Fiddler crabs

There are about 100 species of fiddler crabs (genus Uca) in the world. Males have an highly exaggerated claw on one side and they use this for attacting females or fighting against their opponents.  They are one of the famous examples of sexual dimorphism which is probably caused by sexual selection proposed by Charles Darwin. Since 1999, I have been interested in their behavior, ecology and evolution and have conducted various researches such as reprodutive timing, mating system, and communication.