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.

Ants in the compost bin

 We've been composting garden and kitchen vegetable waste in 'Dalek' bins like this for decades, but this year was the first times that we've had one taken over by nesting black ants. 

They moved in during those unusually cold weeks of early summer, probably because the warmth of decomposition in the bins provided the only location in the garden with enough heat for them to breed.  Textbooks say that they need a temperature of 10C to become active and 20C to raise a brood.

Watching their progress in the bins has been fascinating because the temperature inside rises very rapidly when the sun comes out and falls equally rapidly on dull wet days and in the evening, so they seem to be constantly moving their brood around to the optimum positions in the bin. At one point I thought they had left, but it seemed that they just moved their larvae and pupae deeper into the compost, in a cooler part of the bin. They shift their brood with remarkable speed when I lift the lid and light floods in - they can move a couple of hundred pupae, by carrying them in their jaws, in a few minutes.

Their larvae are translucent, but as they  pupate they spin a silken coat.

Lately, winged males have started to hatch so before long a queen will take to the air, followed by a swarm of males on the nuptial flight. After mating she will start a new nest, while most of the males will become food for swifts that swoop over the garden. 

Orange-sided comb-horn - a colourful daddy-long-legs

 The two commonest craneflies - Tipula oleracea and T. paludosa - are dull-coloured insects but this female orange-sided comb-horn Ctenophora pectinicornis has an orange and black colour scheme that gives it a hint of menace. We found it in old deciduous woodland on the bank of the river Wear in Durham city. The larvae (leatherjackets) of the two commonest craneflies feed on grass roots in pastures but the larvae of this woodland species feed on decaying fallen timber. 

As is so often the case, this specimen has lost a limb. Easily shed limbs might well be a last resort escape strategy, from the beak of a bird or the web of a spider.

Ox-eye daisy abundance

 I often whizz past, at 60 mph, motorway embankments that are covered with flowering ox-eye daisies, but it's not so often that I get a close look at these wild flowers in such abundance beside a footpath. This fabulous display covers an embankment in Hexham in Northumberland, on edge land between the railway line and a retail park road. It is absolutely stunning. 

Curlews

 These anxious curlews accompanied me on part of a walk in the Deerness valley, County Durham last week. They must have recently hatched young because they were highly agitated, with those yelping calls that they make when anything threatens their nest site. 

The weather is cold, wet and windy and they have crow predators to see off. They are nesting fields that I hope will be cut for hay, rather than mown early for silage. I've seen curlews raise successful broods in the same place in previous years, so fingers crossed.

Dung beetle aka dumbledor aka dor beetle aka lousy watchman

 Some more pictures of the dung beetle described in today's Guardian Country Diary

' Deerness Valley, County Durham

Waiting for the clip-clop of hooves to fade away, using a polythene bag as a glove, I picked up a tennis ball-sized, steaming lump of horse manure. Checking that no one else was around – this kind of old-school natural history might seem a tad eccentric to a casual passer-by – I hurried home: I had dung beetles to feed.

 

I’d found them on the edge of a pasture and, coincidentally, had recently been reading The Sacred Beetle, Jean-Henri Fabre’s century-old account of the breeding biology of scarabs, including our native species. Could I witness what the great French naturalist first described in such fascinating detail? Fabre, meticulous observer, curious experimentalist, cautious interpreter of facts, spent years studying these ‘dealers in ordure’ whose coprophilous habits make them an agricultural asset. One study has estimated their value to the UK cattle industry, as soil improvers and recyclers of dung, at £367m per annum.

 

My captive Geotrupes stercorarius, also commonly known as dor beetles, dumbledores or lousy watchmen (they often host parasitic mites), fell out of the collecting tube onto their backs, revealing beautifully iridescent amethyst-violet undersides.

 

They have endearing parenting skills; Fabre discovered that both sexes share in tunnelling and nest preparation. They clambered over the ball of dung in the vivarium, pausing to saviour it before dropping into the grass, then digging with flattened fore-legs, forcing themselves into the soil with powerful thrusts of spiny hind limbs. Clumsy on the surface, they’re superbly equipped for subterranean life. Within a minute they had disappeared.

 

Fabre’s account describes how they dig downwards, excavate side-tunnels provisioned with what he called ‘sausages’ of ordure dragged down from the surface, then the female lays an egg in each. The next generation should emerge in autumn.

 

‘The mind, wrote Fabre, ‘is an activity, not a repository’. In some respects, naturalists live in a golden age, with so many resources available for identifying and naming what we find – AI, web sites, apps, on-line keys, social media study groups – but there’s more to natural history than compiling an inventory of biodiversity. Nothing comes close to that pleasure, first experienced in childhood, of first-hand observation, marvelling at lives of other creatures that share our planet. '

 

Here is a short YouTube video of the beetle digging its tunnel 

Birch sawfly

 At first glance I thought this was a bee, resting on a gorse flower - then I noticed those club-tipped antennae, the un-beelike way it held its wings and its lethargic behaviour. It's a dark birch sawfly Trichiosoma lucorum, one of the club-horned sawflies. Its larvae feed on birch leaves.

I found it in this gorse thicket, with birches nearby, on the north bank of the river Derwent at Blanchland in Northumberland.

Waiting for a breeze

A field on the edge of Durham city, full of thousands of dandelion 'clocks', waiting for a breeze to carry their plumed seeds aloft. 

The final phase in the dandelion life cycle, when the flowers are transformed into silvery spheres, dandelion ‘clocks’ composed of seeds each equipped with its own parachute, is a magical moment when an umbrella of hairs, a pappus in botanical parlance, carries the seed up and away on the wind, to pastures new. At sunrise in late spring, whole fields can shimmer with silvery dandelion clocks as their pappuses expand as they dry in the sun’s heat. Sometimes goldfinches arrive to feed on the seeds, releasing wraiths of downy seeds, ethereal ‘witches’ gowns’, into the rising thermals.

The name dandelion is a corruption of the French dent-de-lion, lion’s teeth, describing the deeply serrated leaf edges, but botanist Geoffrey Grigson also collected 52 parochial county names. Some, like Devil’s Milk-plant (Kirkudbrightshire), refer to the bitter milky sap. Many, like Schoolboys’ Clock and Tell Time (both Somerset) allude to the childhood game of guessing the time by the number of puffs needed to blow away all its seeds from the ‘clock’. Monk’s head (Wiltshire), likening the bare seed head left behind to a monk’s bald pate, is said to have medieval origins, while Wishes (Wiltshire) stems from the belief that the airborne seeds carry away hopes and dreams with them.

 And perhaps this is the best name of all, for these troubled times. Pick a dandelion clock, rediscover your inner child, blow as hard as you can and send dandelion seeds skywards, into the blue. 

 

Cherry-plum, infected with pocket plum disease

I had been hoping for a good cherry-plum harvest this summer - the fruits make excellent jam - but the hedgerow trees that I had my eye on are infected with pocket plum disease, caused by the fungus Taphrina pruni. In the first picture you can see one uninfected developing fruit, green, and then the rest are red, swollen and deformed so that they are flattened, resembling pockets. Soon spores will erupt from their surface.

In previous years I've seen infections on sloes and on bird cherry. This is the first year I've seen a severe infection on cherry-plum.

 

Tawny mining bee

 I encountered this lovely little female tawny mining bee Andrena fulva, provisioning her newly-excavated nest tunnel with pollen, on the Teesdale Way footpath between Egglestone and Meeting of the Waters. The lower three images are of what I think is a male of the same species, photographed in my own garden in County Durham, where tawny mining bees are excellent pollinators of blackcurrants.

Brittle bladder-fern

 Brittle bladder-fern Cystopteris fragilis in a shady, damp retaining wall in Teesdale, North Pennines. A beautiful, delicate fern with brittle frond stalks, typically found in crevices in limestone and mortared walls in the northern dales. Growing with hart’s-tongue fern in the third picture.

Tawny owl

 Ashes limestone quarry at Stanhope in Weardale ceased operations over 80 years ago and has since become a haven for wildlife. The bottom of the quarry is now a lake with a good range of wetland plant species, including mare's tail, reed mace and water mint, and is a breeding site for several dragonfly and damselfly species. The vertical cliff face hosts nesting jackdaws and sometimes its larger cavities ae occupied by less familiar bird species, like this tawny owl that I saw there a couple of weeks ago.