Larder beetles

 

 

A larder beetle Dermestes lardarium. This little beetle, about 5mm. long, has a particular liking for laying its eggs on bacon, cooked hams, sausages and fish. It used to be very common in houses in the days before domestic refrigerators were available, but is no longer such a familiar pest.

Those romantic ‘cottage-core’ photographs, of hams and game hanging from wooden beams in country cottage kitchens, belie the constant battle with pest infestations that came with traditional methods of food storage. Neither of my grandparents, who stored their food in a cool larder and their meat in a meat safe, protected from insects by a fine wire mesh, had refrigerators and probably had cause to curse larder beetles.

They also turn up in old wasp nests, feeding on the remains of dead wasp larvae. This one landed on my window ledge and I suspect that it came from an old wasp nest in the loft.

Staphylinid beetle

 This tiny rove (staphylinid) beetle, about 5mm. long, found its way into the house, probably on washing dried on the washing line. But it might have flown in through an open window - the wings are tightly packaged under the wing cases, that look like a miniature back-pack, in the centre of the insect. These small staphylinids are weak fliers, generating enough lift to get airborne, but after that they’re at the mercy of wherever the wind and air currents take them.

Alder leaf beetles

 Low Barns is Durham Wildlife Trust’s largest wetland reserve and the commonest trees there are alders, whose leaves are currently being consumed by a population explosion of these jewel-like, metallic-blue alder leaf beetles Agelastica alni.

Until quite recently, the alder leaf beetle was considered to be a rare species, in danger of extinction in Britain. Then, in 2004 it reappeared in north-west England and over the last twenty years it has become increasingly common in the north east. No one has really identified the reason for its success but it’s common in France, so perhaps it arrived with imported plants from continental Europe. The adult beetle and its larva partially defoliate alders but they recover every spring. The adult beetles fall with the alder foliage in autumn and survive winter in the leaf litter.

Who nibbled these clover leaves?

 

Clover leaflets neatly nibbled around their edges, probably by the clover leaf weevil Hypera postica (?)

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.

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 

The unstoppable advance of harlequin ladybirds

 It's now a 14 years since I first saw a harlequin ladybird in Country Durham, and a decade since I first found one in Teesdale. Yesterday, in precisely the same location, there were hundreds, feeding on ivy nectar. This abundant supply of energy in autumn, coupled with their capacity to remain active in cold weather, must surely be important factors in the phenomenal success of this invasive species. 

Harlequin larvae seem to have an affinity with sycamore, perhaps because of the vast supply of sycamore aphids that they find on the leaves. At this location sycamore and ivy grow together, which might account for the population explosion, with dense ivy also providing a sheltered winter hibernation site.

There now seem to be two dominant morphs in this local population, one black with four large, ragged red spots and the other red with multiple black spots, which is more common. 

 This species is known to be a predator of our native ladybirds and can also transmit a parasite that kills other species. It also feeds extensively on eggs of butterflies and moths. Over the last two decades it has spread rapidly, from south east England to the Scottish border. It originated in central Asia but was introduced elsewhere in misconceived biological control programmes aimed at 'environmentally friendly' aphid control in greenhouse crops. Wherever it has been introduced it has escaped and has had a detrimental effect on native insect populations.

heather moorland in August

 The moorlands of Weardale are a sea of purple heather at the moment, often stretching all the way to the horizon. Billions of tiny, nectar-rich flowers are in bloom, feeding vast numbers of insects, from minute thrips to butterflies.

The flowering of the heather coincides with the breeding season of these heather Colletes bees (Colletes succinctus), below. They lay their eggs in tunnels excavated in the sandy moorland soil, usually on a south facing patch of bare ground, then provision the egg with heather pollen before sealing the chamber. They're solitary bees, unlike the highly organised, social nests of honeybees and bumblebees, but do aggregate their nests in huge colonies. Yesterday we must have walked past many thousands of them, congregating at the entrance to their tunnels and shuttling backwards and forwards to the heather flowers.

The vast expanse of flowers also attracts butterflies. Yesterday we saw red admirals, small coppers, small tortoiseshells and small heaths. The small coppers breed on dense, transient patches of sorrel that grows quickly on the bare soil after a heather burn.

This 'woolly bear' caterpillar (below) is the larva of the northern race of the oak eggar moth Lasiocampa quercus. It spends two years in the larval stage, overwintering as a larva before emerging to feed again, then pupating over a second winter before it finally emerges as a spectacular moth.

And finally, a rove beetle Platydracus stercorarius, with wings tightly folded under those red wing cases

A butterfly haven in an old limestone quarry

This is Ashes quarry, a former limestone quarry near Stanhope in Weardale that is now a wonderful nature reserve. The quarry floor is partially flooded and is a breeding place for dragonflies and damselflies, but this sheltered western end, which is mostly rough grassland and quarry spoil heaps, is always a good spot to look for butterflies.

It was good to see a small colony of wall browns has become established here. This is a butterfly that needs warmth and shelter, so this sun-trap, with its sun-warmed rock, clearly suits it very well.

Wall browns are very skittish insects, never settling for long in one place. This individual alternated between basking on its pile of rocks and feeding on herb robert flowers blooming amongst the stones.

The convenient supply of floral nectar meant that this one was constantly disturbed by rival males that tried to take over its domain. Wall browns are ferociously territorial, so each one of these incursions resulted in an aerial dogfight, as the butterflies spiralled upwards, so close to me that I could hear their wings clashing, before they separated and fluttered back to their respective territories.

Eventually a female arrived and courtsship began, with the pair walking through the grass and the male tapping the female with his antennae. I think the male is the closer of the two in this picture, with some wing edge damage that might have occurred during one of those bruising dogfights with a rival.

Wall brown colonies tend to be small and don't often persist in the same place for long, but this quarry site is sheltered and warm, with plenty of the caterpillar food plants (grasses), so it might last for a few years.

The warm piles of stones in the quarry are also excellent habitat for sun-basking common darter dragonflies ....

..... chirruping field grasshoppers Chorthippus brunneus

..... and this devil's coach-horse Ocypus olens. This beetle (more pics here) isn't often seen out and about in bright sunlight - it's more often seen in twilight.

Beetle with eyes like pearls

I found this ground beetle, which I'm pretty sure is Abax paralellopipedus, in woodland beside Shittlehope burn in Stanhope, Weardale this morning.

It's a common species but what's unusual about this one is its eyes. 

They should be black but these are milky white, like pearls. They don't seem to have the individual facets (ommatidia) that are typical of insect eyes.

I've no idea why this should be but I've had a helpful and rather gruesome suggestion from Dr. Ross Piper

CLICK HERE FOR THE LIKELY CAUSE

The lover of death

I need to thank Amadan on the wonderful iSpot web site for identifying this strange beetle that I found on heathland in Weardale today. 

It was very lively on a warm afternoon, clambering through the heather, raising its wing cases and extending its wings. That broad, flat thorax - like a cloak - is very distinctive.

Here it is at the moment of vertical take-off, when it flew away over the heather.

It's Thanatophilus rugosus, a carrion beetle that lays its eggs on the corpses of dead animals, which then provide sustenance for its developing larvae. Its scientific generic name, Thanatophilus, literally means 'lover of death', in reference to its gruesome breeding habits. In Greek mythology Thanatos was the demon who personified death.

You can find some more examples of carrion beetles by clicking here

Regurgitated beetles and cherry stones

We found this regurgitated pellet, full of cherry stones, near some wild cherry trees in a field beside the river Tees near Egglestone, at the weekend. I'm pretty sure it was produced by a rook, as there is quite a large rookery nearby and I've often seen them feeding in this field.

Regurgitated pellets of indigestible food held in the gizzard are usually associated with raptors and owls but many other birds produce them, including rooks, crows, magpies, gulls, herons and even oystercatchers, which expel pellets of sand grains swallowed with their food onto the seashore.

When I took this pellet home and soaked it in soapy water it fell apart almost immediately, revealing eleven cherry stones, plus ....



..... the remains of at least ten ground beetles. 

Strangely, each of the beetle heads was perfectly intact and snipped off from the rest of the body at exactly the same point. A ground beetle's jaws are quite powerful and I imagine that they would grip the bird's throat as it tried to swallow its prey, so I wonder whether this rook had leaned to detach the heads and incapacitate its victim before swallowing it.

The other debris included fragments of wing case, plus ...

..... lots of legs.

So how did the bird come to be eating cherries and beetles in the same meal? It might be because the ground under the trees was covered in rotting cherries, which might have attracted soft bodied invertebrates like slugs and worms, which might in turn have proved a fatal attraction for the beetles.