Gross colour pattern is used to distinguish between opponents during aggressive encounters in a Lake Malawi cichlid

Abstract – The role of male colouration in the behavioural interactions of haplochromine cichlids has received much attention. Previous studies supported the role played by visual signals during interactions of rock‐dwelling cichlids, or mbuna, from Lake Malawi. It has largely been assumed that hue, and not pattern, is the primary signal encoded in male colouration; thus, the role of colour pattern has received less attention. We explored the use of visual signals during aggression in Labeotropheus fuelleborni by using identically and differently coloured opponents and by offering these opponents under coloured illumination. We presented two simultaneous opponents to males and found that the focal male’s responses depended upon opponent colour pattern; similarly patterned opponents received more aggression, even if presented under a hue‐obscuring light source. These results support findings that gross colour pattern may be more important than hue in interactions among the mbuna and further support an important role for visual communication in these fishes.