Waving robotic crab arm attracts females

Four sets of Robocrab arms wave to attract the attention of a live female. She eventually runs towards the set on the bottom left hand side of the screen. Female fiddler crabs prefer males who can out wave their neighbours, report researchers at the 13th Congress of the European Society for Evolutionary Biology. According to BBC report, male crabs advertise their quality as a potential mate to passing females by waving their large yellow claws. Using robotic arms, researchers evaluated how the size and speed of the waving claw affected mating success. The results may help explain why males protect their smaller neighbours. To the fiddler crab Uca mjoebergi, the Australian mudflats in the north of the country are a heaving dance floor, where a male must rely on his moves to attract a mate. Males stand outside their burrows and use their enlarged claw to attract females by moving it in circles. If a female likes the look of a male, she will come closer and disappear down his burrow in the sand, possibly staying to mate.