Female preferences for single and combined traits in computer animated stickleback males

In many animal species, males have more than one secondary sexual character . Apart from theoretical considerations about the evolution of multiple tra its, there are almost no empirical studies on female mate choice decisions based on combinations of traits as opposed to decisions based on single tra its. Because three-spined sticklebacks are exceptionally well suited to be tested with computer animation technique, which itself fills the gap of ade quate test paradigms for multiple traits, we tested female sticklebacks for their preferences for both single and combined male traits. We used virtua l stickleback males that differed either in red throat coloration, courtshi p intensity, body size, or in combinations of these traits. The virtual mal e with increased redness was found to be preferred by females, whereas the male courting more intensely was not. The tests for combinations of traits revealed the more pronounced female preferences, the more traits were avail able to the females to judge male quality.