Tag Archives: Batesian mimicry

Aah, it’s Duckling Time

Mute Swans with Cygnets
Mute Swans with Cygnets

Aah. Ducks with ducklings. Coots with Cootlings. Geese with Goslings. Swans with Cygnets. Moorhens with … chicks. Whatever the charmingly mediaeval diminutive nouns, it was a day for walking around the London Wetland Centre, enjoying the ‘sunny spells’ and the bright display of wild flowers, artfully seeded, and delighting in Mother Nature’s ability to conjure up fluffy sentimental feelings about roughly duck-shaped balls of fluffy down feathers.

Coot with Cootling
Coot with Cootling

I’d gone alone to see if there were any interesting dragonflies, but there weren’t many about: a warmer day is always better. But there was a Black-Tailed Skimmer basking on one of the ‘wildside’ paths.

Black-Tailed Skimmer
Black-Tailed Skimmer

Apart from that, I glimpsed one Hawker dragonfly – probably a Hairy dragonfly, as the only kind other than the Emperor seen there in the past month; and there were plenty of Common Blue and Bluetail damselflies about.

As for butterflies, it was alarmingly empty: a couple of meadow browns, a small white or two, and a female brimstone the highlight. My alarm at the lack of insects in general in England is growing. If it’s neonicotinoids – hot on the heels of all the earlier insecticides, many now rightly banned for their destructive side-effects on wildlife – then we are watching a manmade calamity. The BBC noted that some ditch water was toxic enough to be used, just as it was, as an insecticide spray for crops. The effect of that on dragonflies can only be imagined: a sad thing, as (living in rivers and ponds rather than on farmland) they have to some degree escaped the disaster that has all but eliminated our farmland birds, bees and butterflies.

But on a dead tree, wildside, was another fluffy-duckling sight, this time from a distinctly arboreal bird.

Parent and juvenile Green Woodpecker
Parent and juvenile Green Woodpecker

Two Green Woodpeckers, presumably a parent and a newly-fledged juvenile, were clinging to a dead tree, the parent a little higher up, the youngster apparently begging for food with open beak. The family drama went on for several minutes.

Two different Hoverflies on Burnet
Two different Hoverflies on Burnet

Tiny wildlife shows were visible on the flowers: here, two hoverflies of different species, busy being Batesian mimics of dangerously stinging wasps (but harmless as doves) are feeding, slow and relaxed in the sunshine, on the small flowers in a Great Burnet’s flowerhead. They didn’t seem at all bothered by each other, or by any risk from predators. But despite their glorious colours, it was duckling day today.

Book Review: Dazzled and Deceived, by Peter Forbes

Dazzled and Deceived: Mimicry and Camouflage, by Peter Forbes
Dazzled and Deceived: Mimicry and Camouflage, by Peter Forbes

The effect of natural selection on how animals look has attracted the
attention of naturalists from the birth of modern natural history, starting even before Darwin’s Origin of Species.

Visual appearance can affect an animal’s survival in numerous ways.
Camouflage makes it hard for predators to find a prey animal; warning coloration advertises that a potential prey is poisonous or distasteful; Batesian mimicry allows an edible species to pretend to be distasteful; and Müllerian mimicry allows a distasteful species to be sampled less often by young inexperienced predators, by resembling a more common distasteful species. And within these areas, there are infinite possibilities.

Butterfly Mimicry: mimics on the right, the imitated 'models' on the left
Butterfly Mimicry: mimics on the right, the imitated ‘models’ on the left

But as the cover art suggests, Forbes does not stop there.  Camouflage has military uses; and the history of two World Wars reveals extraordinary interactions between naturalists like Hugh Cott (author of the greatest twentieth-century book on camouflage, Adaptive Coloration in Animals, 1940) and Peter Scott with the military – Scott was a naval captain, so he had a foot in both camps.

Much of the book concerns the natural history and biology of butterflies – they include many of nature’s best mimics, and provide incredibly complex examples of visual evolution at work, as the mimic species adapts to each of the many geographic variants of the host or model species. It’s even possible for multiple forms to appear in a single brood. Forbes describes the research workers, their controversies and their heated opinions, right or wrong. Truth wins in the end, but that doesn’t prevent a messy process along the way, just as in evolution.

Today, new light is being shed on the mechanisms of mimicry and coloration in general by evolutionary developmental biology, which Forbes insists on calling “evo devo”. The result of such inquiry will one day be an explanation of the observed, very complex, natural history at multiple levels – genetics, developmental biology, visual appearance, and natural selection, all of which will have to fit together exactly. Pieces of the puzzle are becoming clear, as in the genetic and developmental mechanisms for producing eye-spots. These can be “impressionistic” – they do not have to mimic a cat’s face, as long as a wing-flash gives a bird predator an illusion of eyes-suddenly-jumping-out-at-me; for we suppose that birds have
an escape reaction triggered in some such way. Thus the explanation must take into account ecology too – the behaviours of both predator and prey are needed to explain why eyespots evolved.

Forbes can’t resist putting an artistic and literary take on the natural
history and science: Sir Ernst Gombrich the art historian was deeply
fascinated by visual illusion, while novelists like Vladimir Nabokov (a keen naturalist) were intrigued by truth and lies. Sometimes the analogies go rather far from natural history (electronic warfare is a case in point: it may be deception but it certainly isn’t visual). But Forbes is always precise, and invariably entertaining.

Buy it from Amazon.com  (commission paid)
Buy it from Amazon.co.uk (commission paid)