Odonata colour: more than meets the eye?

Interpretations of behavioural visual cues, based on human perception of colour, may mislead because of the difference in our visual range compared to other animals. Investigations into ultraviolet (UV) reflectance have shown that this can be an important mode of communication in many animals. The present study focused on 10 species of British Odonata. Digital photography was used to capture images of UV reflectance of the body using a Schott UV pass filter to eliminate all other portions of the spectrum. Percentage cover of UV reflectance was determined and all but one of the 10 species sampled were found to reflect UV in one or both sexes. Most of the reflectance tended to occur on the ventral surface. Patterns of UV reflectance varied among species suggesting a variety of possible functions that are briefly discussed. A potential evolutionary mechanism for the development of UV reflectance in Odonata is proposed.