Insects with nests need to forage and return to the nest. Nest location in the desert ant, Cataglyphis fortis, at a longer range relies primarily on visual cues and navigation by landmarks.* At closer range, these ants can locate their nest by either olfactory or visual cues. However, when presented only with a visual cue or only an olfactory cue, the ants learn the location more slowly. Presenting both olfactory and visual cues simultaneously results in rapid learning of the location often after only one successful nest location.
Ants that have been trained to both cues delivered simultaneously are later able to recognize the nest by either cue given singly. Ants store information about a location and use that information to navigate. The process ants use for nest location is robust to changes in environment surrounding that location. If either the odor or visual cues are altered, the ant is still able to identify its nest.
*Desert ants benefit from combining visual and olfactory landmarks. Kathrin Steck, Bill S. Hansson, Markus Knaden. Journal of Experimental Biology 2011 214: 1307-1312