THE DESIGN OF A BEAUTIFUL WEAPON: COMPENSATION FOR OPPOSING SEXUAL SELECTION ON A TRAIT WITH TWO FUNCTIONS

摘要: Male fiddler crabs, genus Uca, have one greatly enlarged claw with which they court females and threaten fight other males. Longer claws are more effective signals but thought to be less weapons because the relative closing force at tip of decreases length. We studied morphology fighting in Uca terpsichores beebei found a mechanism that may resolve opposing selection for signaling ability. When males fought delivered gripping forces not tips tubercles on inner margins their claws' fingers. As grow, these remain relatively close apex gape. Consequently, mechanical advantage governs can only slightly increasing length allowing an signal powerful weapon. Animal exceptionally diverse form detail armature causes this diversity poorly understood. suggest designs often reflect compensatory patterns growth placement enhances weapon's overall utility multiple uses competition mates.