Fig. 4. (A) Photograph depicting the experimental area taken from behind F9.5, where the feeder can be seen in the foreground. The hemispherical bush in the centre is a rhododendron plant (white arrow; R.sp.1 in Fig.3), and the surrounding trees are horse chestnuts (black arrows labelled with individual numbers corresponding to those in Fig.3). The ants returning from F9.5 walk in a direction coinciding approximately with the right edge of R.sp.1. The yellow dots on the ground running back from the feeder are vial caps placed on the path taken by the ant. (B) The same landscape but with screen A mounted in the experimental area. (C) The same landscape but with screen C mounted in the experimental area.