Easter in the Inny Valley. Purple Toothwort & Oil Beetles

Good Friday in the Inny Valley 

Sitting on the bank of the River Inny having a Good Friday picnic (this was in the carefree days of 2016) we now fast-forward to the same day four years later. It is as if we had snoozed in the sun and then woken up in the middle of a sci fi story. It is Lockdown in spring 2020. Now at least, we have another day of glorious sunshine and the privilege of a garden.

The natural world continues its cycle and my notes about that day four years ago thankfully still apply as if it were now.

I quote “It was sunny and quiet. The river level was quite high and  the water not very clear. It rippled over the rocky bed making a subdued plashing sound. Here and there the shore had patches of stones or sand. In one place there were great white sploshes where a Heron had been standing at the water’s edge. Another little sandy beach had a freshly-made Otter sandcastle, marking its territory.

Just as we sat down, a sulphur yellow male Brimstone dashed past, and then a very sluggish Peacock, which fluttered a few yards and settled with flat wings spread out to bask on a  winter-seared tussock of grass. A Speckled Wood appeared and disappeared in the dappled shade of the riverside trees. Recently I saw  ‘Wood Argus’ in my Dad’s list of butterflies he’d seen around Moretonhampstead in Aug 1928 . I’d never heard of it so I looked it up in the 1916 book on butterflies & moths which he had used, and there sure enough, it was the old name for the Speckled Wood. This earlier name presumably refers to the mythological reference to Argus the Watchful One, deriving from the several ‘eye spots’ in its markings.    

 The golden shining stars of Lesser Celandines looked up at the sun. A pair of Long-tailed tits sent up puffs of pollen as they fed among the Alder Catkins and a pair of Goldcrests fossicked about in the ivy smothering the next tree along the bank. Nuthatches were calling repeatedly in a nearby oak, the fluting notes carrying through the stillness. I thought a bumble bee was passing to and fro, but it was Tony snoring softly beside me.

Moschatel flower

At the foot of the riverside alders were the diminutive greenish flowers of Moschatel. Its five faces gives it the nick-name of Town Hall Clock and its generic name Adoxa means ‘un-showy’. As the plant matures the leaves grow bigger before dying down and disappearing among later lush growth of other plants.

The clear blue sky of earlier was getting smudged by veils of high cloud, and as we walked back along the valley a light south-west breeze picked up."

The Inny is the lowest tributary of significant size to join the Tamar before it becomes tidal. Rising  near Davidstow on the eastern edge of Bodmin Moor  it runs  for  twenty miles through attractive, quiet countryside, with at least nine mills at  intervals before it joins the Tamar at Inny Foot within the extensive Tavistock Woodlands. This is the collective name of several old Oak valley woodlands with big areas of coniferous plantation. It once belonged to the Duke of Bedford who had rides driven through the area to enable his guests to enjoy the woodland which he enhanced with plantings of rhododendrons. At the junction of the two rivers, there was once an ornamental lake called Inny Mere and here, even today there are still botanical relics of this time: the big white-flowered Japanese Heliotrope cousin of our familiar and very invasive Winter Heliotrope (Petasites fragrans), a big stand of Royal Fern and the remains of a Gunnera plant.

Purple Toothwort

In early spring the leafless flowers of Purple Toothwort can be seen growing in clumps on these woodland river banks. It is a parasitic plant, growing mainly on willow and poplar roots. It was introduced to this country as an ornamental oddity in the late 1800s. I have never seen it growing up-stream of these Tavistock Woodlands in either the Inny or the Tamar valleys and my private theory is that it was introduced perhaps accidentally during the Duke of Bedford’s landscaping and planting activities here, and has now spread in the area during floods.

Clumps of Purple Toothwort growing on roots of Willow.

Purple Toothwort closer up.

Oil Beetles

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Violet Oil Beetle

Oil Beetles can be seen now. These rather ungainly flightless beetles crawl around, feeding on flowers or trundling over bare ground The commonest around here are Violet and Black oil Beetles and they can be difficult to differentiate as the blue-violet iridescence can occur on either. Their wings are vestigial, the wing cases or elytra only cover part of the vastly enlarged abdomen. Reaching a size of 2 to 3 centimetres, this beetle gets its name because as a defence it will exude unpleasant caustic oil droplets.

The female lays her eggs in a hole in the turf and the tiny young hatch and crawl into flowers, ambushing certain solitary bees. A bizarre story of parasitism then unfolds. When a bee  alights, these  larval‘ triangulins’  hitch a lift and are taken below ground to the bee’s  nest with its egg and store of pollen  which is then fed upon by the Oil Beetle larvae until they pupates and the following year emerge as adults.

Oil Beetle larvae orTriangulins photoed by our daughter this spring in NW Wales

Triangulin close up

As in the case of so many insects now, Oil Beetles are becoming less common; two of our five native species are now rare and another is believed to be extinct.