Belfast Telegraph

Unnatural weather brings out some natural beauties

By Michael McCarthy

Here's a remarkable butterfly story. When you first become interested in butterflies, you naturally enjoy their vivid colours and concentrate on recognising them. But as you become more involved, you start to look at subtler things.

One is the larval food plant of each species; if that plant isn't present for the caterpillars to munch, it's not very likely the butterfly will be. So, the caterpillars of several of our bright, orange-and-black fritillaries feed on violets and a wood without violets is likely to be fritillary-free.

Another is the species' scientific name, which will usually tell you something interesting about the insect (once you translate it from the Latin).

Thus, the second part of the scientific name for the black hairstreak, Satyrium pruni, tells you it feeds on blackthorn bushes (Prunus).

But one of the most interesting aspects is the species' overwintering strategy. Think about it. We see our butterflies mainly in the summer sunshine, but only two of our 58 species are immigrants from Europe's warm south: the painted lady and the clouded yellow. From one year to the next, the other 56 all have to survive the rigours of our winter.

There are four ways they can do it: as an egg, as a caterpillar, as a pupa or chrysalis, or as a fully formed adult insect.

Here's a piece of knowledge for when you're on Mastermind with butterflies as your specialist subject: 31 of our 56 species spend the winter hidden away as a caterpillar; 11 spend it as a chrysalis; nine go through it as an egg; and a mere five pass the cold season as an adult.

These five are the peacock, the small tortoiseshell, the comma, the red admiral and the brimstone.

Four of them perform a fascinating camouflage trick: with their wings closed, they look like leaves.

It is because they overwinter as adults that these five butterflies are the first ones we see when the warmth returns. They have no more growing to do.

Although I think of the brimstone and the orange tip (which overwinters as a pupa) as the first true spring butterflies, and look for them from March onwards, it is often an overwintering peacock that you will first see.

And here's the point: this year, the weather has been so mild that all five have been observed flying about in the first week of January (or, to be strictly accurate, the first eight days).

On January 1, a red admiral was seen; on the 2nd, a peacock and brimstones; on the 6th, a small tortoiseshell; and on the 8th, a comma.

According to Martin Warren, head of the charity Butterfly Conservation, this is unheard of.

"It's a remarkable event," he says. "We have no records of it happening before."

You can find the details on the charity's website, www.butterfly-conservation.org.

You might have thought it's been unseasonably warm in the past couple of weeks; but not half as much as our butterflies have.

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