Lateral asymmetries during escape behavior in a species of teleost fish (Jenynsia lineata)

Lateral asymmetries in the direction of turning during escape behavior in a species of teleost fish, Jenynsia lineata, are reported. When faced with the visual image of a simulated predator, approximately half of the individuals exhibited a significant bias to turn rightwards or leftwards, and the asymmetry tended to be retained when the same fish were retested 1 month later. Some morphological characters (pectoral fin rays, scales in natural row, supraorbital, preopercular, and postotic pores) were measured to check whether the degree of behavioral asymmetry was correlated with morphological fluctuating asymmetries associated with environmental stress or reduced heterozygosis. The results showed that it was not. The implications of these results for the interpretation of behavioral lateralization at the individual and population level are discussed.