Fig. 4. Homing distances of experimental ants. The top panels show search density plots (abscissae, homing distance; ordinates, cumulated relative search densities between the first and sixth turning points; see Materials and methods), the bottom panels show box-and-whisker plots (medians of the initial six turning points; compare Fig. 1,bottom), derived from the same data sets (N=25 ants for each experimental situation). (A) The ants were tested immediately after the lengths of their legs had been modified at the feeding site, that is, leg lengths were normal during the outbound journey but manipulated during the homebound run (Test 1). (B) The ants were tested after re-emerging from the nest after previous manipulation. In this situation leg lengths were equal, though manipulated, during outbound and homebound runs (Test 2). The hatched box plots in the lower panel of A illustrate the search centres as predicted from the high-speed video analyses of stride lengths in normal and manipulated animals; for details see text. Colour code: red, stilts; blue, normal; yellow, stumps I; green, stumps II.