Figure 1. Flower models used in the experiments.

A) Each model is named with 2 letters, where the first letter refers to the colour of cross mark and the second letter refers to the colour of the background “corolla” (B: dark blue; Y: dark yellow; b: bright blue; y: bright yellow). B) Relative catches (photon catches relative to a white standard -ws-) versus Colour distance (in the perceptual colour space of a hawkmoth) for the 4 colours used in flower models. See methods section for calculations.