Flights of fancy
Butterflies’ haphazard flight is to befuddle predators – but like everything else, it could be designed to delight humans.
Amazing things about butterflies.
Name game
Let’s start with the name butterfly. Some say it’s because they land on and steal butter (and some even say those dairy-pilfering insects are witches in disguise). Others think it’s a corruption of flutter-by, or that Dutch scientists named it after the look of the bug’s faeces, but the most common explanation suggests it’s a tribute to the yellow hue of the male brimstone species.
Air miles
Each one weighs less than a single gram, but every spring painted lady butterflies migrate here from sub-Saharan Africa, and back again in autumn. The 9000-mile round-trip isn’t made by individual insects but by successive generations: each painted lady flies several hundred miles, lays eggs, and its young continue the journey, often riding the wind at altitudes over 1500 feet.
Gotta catch ’em all!
The swallowtail – Papilio machaon britannicus – is our biggest native butterfly, with a 3½-inch wingspan richly patterned like a Tiffany lamp. It’s a rare beauty localised to the Norfolk Broads where its caterpillars feed on milk-parsley, producing horns and an odour if threatened – just like the Pokémon Caterpie character this genus inspired.
Ganging up
A group of butterflies can go by many names – a wing, a flight, a flutter, a rabble, a rainbow or a kaleidoscope.
Fog of war?
In the 1940s a mustard-yellow cloud was spotted crossing the Channel. Observers feared it might be chlorine gas, but it was a swarm of clouded yellow butterflies (above) headed for the chalk grasslands of southern England. One report noted ‘the flight was on a front of about 50 miles, and that there must have been well over a hundred thousand butterflies taking part’. In warm autumns you may spot one as late
as November.
Scale up Butterfly wings are transparent: the colour comes from thousands of tiny scales reflecting light.
Metamorphosis
A butterfly is just the final stage of a mind-boggling life cycle which begins with a tiny egg glued to a leaf. It hatches into a caterpillar which eats voraciously (as Eric Carle taught us), splitting and shedding its skin four or five times as it grows: some caterpillars end this stage 100 times bigger than they started. Next, it retreats into a chrysalis where it gets ‘rebuilt, like a Lego model’ according to Anne Sverdrup-Thygeson (author of the brilliant book Extraordinary Insects) before it cracks it way out as a butterfly, unpacking damp and crumpled wings which it pumps to full size with liquid from its abdomen, and dries. Then it launches to find a mate and begin it all again.
Some like it hot
Butterflies are cold-blooded and can only fly if the temperature is into the double digits celsius. Lepidoptera (which also includes moths) are found on every continent on Earth except Antarctica, and some species like the brimstone can survive a British winter. They enter a state of torpor and produce antifreeze chemicals to stop their blood solidifying; you might even spot one with its wings covered with ice-crystals.
Eye for an eye
Many butterflies, like this peacock, have distinctive circular markings on their wings. They’re designed both to deter attack by looking like the eyes of a predator, and to direct any strike away from the insect’s body. A butterfly can survive with a torn wing, but not without a head...
Tasty feet
Before laying eggs, butterflies use their feet to ‘taste’ whether the leaf they’ve landed on will suit their caterpillar’s appetite. Some species like the swallowtail are very picky eaters and will eat only one kind of plant. Butterflies can’t bite or chew; instead they use a long proboscis (pictured left), to drink nectar from flowers, or liquids from rotting fruit, puddles, or even carrion.
Con artist
The large blue butterfly is a master of disguise: as a larvae it creates a scent that exactly matches that of a red ant. The unsuspecting Myrmica sabuleti take it into their nest and tend to it as one of their own; as thanks, it starts to eat the ant larvae, later imitating the clicking song of an ant queen so the workers leave it alone, even as it tucks into their young. The beautiful butterfly is rare here – to the point of vanishing in the 1970s – but has successfully been reintroduced to sites in the south west of England.
Net gains
Famous butterfly chasers include PM Neville Chamberlain, the clown Grimaldi and Lolita author Vladimir Nabokov who filled a cabinet at Harvard University with butterfly penises: they’re one of the best ways to differentiate species that otherwise look identical. Writing in The New Yorker he admitted ‘few things indeed have I known in the way of emotion or appetite, ambition or achievement, that could surpass in richness and strength the excitement of entomological exploration’.