Large white butterfly caterpillars

 I sowed nasturtium (Tropaeolum majus) seeds this spring, partly for the flowers but also because I was hoping that large white butterflies might find them and lay eggs. They did, and now the foliage is disappearing fast, thanks to some very hungry caterpillars, A nostalgia trip really, because I remember watching exactly the same thing happening in my parents' garden, seventy years ago. Childhood nature experiences can last a lifetime.

Pale tussock moth caterpillar Calliteara pudibunda

 

We found this larva of a pale tussock moth crawling along the parapet of Prebends bridge, across the river Wear, in Durham.

Everything about it warned ‘don’t touch me’. It would present a challenge for most insectivorous birds, although cuckoos, with a gizzard that can cope with irritating hairs, sometimes eat them. Those deterrents inflict discomfort on tender human flesh too; finely barbed and filled with irritating fluid, they can cause dermatitis. Calliteara pudibunda was once a notorious pest of hop fields, which might explain naturalist Gilbert White’s journal entry for October 8th. 1781, noting that  ‘ …women and children have eruptions on their hands ….after they have been employed in hop picking’.  More recently, families from London’s East End, travelling to Kent for traditional hop picking work every autumn, would have been painfully familiar with these caterpillars, that they knew as ‘hop dogs’.

Pale tussock larvae are not picky about food plants and defoliate at least a dozen broadleaved tree species, including beech, hawthorn, sycamore and lime, all well represented along this riverbank. But, out of curiosity, I offered our captive some young shoots from the hop vine that twines through our garden fence. It had a nibble but was fully fed and only interested in finding somewhere dry and secure amongst the leaf litter, where it will pupate inside a cocoon woven from recycled defensive bristles.

Hatched from an egg laid last June, this wanderer - provided it hasn’t already been parasitised by an ichneumon wasp - should survive winter, metamorphosing as a beautiful pale grey moth next spring.

Alder moth caterpillar: a blast from the past

 It is almost exactly 50 years since I last found one of these: an alder moth caterpillar. Then, I was living in Warwickshire and it was curled up on a leaf, just as this latest one was, in a hedgerow in County Durham.

I have migrated north but so has Acronicta alni, except that it has extended its range more slowly. A  thorough guide to moths in County Durham published in 1986 doesn't list it, but now the alder moth is here, another insect species extending its range northwards, most likely in response to climate change.