You canвЂ™t just pack a rhino beetle off to a new dojo, train it in a different martial art, and see how it performs. This study wouldnвЂ™t have been possible through direct experiments. As with the longswords, form and function are linked. Each one resists the types of forces that its owners typically experience, but threatens to snap or buckle when used in a different way. McCullough has found that the shape and structure of these horns are beautifully adapted to each beetleвЂ™s individual fighting style. During fights, it tries to slide this tip under its opponent, to lift and twist it off its branch. And the Japanese rhino beetle ( Trypoxylus dichotomus), much beloved of cartoons and anime, has an upwardly curving horn that ends in a pitchfork. The calliper beetle ( Golofa porteri) has a much narrower horn with a serrated edge, which it uses to lift and shove its opponent-more of a fencer to the Hercules beetleвЂ™s wrestler. (It can lift 850 times its own weight and, until recently, held the title of worldвЂ™s strongest animal. It looks like a disembodied pincer, and behaves like one too-males grab their opponents in a full-body hold, prise them off their perch, and toss them to the ground. The largest of them, the Hercules beetle ( Dynastes hercules) has a huge horn curving down from its back and another curving up from its head.

Unauthorized use is prohibited.Д®ach species of rhino beetle has its own distinctive headgear, and each fights in a different style. TheyвЂ™re for grabbing, throwing and shoving rival males off branches and tree trunks, in a bid to control access to females.

But thatвЂ™s not the case for the rhino beetles. In many animals, females choose males on the size and shape of their ornate structures. As their name suggests, the males of these large, powerful insects have elaborate horns on their heads.

Form followed function.Д®rin McCullough from the University of Montana found a similar trend among smaller but no less impressively armed combatants- rhinoceros beetles. A cutting weapon became more of a stabbing one. The central groove (the fuller) that lightened and strengthened the old models was replaced by a ridge (the riser) that conferred rigidity. Longswords evolved to be longer, narrower, and more pointed. Now, sword-wielders had to thrust their weapons into gaps and weak points-a new kind of fighting that required a different kind of blade. But once plate armour entered the battlefield, these slashes were useless. When longswords first came into use in the 13th century, knights mainly used them to slash through an opponentвЂ™s chainmail.

Hercules beetle rhinoceros beetle