PMC

a) The output of compound search - plant category; b) The output of compound search - biological activity category; c) The output of compound search - plant, amount present & family category; d) The output of biological activity search category; e) The output of plant name search category for common name field; f) The output of plant name search category for binomial name field; g) The output of part and family name search category for part of plant field; h) The output of part and family name search category for family name field

Search distributions of ants in field experiments. a Only movement in the nest-feeder axis was evaluated to extract turning points comparable to those in the channel experiments (see “” and legend Fig. ) and to construct the density plots shown. Arrows point to peaks and shoulders in the search distribution of the field visual group; arrow positions are at 10, 11, 13 and 15 m. b Corresponding box-and-whisker plots. With the alley of landmarks present, ants without manipulations (green, field visual group) had a distance search centre at 10.90 m (+0.65 m; −0.98 m) and ants that had their ventral and lateral eyes covered (red, field “blind” group) had their distance search centre at 9.59 m (+0.96 m; −0.4 m). Ants that were trained and tested without landmark alley and without eye manipulations (blue, field control group) had their distance search centre at 9.81 m (+0.61 m; −0.51 m). c Only the first turning points were evaluated from the same data set. The field visual group had the first turn median at 11.77 m (+2.12 m; −0.91 m) and the field “blind” group at 10.46 m (+0.91 m; −0.66 m). The field control group had their first turn median at 10.39 m (+0.67 m; −0.45 m). The search of the field visual group differed significantly from the searches of the two other groups (p < 0.01 against both other groups, ANOVA with Kruskal–Wallis post hoc test). d Two-dimensional search density plot of the field visual group. e Landmark alley seen from just above the nest entrance. f Two-dimensional search density plot of the field “blind” group. Details of the presentation are as in the previous figures

Search distribution characteristics (a), and search areas (b) of field searches. Details of the box plots are as in the previous figures, including colour identification of experimental groups. a For each individual ant, the search centres were calculated along the nest-feeder axis (abscissa, longitudinal distance) and along the axis perpendicular to it (ordinate, lateral distance) from all the x and y values in the search trajectory, including the box-and-whisker percentiles. Medians of all animals in an experimental group are shown to characterise the search distributions (e.g. the whisker at 5 m longitudinal distance represents the median of all 90 % percentiles in the field visual group). Note in the field visual group (green), the shift of search centre to 1.36 m (0.13 m lateral distance) along the landmark alley and the much increased longitudinal spread of the search distribution (3.21 m between 25 and 75 % percentiles, compared to 1.59 and 1.17 m in the field “blind” and the field control groups, respectively). Search width was reduced, by comparison (1.20 m between 25 and 75 % percentiles, compared to 1.36 and 1.78 m in the field “blind” and the field control groups). The landmark alley is drawn to scale on top of the search characteristics’ “crosshairs”. b Search areas were not altered by the presence of leading structures. Vertically hatched boxes indicate experiments with the landmark array present

Reliability of target selection by an FEF neuron during feature search. A, Spike density function of the neuron when the target (thick lines) or distractors (thin lines) of the search array fell in its receptive field during easy (solid lines) or difficult (dashed lines) feature search.B–F, Reliability calculations during easy search are represented by ●, and calculations during difficult search are represented by ○. All other conventions are as in Figure.