Conspicuous body coloration and predation risk in damselflies : are andromorphs easier to detect than gynomorphs?

The coexistence of multiple female colour morphs in damselflies remains poorly understood. Typically, one of the female morphs is coloured like the mate (andromorph), while the other morphs are not (gynomorphs). Andromorphs, by resembling males, are thought to benefit from avoiding male harassment. Some authors have proposed that this benefit is offset by a higher probability of detection for andromorphs compared to gynomorphs owing to differences in body colouration. We experimentally tested detectabilities of the different female colour morphs using human observers as model predators. In contrast to expectation, detection probabilities for andromorphs and gynomorphs were equal. We discuss the use of survival probabilities to test for differences in predation rate between female morphs and consider whether human predators are representative models for the natural predator guild of the studied damselfly.