Male Ornamentation in the European Minnow (Phoxinus phoxinus) Signals Swimming Performance



The association between male secondary sexual ornamentation and male quality has been under intensive study for decades. It has been shown that male ornaments in fish indicate a variety of physical and genetic qualities. However, only few studies have investigated whether male ornaments signal locomotor performance, a trait that is expected to be vital for individual fitness in the nature. In this study, we sampled two populations of European minnow (Phoxinus phoxinus), a cyprinid fish species with spectacular and colourful male breeding ornamentation, and examined the association between male ornaments (tubercle number, lateral darkness and abdominal redness), swimming performance, and three fitness-related traits, body length (LT), condition factor (K) and gonadosomatic index (GI). We found that male tubercle number and abdominal redness were positively correlated with their swimming performance. In addition, these two ornaments were correlated with male fitness-related traits, which in turn were also directly associated with the swimming performance. In general, these results suggest that in the European minnow male ornamentation may act as an honest signal of several fitness-related traits and locomotor performance in the nature.