For whom the male waves: four types of claw-waving display and their audiences in the fiddler crab, Uca lactea

Some animals are known to use several different signals which convey different messages. In the fiddler crab, Uca lactea, I found that males performed at least four types of claw-waving display: lateral-circular, lateral-flick, rapid-vertical, and circular waving. The major audiences and the seasonal occurrence patterns of the displays differed among waving types. Lateral-circular waving (combinations of slow lateral extension, quick flexion, and circumduction of the major claw) was mostly performed to female audiences and was observed frequently in the breeding season. Lateral-flick waving (quick lateral abduction to the audience) was frequently performed to neighbor residents but rarely performed to females in the breeding season. Rapid vertical waving (rapid dorso-ventral protraction and retraction) was observed throughout the observation period and was most frequently performed to burrowless males. Circular waving (simple circumduction) was frequently observed prior to the breeding season and had no obvious audience in most cases. The results showed that males performed different types of claw-waving in different contexts. Males may have needed to use several different types of waving in order to transmit different messages. Digital video images relating to this article are available at http://www.momo-p.com/showdetail-e.php?movieid=momo091127ul01a, http://www.momo-p.com/showdetail-e.php?movieid=momo091127ul02a, http://www.momo-p.com/showdetail-e.php?movieid=momo091127ul03a, http://www.momo-p.com/showdetail-e.php?movieid=momo091127ul04a.