Fiddler crabs reveal honesty is not always the b...( Dishonesty may be more widespread in...)

Dishonesty may be more widespread in the animal kingdom than previously thought. A team of Australian ecologists has discovered that some male fiddler crabs "lie" about their fighting ability by growing claws that look strong and powerful but are in fact weak and puny. Published this week in the British Ecological Society's journal Functional Ecology, the study is the first direct evidence that crabs "bluff" about their fighting ability.

The signals animals send each other about their fighting prowess - and the honesty of these signals - is a long-standing problem in evolutionary biology. Despite their size - they are just two centimetres across - fiddler crabs are ideal for studying dishonesty in signalling. This is because males have one claw that is massively enlarged (which they use to attract females or fight rival males) and if they lose this claw during fights they can grow a replacement. In most species the new claw is identical to the lost one, but some species "cheat" by growing a new claw that looks like the original but is cheaper to produce because it is lighter and toothless.

According to lead author of the study, Dr Simon Lailvaux of the University of New South Wales: "What's really interesting about these 'cheap' claws is that other males can't tell them apart from the regular claws. Males size each other up before fights, and displaying the big claw is a very important part of this process."

Dr Lailvaux and colleagues from the Australian National University measured the size of the major claw in male fiddler crabs, and two elements of fighting ability - claw strength and ability to resist being pulled from a tunnel. They found that while the size of an original claw accurately reflects its strength and the crab's ability to avoid being pulled out of its burrow, this relationship does not hold true for a regenerated claw.

"This means that while males can gain an idea of the performance abilities of mal
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