Direction and length of failed and successful trips in the light and in the dark.

The three measurements – direction taken (correct or wrong), trip length, and trip outcome (failure or success) show that, in the light, most (79.8%) of the experimental (unidirectional) laden workers took the correct direction. Once in the correct direction, their course as far as the return bridge (successful) was as direct and straight as that of the controls (bidirectional in the light). The comparison between the control group in the light (experiment 1) and the control group in the dark (experiment 3) reveals that the absence of light handicapped orientation, but did not stop the ants from foraging effectively.