The ultimate in mating displays. ::waits for billytea to show up and contradict him::
There are so many criteria to decide which mating display should be the ultimate. There are those by which it would be the peacock. I think some of the birds of paradise offer more beautiful displays myself; and my tastes really run more to the charming absurdity of the blue-footed booby. But I think I shall declare the peacock to be the ultimate lekker. His display is undeniably remarkable; more than that, I can't think of another animal whose commitment to the laydeez is more detrimental to his own chances of survival. His display isn't just beautiful, it's also a real bugger to carry around. Imagine trying to escape a hungry tiger with that trailing behind you. (Peacocks moult their trains after the breeding season.)
Of course, this means that the display is not just major fabulosity, it's also a reliable signal of fitness. Surviving with one puts a bird a cut above the rest. (In addition, a parasite- or disease-ridden bird will have their condition make itself known in the train, through dullness, scruffiness or asymmetry.)
I tell a lie, however. The male with the greatest disregard for his own safety is the redback spider. As with many other species of spider, the female eats the male after mating if she can. The male redback, however, doesn't try to escape; he actually somersaults into the female's jaws, throwing other males out of the way if necessary. Indeed, to reach the female's genitalia, he has to. So perhaps I must qualify that the peacock is the animal most reckless with his own safety without actually having a death-wish.
Other thoughts: I have been COMM'd for the mating habits of the octopus, the blue-footed booby, the antechinus and the echidna. But never the peacock.
And see? Now I feel better. Hee. Antechinus.