Nursery web spider

 The rough grassland on the old Brancepeth  colliery site, never grazed or mowed, is perfect habitat for the nursery web spider Pisaura mirabilis. This female had recently enclosed her egg cocoon inside a silken tent woven around grass stems - a nursery where the vulnerable spiderlings can hatch and grow in safety.

Over 250 years ago, the Swedish taxonomist Carl Alexander Clerck gave this species the scientific name Pisaura mirabilis, the marvellous Pisaura. Its fraught courtship ritual has been a source of wonder for arachnologists ever since. Males pacify females, which are notoriously prone to cannibalism, with the gift of a fly wrapped in silk. The larger the fly, the longer it will take to unwrap and eat, extending the opportunity to copulate before her hunger turns to aggression. So, there is a premium on males who are good hunters, though deceitful suitors sometimes wrap and present small twig fragments, risking death mid-copulation when she uncovers the fraudulent offering.

If she does accept his advances she'll eventually produce a ball of eggs wrapped in white silk that she carries in her jaws, slung under her body, until they are almost ready to hatch. The egg cocoon is so large that she is forced to walk around on tip-toe, to keep it clear of the ground.

 These pictures show what happens next - a remarkable example of spider maternal instinct. Her eggs have matured and the grasses have grown tall, so she climbed to the top and bound a few together with silk. Then in the space below she wove a tent, deposited her eggs inside, nibbling through the cocoon so that the spiderlings could hatch and then finally sealed them inside their silken nursery. 

Now, she’ll stand guard until they grow large enough to bite their way out of their nursery and take their first steps into the outside world. In the photographs below you can see her yellow egg cocoon, safe inside the nursery she has woven, with spiderlings beginning to hatch.

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.

Queen wasp mating

 Poor photo (heavily cropped, taken with an old phone in deep shade) but this appears to be a queen wasp mating with drones. They all flew away, still locked together, before I could get a better picture.

Mid-July seems very early for new queens to be leaving a nest - they usually hibernate after mating - but still plenty of summer left for her to start a new nest this year, I suppose.

Two wasp generations in one summer? Are seasonal patterns of insect behaviour confused by changing climate, maybe?

This morning, riverbank footpath, Durham city

Centaury

 Wild flowers have bloomed early and flowered quickly in this year's summer heatwaves. The barley harvest has already begun and grassland in the landscape is parched, the colour of a well-baked digestive biscuit. So I was surprised to find these exquisite little flowers of centaury Centaurium erythraea in full bloom amongst withering grasses on a footpath verge, in a place I've walked many times but had never seen them before.

Centaury is an annual species that seems to thrive in dry locations, including sand dunes. Its seeds germinate in late autumn when water is plentiful, wintering as a rosette of leaves, restarting growth in spring and then sending up a spike of flowers in early summer. If this year's sequence of heatwaves and drought becomes established, maybe this winter-annual growth pattern will be a winning strategy.

Ripe cherries

 Wild cherries Prunus avium have been ripening this week in Weardale. I've tasted quite a lot of wild cherries over the years and most are sour or bitter-tasting, but occasionally I come across a tree with unusually juicy, deep red fruits that make excellent cherry sauce for pouring over ice cream. It looks like a bird has already had a peck at one in the first picture, below. Once they begin to ripen the birds take them very quickly. 

Rooks often eat those that fall under the tree but only hawfinches have beaks that are strong enough to split open the stones. Otherwise the seeds pass unharmed through their gut and are dispersed to become new seedling trees, unless field mice find them. 

When I demolished our old garden shed a few years ago I found a wood mouse's stash of scores of cherry stones from the tree that used to grow in our garden hedge, each with a neat hole nibbled in it, where the rodent had extracted the kernel.

Choke fungus - Epichloe typhina

These strange white sheaths around the stems of grasses are the spore-producing tissue of the fungus known as choke Epichloe typhina. It's present inside the grass all year-round, living as microscopic hyphae within the spaces between cell and benefitting from sugars produced by the host's photosynthesis, but is only visible to the naked eye in summer, when it produces its spores externally around the stem. The white fungal sheath will turn orange-brown when the spores are ripe and ready to be shed, when they are often carried away by small flies.

 The fungal infection tends to prevent the grass culms from flowering, promoting multiple shoot formation instead, but in return the fungus increases its host's drought resistance and produces toxic alkaloids that deter grazing animals, so the relationship between fungus and grass is symbiotic and not simply parasitic.

I found these specimens growing beside a footpath at Wolsingham, Weardale this week.

Two spiders in the bath - only one came out alive

Cellar spiders Pholcus phalangioides look fragile, with those long, slender legs, but they are formidable hunters. This is what happened when a house spider climbed down into our bath, to drink from a dripping tap, and became trapped. The cellar spider climbed down after it, snared it with silk, bit and paralysed it, then wrapped up its prey in a silken shroud.

The cellar spider had little difficulty in climbing out, with its prey slung under its body, then spent the rest of the day clinging to the skirting board, guarding its meal from rival spiders.

These lanky, harmless arachnids need warmth and are confined to human dwellings in Britain. In 1958 the eminent arachnologist W.S. Bristowe, in his book The World of Spiders, described how he zig-zagged across England on his motorcycle, requesting to see hotel rooms on the pretext that he might rent them, so that he could check for the presence of Pholcus and map its distribution. He only found it along a narrow corridor in southern England.

Since then this synanthropic spider has moved north – perhaps in furniture removal lorries, because it seems to have a predilection for living behind settees and under tables – and has even reached the Shetland islands.

Ants tending a herd of aphids

 For the second year in succession we have ants nesting in one of the garden waste recycling bins, which happens to be close to a cardoon plant that's hosting numerous small colonies of black bean aphids. These attract the ants because they secrete sweet, energy rich honeydew, the waste product of the sap they siphon from the cardoon. 

The ants caress the aphids with their antennae, which stimulates the aphids to produce droplets of honeydew that the ants drink and carry back to the nest in their distended abdominal segments.

In the image above and in the final image below you can see a feeding ant's swollen abdomen, rendered almost transparent where the pigmented plates of the abdominal segments have been stretched apart.

Juvenile magpie attempting - and failing - to fend for itself

 Magpies have nested successfully again in a hawthorn near the end of our garden and their fledglings, now well grown, have been harassing their parents relentlessly for food. Lately the youngsters have been showing signs of foraging for themselves and this one mistook the squeaky toy belonging to a neighbour's dog for a real dead animal.

The young bird circled its prey cautiously at first, pecked it a few times to check that it was dead, stood on the toy's head and then pecked and tugged it furiously. 

The attack went on for about ten minutes but, apart from pulling out a few threads, the attacker never managed to reach the stuffing of the soft, cuddly carrion 

It probably would have continued until it broke through the outer covering, but then a parent bird arrived and fed it some real edible food.

Bumblebee nest

 Buff-tailed bumblebees Bombus terrestris are nesting under a moss-covered pile of rocks in the garden. There were field mice living in the rock pile last summer and apparently it's quite common for these bumblebees to nest in their tunnels after the rodents have abandoned them.

The workers are very active and there's a lot of busy pollen collecting going on at the moment, with bees returning with full pollen baskets very few minutes yesterday afternoon.

The pollen they are carrying is orange and most of it is probably coming from this plant, Geum 'Totally Tangerine', which is in full bloom. It's an excellent bumblebee plant for species with short tongues, with open, easily accessible flowers and a long flowering period. The bees collect the pollen by working their way around the central tuft of stamens, buzzing to shake the pollen free and into their fur, they combing it into their pollen baskets.

Green dock leaf beetles

 There are lots of broad-leaved dock Rumex obtusifolius plants around at the moment with foliage that looks like this, resembling green lace.

It's the handiwork of the larvae of the green dock leaf beetle Gastrophysa viridula - turn over a leaf where damage is just beginning and you'll find several on the underside, eating the soft tissue between the leaf veins. When fully fed they burrow down into the soil and pupate, emerging as adult beetles within a couple of weeks.

And here are the rather beautiful adult leaf beetles, mating. The abdomen of the female is so distended with eggs that it displaces her wing cases. She'll lay as many as 1000 eggs and, with a short generation time, the numbers of these insects can rise rapidly as summer progresses.

Flying chimney sweepers

 There were scores of these little chimney sweeper Odezia atrata moths flying in the sunlight in the hay meadow in Durham University Botanic Garden this morning. It seemed as though there had been a recent mass emergence, since they were all in mint condition, with the white tips to their sooty-black wings intact.

Their larvae feed on the flowers of pignut, the white umbellifer growing amongst the hay rattle in the photo below.

The meadow has a sheltered, southerly-facing aspect, perfect for this little day-flying moth that only produces one generation, in early summer, each year.

Butterbur going to seed

It seems like no time at all since the first butterbur flower spikes began to appear along riverbanks in early spring, but now they are ready to shed their seeds. These impressive seed spikes were growing in woodland beside the river Wear at Durham Wildlife Trust's Low Barns nature reserve last week.

There are separate male and female plants of butterbur, which spreads via creeping underground rhizomes. Large areas of England have only male plants, thought to have been transplanted long ago outside of the plant's natural range by beekeepers, because butterbur is a prolific producer of pollen and nectar for honeybees. In Country Durham we have both sexes of the plant so seed set is common, although the female plants only become conspicuous when they elongate and produce these tall seed heads in late spring.
 

Speckled wood butterfly laying eggs

 Speckled wood butterflies have been expanding their range northwards, into County Durham and beyond, for fifteen years now. They've been visiting our garden for about a decade and for the last five years they've been present from early spring until late autumn, so we guessed that they must be breeding here, producing a second summer generation. Last week I found proof.

A female laying her eggs on grass stems, carefully placing them one at a time.

The tiny, glassy pale green eggs provide an excellent excuse for not pulling up the grasses that are infesting the flower borders.

Do ants 'high-five'?

 

Spent a lazy hour sitting in April sunshine watching foraging ants, in constant transit to and from their nest in a big terracotta flower pot. Every time an outgoing ant met an incoming forager their stopped, head-to-head for a moment , to touch antennae, like the pair in the foreground here. Is this the ant-equivalent of a ‘high-five’? I’d like to think so, though it’s most likely colony recognition behaviour, border control, defence against potential invaders.

Stinking hellebore is bumblebee heaven

 Stinking hellebore is an unappealing name for a very bee-friendly plant. It has been the epicentre of bumblebee activity in our garden ever since they first emerged from winter hibernation. The green flowers of Helleborus foetidus are a prolific source of nectar over a prolonged flowering period.

There used to be just one plant in the garden but three years ago I collected all the seed it produced and chucked them on ground where I'd removed a holly hedge in the corner of the garden. There are now about a dozen plants flowering, bearing hundreds of flowers. They don't really stink, they're just a bit pungent on a hot afternoon, but that's a small price to pay for providing such a good food resource for queen bumblebees.

The purple-edged, bell-shaped flowers are unusual because those structures that look like petals are, botanically, sepals that protected the bud during its formative stages. The real petals, inside, are arranged around central whorls of stigmas and pollen-loaded stamens, and are rolled into tubes that are prim-full of nectar.

The flower retains its bell-shape until its pollinated but it's just open enough to allow a large bumblebee to hang underneath and force its way in. Even then, the bee needs to have a long tongue to reach all the nectar. Helleborus foetidus makes its visitors work for their reward. 

If you plant Helleborus foetidus once and let it go to seed it will seed itself around the garden, thanks to the white extension called an elaiosome on the outside of the shiny black seeds.This is very attractive to ants, which carry them away, eat the elaiosome and disperse the seeds, which require a winter of freezing temperatures before they'll germinate.