EVEN CRABS NEED LOVE

I can't help but think of my friend, CrabbyMan when I saw this article.  Only because of his name!!  Just thought this was very interesting, we flex our muscles too, put our best side forward, make the moves, puts attracting the opposite sex in a whole new light. We might even learn some new moves! --John 

Crabs wave the long arm of love

Wednesday, 16 January 2008 Dani Cooper
ABC

Male fiddler crabs and their human counterparts have a lot in common when it comes to attracting members of the opposite sex, says an Australian researcher.

Martin How, from the  Australian National University (ANU), has shown for the first time that these animals change their body language depending on the distance between them and their true love.

The findings, to be published in  Animal Behaviour, are based on a study of the tiny fiddler crab, Uca perplexa, which lives on the mudflats of Bowling Green Bay, near Townsville in North Queensland.

Claw waving in the male fiddler crab replicates human communication, says How, who is with the  Australian Research Council Centre of Excellence in Vision Science at ANU's Research School of Biological Sciences.

"We know that in everyday life attracting the attention of a distant person involves gestures and vocalisations different from those used when that person is nearby," he says.

During two weeks observing and filming the fiddler crabs, How found the male changed the movements of his large brightly coloured claw as the female crab moved closer.

"Over distance he uses these very flamboyant, very conspicuous claw-waving displays [that say] 'I'm over here come and see me'," How says.

"And then when the female approaches very close he adjusts those displays so they are less broad and flamboyant and more coaxing."

The study is the first to show movement-based signalling in animals changes according to the distance over which they are communicating.

IRRESISTIBLE

 

This "coaxing" behaviour includes a bit of old-fashioned showing off with the fiddler crab "performing unflexed leg lifts", "raising the body off the ground" and the irresistible "slow claw lift".

How says this is the male crab's way of showing his qualities in the hope of convincing the female to follow him into his burrow to mate.

The PhD student says because the males signal from beside the burrow, the highly conspicuous, long-distance signalling can also indicate to females an escape route from a potential predator.

As part of the study How induced courtship interactions by dragging a tethered female fiddler crab across the mudflat surface to a male burrow.

The response in the focal male was filmed simultaneously from above and crab-eye level.

How says carrying and waving the major claw is energetically costly for the male and courtship signalling cuts into valuable feeding time.

The change in the male's claw movements may also be a way of balancing energy costs with the perceived probability of winning over the female and reproducing.