Fig. 3

Relative importance of floral cues of Taraxacum officinale (a) and Campanula trachelium (b) to Andrena bicolor. Responses (approaches + landings) of flower-naive females of the first and second generation to olfactory and visual cues (alone or combined) of host flowers or to empty controls in dual-choice bioassays. Numbers given at the right and left side of the bars indicate the absolute number of responding bees. Differences in responses for each dual-choice bioassay were assessed by an exact binominal test, P > 0.05 (n.s.), P < 0.05 (*), P < 0.01 (**), P < 0.001 (***)