Fig. 4

Bioassays comparing the attractiveness of floral cues of Taraxacum officinale vs. those of Campanula trachelium to Andrena bicolor. Responses (approaches + landings) of flower-naive females of the first and second generation to visual cues alone or combined with olfactory cues of T. officinale compared with C. trachelium in dual-choice bioassays. Numbers within bars indicate the absolute number of responding bees. The difference in responses in each dual-choice bioassay was assessed by an exact binominal test and is shown at the left-hand side of the bars, P > 0.05 (n.s). Results of the Fisher’s exact tests used to compare the responses of flower-naive females of the first and second generation to each cue are shown at the right-hand side of the bars, P > 0.05 (n.s)