In three other populations where the males did initiate courtship with the conspicuous zigzag dance described by Tinbergen, cannibalism was never observed. In this social environment, males can use conspicuous courtship displays without the risk of losing their fertilized eggs. Thus courtship behavior appears to be an adaptive characteristic that may evolve differently in different social environments. By comparing different populations within a species, behavioral ecologists have successfully tested hypotheses about the adaptive significance of behavior.