Mystery Beetle

My thanks to Richard Jones @bugmanjones for identifying this little beetle that was feeding on a bracket fungus growing on a willow, in Grantchester meadows beside the river Cam near Cambridge last week. It's Diaperis boleti "Once exceedingly rare. Scarce, but spreading or increasing? Mostly E.Anglia and SE England", says Richard.

Colour scheme looks like a sexton beetle but too small (only 4-5mm) and no clubs on the tips of the antennae.

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The Bells! The Bells!

The largest and smallest species of Campanula in County Durham are flowering in Weardale now.

This is the giant bellflower Campanula latifolia, which graces old hedgerows and woodland edges, and .....

..... this is harebell Campanula rotundifolia, which is often seen at its best in short, dry grassland where its slender stems tremble in the slightest breeze.

It’s worth taking a close look at harebell flowers because they have a really neat fail-safe method of ensuring that they’re pollinated.

When the flower is still in bud the style, with a closed stigma at its tip, is surrounded by five stamens that begin to shed pollen. As the style - which is hairy on the outside- elongates inside the bud it forces its way through the tube of stamens surrounding it, sweeping the pollen from their surface. So when the flower opens it looks like this, and any insect forcing its way down to the bottom of the harebell bell will pick up pollen from the outside of the style. At this stage the flower is functionally male, dispensing pollen.

 Once the pollen is all gone the tip of the style splits into three lobes that curl back and now the flower has effectively become female, ready to receive pollen on one of those three stigma lobes from a visiting insect. But what if no pollen-laden insects turn up? No problem; those stigma lobes just keep curling back until they pick up any residual pollen that’s still left on the outside of the style, so the flower self-pollinates. 

Harebells are quite easy to grow from seed and if you do raise some you’ll see why their Latin name is Campanula rotundifolia, even though the plant has long, grass-like leaves: the leaves in the seedling rosette are indeed rotund.

The Hole in the Wall Gang

This wren is nesting in a hole in the wall in a garden near Cambridge.

At this time of year it must be at least its second brood, which probably explains why the parent is looking a bit dishevelled and anxious. It seems to be collecting very small food items, including ants.

Bird's nest orchid

Thursday's Guardian Country Diary is about this strange plant, bird's nest orchid Neottia nidus-avis.

I've only found it on three occasions. 

The first was when I was 18, in my final year at secondary school and studying for university entrance examinations. As the only pupil taking botany A level ( now a long-extinct qualification) I was lucky to be taught by Bill Jackson, a teacher who had done an M.Sc. with the noted botanist Herbert Baker. Bill was a good field botanist who gave me a lot of encouragement and suggested that I should do a field project on orchids in Sussex, so I spent many days when I should have been at school  out on the South Downs, looking for these exotic plants. 

On one memorable day I found bird's nest orchid in a beech wood and photographed it. A few months later, when I went for the university interview, I took the pictures with me. My interviewer had never seen the plant and we spent almost the whole time talking about it. Finding that orchid was most probably a significant factor in being offered a place at university. 

I was thirty years before I found the plant again, in a hazel coppice in a wooded valley in Co. Durham. This time it was a pretty miserable specimen, but it was a real delight to see it again. Every year after that we searched the area in July, hoping that it would reappear, without success until a few weeks ago.

I was tipped off that something that sounded very much like bird's nest orchid had been seen there. We searched the original site in the hazel coppice again, but there was no sign of it. Then, when we turned for home, disappointed, my wife spotted this magnificent specimen in an unlikely place ...

....... growing amongst widely spaced hazels, amongst hay meadow species like meadow cranesbill and pignut.

This is an unlikely plant association because bird's nest orchid is usually found in woodland in deep shade, especially in beech woods where there is very little ground flora.

The plant has no chlorophyll, so has no need of sunlight. Its nutrition depends entirely on a fungus called Sebacina that in turn forms a symbiotic, mycorrhizal association with surrounding tree roots. The fungus gets its sugars from the trees and it in turn enhances the tree roots' capacity to absorb minerals from the soil. The orchid contributes nothing to the relationship, merely living off of the fungus.

The flowers produce a vast number of dust-like  seeds but their chances of landing near the essential fungus are slim. After germination the plant takes a decade to reach flowering size and only flowers once before dying, although it is said that its rudimentary root system, which resembles an underground bird nest, can produce further plants in subsequent years. So we'll certainly be going back next year to see if that is the case.

Tiger crane fly

This colourful crane fly, with black and yellow markings, turned up in our garden yesterday.

My thanks to Graham Watkeys of Methyr Tydfil for identifying it as a tiger crane fly Nephrostoma flavipalpis, after I posted a photograph on the wonderful iSpot web site.

The Teesdale Rhino

Thursday's Guardian Country Diary is about this little beetle. 

We have log piles all around the garden, where the remains of trees that have grown here in the past and are slowly rotting away play host to all sorts of insects. In amongst the logs there's holly, hornbean, whitebeam, cherry, walnut, plum, ash and several different conifers. If they had all been left to grow to full size our small garden would have become a dense forest.

My wife found this beetle in one of the log piles and since I couldn't identify it I posted a couple of photographs on the wonderful iSpot web site.

Within a few days it had been identified by Darren Mann, coleopterist at Oxford University Museum of Natural History, as a female rhinoceros beetle, Sinodendron cyclindricum. Unlike the male of the species, she doesn't have a rhinoceros-like horn on her nose but a few days later we found a mate for her in a grove of beech trees in Teesdale. 

At the time we had no idea what we had found because the beetle had been crawling under loose bark and its head was covered in spiders' webs. It looked like another female but when we took it home to clean it up, gently removing its entanglements, it .....

... revealed this magnificent rhino horn, tipped with a brush of ginger hairs.

From this angle that flat, plate-like front to the thorax reminds me of the dinosaur Triceratops.

This beetle is about the length of my thumbnail.

So what does it use that horn for? It can't be feeding, otherwise surely the female would have one too. Apparently they feed on tree sap.

It must be sexual ornament. It would be good to put two males together and see if they use it as some sort of weapon in a contest for females.So that's my next move - to try to find more and see how they interact.

Meanwhile this male has joined the female in the wood pile, where I hope they are breeding.