Four-Legged Butterflies

I’ve been enchanted by the insects on my buddleia plant this summer, especially Jiminy, the speckled bush cricket. He set up home there two months ago, and he’s hardly strayed from his favourite leaf.

Speckled Bush Cricket

Crickets have an amazing pair of back legs – long and muscular with spring-loaded knees, adapted to jump fast and far. They also have two more pairs of legs. Because, of course, insects have six legs. It’s the magic number.

But do they always? I can only see four legs on this Red Admiral butterfly. Peacock butterflies are the same.Red Admiral Butterfly Legs

Red Admiral and Peacock butterflies are part of the Nymphalidae family. Their front legs are so small they seem hardly there. You might just see them, looking like tiny, twin brushes curled in front of the body. They probably help the butterfly to taste, smell and communicate, but never to stand.

What about caterpillars? Isn’t it odd that baby butterflies have more than six legs? In fact, only the three pairs at the front are true jointed legs. Those grasping feet further back are called ‘prolegs’. They help the caterpillar move by hydraulic action. When it metamorphoses into a butterfly, the prolegs disappear. This caterpillar has five pairs of prolegs.

Caterpillar Prolegs

So, that’s that. Insects have six legs – even when they don’t.

Of course, storybook heroes can flout the rules. The anthropomorphic ants in Disney’s A Bug’s Life have just two legs and two arms. And Eric Carle’s famously peckish Very Hungry Caterpillar has an odd arrangement of legs. These much-loved characters don’t need realism. They have an altogether different kind of magic.

Red Admiral Butterfly square

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