Why do bees turn back and look?

Abstract

The timing of learning of colour and shape of the food source, as well as of near-by landmarks, was examined exploiting a behaviour described recently, the “Turn Back and Look” behaviour (TBL): Bees departing from a novel food source after feeding turn around to view it at a short distance (Figs. 2, 3) before departing for the hive. They repeat this behaviour on several successive visits, termed the “TBL phase” (Fig. 5). To examine the function of the TBL, I trained individual bees in 4 different modes. In the first 3 they could view a food source or a landmark of a particular colour or shape during (i) arrival as well as departure, (ii) only arrival, and (iii) only departure; in the final mode (iv) the bees viewed one colour (or shape) on arrival, and another on departure. At the end of the TBL phase, the bees were tested by offering them a choice between the visual stimulus to which they were trained (modes i–iii) and a different (novel) one, or between the stimulus viewed on arrival and that viewed on departure (mode iv). The test results show that learning after feeding (while performing the TBL), i.e. backward conditioning, occurs regardless of whether the colour (Fig. 6, Fig. 10a) or shape (Fig. 7) of the food source, or the colour (Fig. 10b), shape (Fig. 11), and position (Fig. 12) of a near-by landmark is considered. Bees trained in mode (iv) preferred the stimulus learned on arrival over that learned on departure in almost all cases. However, a stimulus viewed exclusively on departure (mode iii) was often learned as well as when it was viewed exclusively on arrival (mode ii) (Figs. 10a, 11, 12), or both on arrival and departure (mode i) (Fig. 6). The finding that the timing of learning can be manipulated suggests that it is not based on hard wired predispositions to learn particular visual cues on arrival, and others on departure.