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Hairy little caterpillars on the move

Friday, 28th September, 2018 5:00pm
Hairy little caterpillars on the move

The hawkmoth caterpillar and his furry friends are on the move in search of a spot to pupate and overwinter.

Wildlife with an amateur observer

I’M meeting some quite interesting characters on my walks these days. Fully fed, many species of caterpillar are on the move now looking for somewhere to pupate and overwinter. 

I’ve moved so many of them off our narrow road, where they are in danger of being run over, to the safety of an adjacent field. And, of course, I get the opportunity to examine them up close while so doing.

The hawkmoth caterpillar in the accompanying photograph underwent quite a transformation when I picked it up. 

It pulled its head back into its body, swelling up markings on its skin to display its quite fierce looking fake ‘eyes’ which it uses to scare off predators.

The elephant halkmoth is not the only caterpillar with the ability to undergo an almost magical transformation to defend itself. And many other species also use chemicals to deter predators. 

Acid Attack

The puss moth is a fairly large white insect with a wingspan of 7cm. It is rather furry, with a cat-like appearance face-on, which probably accounts for its name. 

If the puss moth caterpillar is touched or irritated in any way, it raises its two tails and pushes a pair of pink threads out them which curl and lash about in an effort to frighten off parasitic flies or wasps which seek to lay their eggs on it.

The puss moth caterpillar also has another secret weapon – it can squirt a jet of formic acid from a gland just under its head. 

When under attack from a predator, it emits this acid which is sometimes enough to put the feeding bird off its prey. Cases are known of people inspecting a puss moth caterpillar too closely and getting an eyeful of acid (it is painful but not too dangerous). 

The lobster moth is a rather plain brown insect. Its unobtrusive colouring provides good camouflage when it is at rest. 

Its caterpillar feeds on beech, poplar, aspen and birch leaves and its appearance is quite extraordinary. 

The lobster moth caterpillar looks remarkably like an ant when newly-hatched. This may grant it some protection as not many predators relish eating ants. 

When fully grown, this unusual caterpillar looks a little like a spider or crustacean – more or less like a wonky mini-lobster on a tree – which gave rise to its curious name. It also has the ability to squirt formic acid from beneath its head.

 

Poison

The garden tiger moth is dramatically coloured with brick-red, black-spotted hind wings and white, chocolate-blotched fore wings. 

There are few moths more unpalatable to potential predators and the garden tiger moth’s strong colouring warns insects of this.

The garden tiger moth’s body tissues contain several different chemicals, including a kind of heart poison. Its caterpillar acquires these substances while feeding on plants which contain them in their leaves. 

The garden tiger also manufactures some poisons of its own – including a histamine-like substance. These poisons acts as powerful deterrents to insects, however, the amount of poison in an individual garden tiger moth is too small to affect a human. 

 

‘Woolly bears’,

The wonderful hairy caterpillars of the garden tiger moth, known as ‘woolly bears’, appear in springtime, and get more and more brightly coloured as they grow. 

They bask in the sun and scientists believe the sun’s warmth helps to makes them more active and able to feed more rapidly. 

They also feed for a short time in autumn before pupating for the winter. These caterpillars move very quickly and I’ve almost lost a few of them during ‘rescue operations’.

Another member of the tiger moth family, the cinnabar moth, also advertises its nasty taste and poisonous effects though its striking warning colouration. 

The cinnabar moth is quite unmistakable with its red and black markings – the scarlet red gaining it its cinnabar name. 

The caterpillar of the cinnabar moth also has warning colour patterns, of yellow and black markings. The principal food of the cinnabar moth is ragwort from which it acquires its poison. 

This has been a bumper year for ragwort so we should see an explosion in cinnabar numbers next year. 

So do keep your eyes peeled for caterpillars on the move. They are truly fascinating creatures.

 

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