Female preferences for conspecific and heterospecific wave patterns in a fiddler crab

A female preference for a conspecific over a heterospecific mating signal is seldom questioned. The ability of females to differentiate between conspecifics and heterospecifics, however, requires testing because we know, from the handful of studies that have examined this process; it is not as simple and easily achieved as once thought. This study shows that, in a fiddler crab, females preferentially approach conspecific over heterospecific signals when only the first part of a two-part conspecific signal is produced. When the full two-part conspecific signal is given, however, females do not prefer it to an allopatric heterospecific. This is the first demonstration using controlled experimental stimuli that wave form can be used for conspecific recognition in a fiddler crab. Our results also show that the process of conspecific recognition is more complex than previously assumed.