Sexual dimorphism of mate location in the long-toed salamander Ambystoma macrodactylum columbianum

In breeding systems characterized by scramble competition among males, theo ry predicts that the efficient location of mating partners is more importan t to males than to females as a component of mating success. We experimenta lly tested in the laboratory the hypothesis that breeding male long-toed sa lamanders (Ambystoma macrodactylum columbianum), which scramble for mating opportunities, are better able to recognize and locate potential mates than are breeding females. Males were more likely to enter traps containing fem ales than empty traps or traps containing males. Traps containing sponges s oiled by females were more likely to attract males than traps containing cl ean (control) sponges, suggesting that chemical cues may be sufficient for mate location by males. Females were no more likely to enter traps containi ng males than empty traps. Our results are consistent with the theoretical prediction that selection has been stronger on male long-toed salamanders t han on females in the context of capacity for recognizing and locating pote ntial mating partners.