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.