Saturday, August 11, 2007

Sexual selection

They say that sex is a powerful mechanism for the selection of behaviour, body shape and so on. I was recently in Cairns for a conference, and spent some time at the Esplanade. It is a stretch of mudflat. It is world famous for birds, but I saw more than birds. Small Fiddler crabs come out when the tide is well and truly out. The males have an oversized claw used for signally to females and rivals (I've learnt a bit watching David Attenborough!)

What is interesting is that with one claw useful for feeding is that they have to work twice as hard to munch mud as the females do. I don't know if it is really for status (winning fights or avoiding them with threats) or for impressing females (the crustacean equivalent of a porche?)

What price for spreading your genes? It doesn't seem that they suffer other than having to work hard for a feed. Sex it seems is powerful. Pictures to follow.

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