Belfast Telegraph

On a wing and a prayer... how butterflies send secret signals

By Michael McCarthy

As winter has begun this week and we face three months of cold and wet, I thought I would write about butterflies, to remind us of sunshine and warmth. A new butterfly guide has just been published which is, to use the old seducer's phrase, not like all the others.

Seeing Butterflies by Philip Howse, a retired Professor of Entomology at the University of Southampton, shows you, not how to identify species, but how to find pictures in the wings of butterflies and moths of other creatures, from the real world.

These are - Howse is convinced - real images of other creatures. The author maintains they are not simply accidents.

On the contrary, the pictures on Lepidoptera wings have evolved there through natural selection, Howse believes, as a direct means of helping butterflies and moths escape from insect-eating predators, such as birds, by suddenly startling them and so gaining a millisecond in which to flee.

In the past, humans have not readily seen these images, as we look at Lepidoptera in a conventional way and usually from the same angle, as "set" specimens with their wings spread out; but birds and other predators may see them in a very different manner.

Nearly five years ago, Howse launched the idea with a groundbreaking book entitled Butterflies - Messages From Psyche, which illustrated some startling images, such as a snake in the wingtips of an atlas moth from south-east Asia, and an unmistakable fox's head in the wings and body of the eyed hawkmoth (found in Britain) when seen upside down.

I wrote about it then and I said I thought it was convincing - although scientific opinion was by no means universally convinced. One of Britain's leading butterfly experts said to me: "It's all mumbo jumbo."

However, another leading expert told me he thought Howse was on to something and the theory is gaining ground, to the extent that it is now warmly endorsed in the foreword to Seeing Butterflies by Jeremy Thomas, Professor of Ecology at Oxford and the doyen of British lepidopterists.

The new volume, which is exquisitely illustrated with photos of butterflies and moths from all over the world, takes the theory further. What Howse is doing, in effect, is creating a whole new branch of entomological science, and it has a name - satyric mimicry, meaning the use of images to make organisms such as butterflies appear ambiguous to an observer, just as the Satyrs of Greek myth - half-man and half-horse - would have been.

The "eye spots" on many butterflies are the most obvious example of this; the insect can suddenly show the face of a much larger creature.

But there are bodies as well as faces to be seen. To take another of our well-known butterflies, the small tortoiseshell, Howse says that the body pattern of a bumblebee is clearly discernible in the sequence of colour bands on the leading edge of the forewing - black, yellow, black, yellow, black, white - and I agree. A butterfly-eating bird might well avoid a bumblebee with a sting.

"Most people remain highly sceptical that insects mimic birds and other animals with which they share their environment," Howse writes. But he is convinced that they do - and Seeing Butterflies will surely convince others.

It is not only a beautiful book to look at, but it has the exhilarating feeling about it of discovery.

It is, indeed, not like all the other guides and many of Britain's growing band of butterfly-lovers will want to own it.

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