Dashed line represents the average p of the mean waggle durations recorded in conditions (a,b), and the lower dashed line indicates (1/ 2) times this value. (Online version in colour.)the durations of waggle dances of bees that had returned from a 12 m long tunnel illuminated with polarized light that was oriented either ARQ-092 side effects axially (figure 8a), or transversely (figure 8b), or transversely for the first 6 m and axially for the final 6 m (figure 8c). The mean waggle duration recorded with axial polarization (216.4 + 1.9 (s.e.) ms; 11 bees, 11 dances, 100 waggles) is not significantly different from that recorded with transverse polarization (234.4 + 8.3 (s.e.) ms; 17 bees, 17 dances, 102 waggles) (t-test, p ?0.07). The average of these two durations is 227.3 + 6.4 ms. The waggle durations recorded in each of these conditions are very similar to those recorded for flights under the open sky in Experiment 1. Those durations, recorded on 13 March 2008, are: 191.9 + 20 (s.e.) ms (9.15 ?.30), 229.5 + 7.1 (s.e.) ms (10.47?1.10) and 236.9 + 17.3 (s.e.) ms (11.10?1.20). From the results of figure 6, it is clear that a bee having flown through the tunnel with the e-vector illumination transverse in the first half of the tunnel and axial in the second half signals a direction of approximately 458, which is in between these two directions. This suggests that by illuminating a straight tunnel with two successive, mutually perpendicular e-vector directions we can simulate a flight through an L-shaped tunnel consisting of two perpendicularly oriented legs, each leg being half the total length. When bees fly in a simulated L-shaped tunnel, do they indicate a measure of the total distance flown (d ), or the `shortcut’ p (vector) distance (d/ 2) to the food source as illustrated in figure 8c? If they indicated the total distance, we would expect the waggle duration to be approximately 227 ms; if they indicated the vector distance, we would expect the p waggle duration to be in the vicinity of (227/ 2) ?160 ms. The GSK2256098 web measured mean waggle duration in the simulated L-shaped tunnel is 240.3 + 7.9 (s.e.) ms (12 bees, 12 dances, 94 waggles; figure 8d), which is significantly greater than 160 ms (t-test, p , 0.01), but close to the durations measured in the `straight’ tunnels (one factor ANOVA, p ?0.18). Thus, in the simulated L-shaped tunnel the bees signal the total distance flown, rather than the vector distance corresponding to the imaginary shortcut. The flight distances that these waggle durations would represent in outdoor flight are approximately 300 m for the distance to the food source in the straight tunnel and approximately 210 m for the vector distance to the food source in the L-shaped tunnel. These estimates of equivalent outdoor flight distances are obtained from calibrations of the honeybee’s odometer as described in [16].4. DiscussionThe ability to use polarized light for navigation or orientation has been demonstrated clearly and unequivocally in walking animals such as the desert ant [21], the desert wood louse [22] and the dung beetle [23,24]. This has been achieved by showing that the direction of locomotion of a homing desert ant, or of a dung beetle departing with its treasure, can be systematically altered by changing the direction of the e-vector of the overhead illumination. However, this ability has so far not been demonstrated in honeybees–or, indeed, in any other airborne animal–because of the obvious technical difficulties associated.Dashed line represents the average p of the mean waggle durations recorded in conditions (a,b), and the lower dashed line indicates (1/ 2) times this value. (Online version in colour.)the durations of waggle dances of bees that had returned from a 12 m long tunnel illuminated with polarized light that was oriented either axially (figure 8a), or transversely (figure 8b), or transversely for the first 6 m and axially for the final 6 m (figure 8c). The mean waggle duration recorded with axial polarization (216.4 + 1.9 (s.e.) ms; 11 bees, 11 dances, 100 waggles) is not significantly different from that recorded with transverse polarization (234.4 + 8.3 (s.e.) ms; 17 bees, 17 dances, 102 waggles) (t-test, p ?0.07). The average of these two durations is 227.3 + 6.4 ms. The waggle durations recorded in each of these conditions are very similar to those recorded for flights under the open sky in Experiment 1. Those durations, recorded on 13 March 2008, are: 191.9 + 20 (s.e.) ms (9.15 ?.30), 229.5 + 7.1 (s.e.) ms (10.47?1.10) and 236.9 + 17.3 (s.e.) ms (11.10?1.20). From the results of figure 6, it is clear that a bee having flown through the tunnel with the e-vector illumination transverse in the first half of the tunnel and axial in the second half signals a direction of approximately 458, which is in between these two directions. This suggests that by illuminating a straight tunnel with two successive, mutually perpendicular e-vector directions we can simulate a flight through an L-shaped tunnel consisting of two perpendicularly oriented legs, each leg being half the total length. When bees fly in a simulated L-shaped tunnel, do they indicate a measure of the total distance flown (d ), or the `shortcut’ p (vector) distance (d/ 2) to the food source as illustrated in figure 8c? If they indicated the total distance, we would expect the waggle duration to be approximately 227 ms; if they indicated the vector distance, we would expect the p waggle duration to be in the vicinity of (227/ 2) ?160 ms. The measured mean waggle duration in the simulated L-shaped tunnel is 240.3 + 7.9 (s.e.) ms (12 bees, 12 dances, 94 waggles; figure 8d), which is significantly greater than 160 ms (t-test, p , 0.01), but close to the durations measured in the `straight’ tunnels (one factor ANOVA, p ?0.18). Thus, in the simulated L-shaped tunnel the bees signal the total distance flown, rather than the vector distance corresponding to the imaginary shortcut. The flight distances that these waggle durations would represent in outdoor flight are approximately 300 m for the distance to the food source in the straight tunnel and approximately 210 m for the vector distance to the food source in the L-shaped tunnel. These estimates of equivalent outdoor flight distances are obtained from calibrations of the honeybee’s odometer as described in [16].4. DiscussionThe ability to use polarized light for navigation or orientation has been demonstrated clearly and unequivocally in walking animals such as the desert ant [21], the desert wood louse [22] and the dung beetle [23,24]. This has been achieved by showing that the direction of locomotion of a homing desert ant, or of a dung beetle departing with its treasure, can be systematically altered by changing the direction of the e-vector of the overhead illumination. However, this ability has so far not been demonstrated in honeybees–or, indeed, in any other airborne animal–because of the obvious technical difficulties associated.
