Study of Animal Behaviour.