Seasonal colour changes and shifting antipredator tactics in darters

Dull coloured, non‐breeding males of the darter Etheostoma flabellare ‘freeze’ in response to simulated predatory threat. As they enter breeding condition, colour changes are minor and antipredator behaviour does not change. Male E. blennioides , which develop bright green colours in the breeding season, also freeze in response to threats in both breeding and non‐breeding states. Male E. spectabile change colours dramatically when breeding, developing intense and contrasting orange, blue, yellow and red colours on their sides, fins and throats. In non‐breeding colouration, they freeze when threatened, but in breeding colouration they become less likely to freeze and more likely to flee. These results are discussed both with respect to the hypothesis that changing colours may require changing antipredator behaviour, and in terms of the probable degree of crypticity of these species. Details of the duration of immobility of ‘freezing’ fish and the pattern of subsequent recovery of activity level are also presented.