11.2. Recording whole flight path

Since a forager trained along a route to a feeder chooses the direction it would have taken if not being transported to an unexpected site, it was concluded that the bee applies an egocentric reference in navigation. The bee would be lost if it did not find back to the hive by steering towards a beacon at the hive or some other procedures of localizing the hive (Wehner and Menzel, 1990; Dyer, 1998; Collett et al., 2002). Since bees are not lost even if such beacons are not available and if they were not trained along a route (Menzel et al., 2000), it is necessary to follow their whole flight path after they have escaped from direct view and deduce from their initial flight path the spatial reference they may apply.

Harmonic radar provides the option to track bees over the range of several hundred meters (up to 3 km depending on the direction of flight relative to the radius of radar scan). The range of the radar scan depends strongly on the local conditions and can reach a radius of 1.5 km under ideal conditions. The working of the harmonic radar device has been described by several authors (Riley et al., 1996; Osborne et al., 1997; Riley and Smith, 2002).

11.2.4. Field studies