The most notable advance in our knowledge of path integration in insects is
a new understanding of how the honeybee measures the distance that it trav
els during its foraging trips. Data from two groups show that the bee's odo
meter records distance in terms of the net amount of image motion over the
retina that is accumulated during a flight, Progress has also been made in
clarifying the relation between path integration and other navigational str
ategies. On unfamiliar ground, path integration is the only available means
of navigation. In familiar surroundings, however, guidance by landmarks ma
y override guidance by path integration. Path integration then becomes a ba
ck-up strategy that is used primarily when landmarks fail.