Tag Archives: Eucera longicornis

The long-horned bee in Devon – and its endangered friend

South Devon coast looking towards Prawle Point
The south Devon coast looking towards Prawle Point (June 16th 2017)

 

It’s been a good summer. We’ve had some fine weather and I’ve been able to spend time on a beautiful part of the south Devon coast looking for the long-horned bee (Eucera longicornis).  It’s one of my favourite insects and one of our rarest bees and there is a strong colony on the coast between Prawle Point and Start Point where low, soft-rock cliffs meander around headlands, in and out of rocky coves and along seaweed-covered beaches.  I visited this area several times between May and July but my most interesting day was on June 23rd, just after the summer solstice.

It was breezy and warm but partly cloudy when I arrived at the coast.  The sea was a uniform grey-blue although now and then the sun broke through the cloud, creating shimmering areas of white water. I started by following the coast path eastwards along the cliff top from Prawle Point.  The sea-side of the path was fringed with scrub and rough grass along the cliff edge whereas the landward side was fenced and mostly used for arable farming.  Many kinds of wild flower grew along both sides of the path including a few generous clumps of purple tufted vetch scrambling through the scrub. After about a mile of easy walking, the enclosed path reached a gate giving on to a broad, open area, not farmed for some years, as far as I know.

I was completely unprepared for the view that greeted me after I closed the gate.  Here was a meadow where thousands of the small, dandelion-like flowers of cat’s ear moved with the breezes to create a mobile yellow canopy above the grass.  Lower down were many tiny yellow globes of hop trefoil and bright pink semi-circles of common vetch.  This is a paradise for insects and I saw many red-tailed bumblebee workers moving purposefully about the chrome-yellow flower heads.

But that wasn’t all: the area along the cliff edge was a kaleidoscope of purples, yellows and pinks, mostly flowering legumes such as bush, kidney and tufted vetches, bird’s foot trefoil and meadow vetchling, restharrow and narrow-leaved everlasting pea.   The number and variety of flowers was greater than I can remember from previous years, perhaps the warm spring had suited the legumes.

The range of flowers, especially the legumes is ideal for the long-horned bee.  I had seen one or two males back along the enclosed path and now I saw several more, also nectaring on the curving, purple, tubular florets of tufted vetch.   There is something other-worldly, almost primeval about these insects with their yellow mask-like face, orange-chestnut hair (in fresh insects) and their impressively long antennae, resembling stiff black bootlaces and about the same length as rest of their bodies.  They are particularly striking in flight, antennae held so that the bee can negotiate whatever obstacle it meets;  controlling those antennae must involve some impressive micro-engineering.   There were also females about feeding on lemon yellow pea-like flowers of meadow vetchling.  Chunkier than the males, they have shorter antennae and, on their back legs, generous pollen brushes resembling golden harem pants.

I scrambled down a rough track to the main Eucera nest area, a section of reddish, soft-rock cliff, pock-marked with hundreds of pencil-sized holes.  Behind me the sea soughed rhythmically on nearby rocks and an oystercatcher sang its plangent song. Female Eucera arrived at the nest site bringing pollen and nectar to provision their nests but they were not alone and I saw several other bee species that seemed to be using the nest area.

One species I had hoped to see was the very rare Nomada, and I had nearly given up hope when the bee suddenly appeared; I was so surprised, I nearly fell backwards off the rocks.  Like others of its kind, it is wasp-like, with a yellow and black-banded abdomen and orange legs and antennae. It was the pattern of the bands, six yellow bands on a black body that told me that this was Nomada sexfasciata, the six-banded nomad bee, one of Britain’s rarest bees.  This site on the south Devon coast is the only place where it is found in the UK; it is nationally endangered so it was very exciting to see it.

It moved about the nest area furtively as if trying not to be noticed and after looking in to a few of the holes it moved on. Later that day I had more sightings of the Nomada; whether it was the same bee or several I cannot say.  As a nomad, the bee has no nest of its own but lays its eggs in the nest of another bee, in this case the long-horned bee.  The Nomada eggs develop into larvae and take over the nest, killing the host larvae and eating their pollen store.  It depends for its survival on a strong Eucera colony and this one in south Devon is one of the largest in the UK.

Long-horned bees and their Nomada used to be found widely across the southern part of Britain in the early 20th century.  They favour a range of habitats such as coastal soft rock cliffs, hay meadows and woodland rides for nest sites and require unimproved flowery grassland for feeding, being especially dependent on flowering legumes for their pollen sources.  With agricultural intensification leading to a loss of habitat, especially flowers, these bees have been squeezed out and are now confined to a very few sites.

It’s not difficult to see how they could be supported.  At the south Devon site, all that is required is to ensure a consistent source of flowering legumes along the coast, the soft rock cliffs already provide the nest sites.    I recently met Catherine Mitson who is working with Buglife on a project to support the south Devon colony of Eucera longicornis and Nomada sexfasciata  by increasing the number of flowers.  Catherine is very enthusiastic and I have great hopes now for the survival of both the long-horned bee and its nomad.

Yellow meadow Prawle Devon
The yellow meadow

 

Male long-horned bee on meadow vetchling
Male long-horned bee on meadow vetchling (June 16th 2017)

 

Male long-horned bee
Male long-horned bee on tufted vetch (June 23rd 2017)

 

Female long-horned bee
Female long-horned bee on meadow vetchling (June 23rd 2017)

 

Female long-horned bee by nest
Female long-horned bee at the nest site (June 16th 2017)

 

Female long-horned bee 2
Female long-horned bee with pollen on tufted vetch (July 2nd 2017)

 

Nomada sexfasciata
Nomada sexfasciata by Eucera nests (June 23rd 2017)

 

Nomada sexfasciata 2
Nomada sexfasciata by Eucera nests (June 23rd 2017)

 

Female long-horned bee
Very worn female long-horned bee on tufted vetch (July 23rd 2017)

 

The featured image at the top of this  post is a male long-horned bee on bird’s foot trefoil   (May 23rd 2017)

 

 

Looking for the Long-horned Bee in South Devon

The coast path in this part of South Devon traces the edge of the low crumbly cliffs as they meander around inlets and headlands, keeping the sea at bay. For several miles eastwards beyond Prawle Point, the path is mostly flat so this is easy walking but not without interest. The sea is an ever-changing canvas of colours and seals sometimes swim near the shore. On the landward side of the path a succession of gently sloping arable fields is backed by steeply rising cliffs with rocky outcrops, giving the walker the illusion of being watched from above, if only by birds of prey.

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Looking across Horseley Cove to the coastal fields.  The coast path runs between the coastal fields and the low cliffs. The steeply rising hills with rocky outcrops can be seen behind the fields.

These coastal fields have been cultivated for centuries but for the last twenty years or more, management of the land has been directed towards supporting the nationally rare cirl bunting. This is a pretty songbird that, until the mid 20th century, was found in much of the southern half of the UK. Changes in farming practices, affecting the bird’s food sources and nesting habitat, led to a decline in the cirl bunting population and by 1989 there were only 118 pairs, confined to coastal South Devon. Since then, agri-environmental schemes have been promoted to support the bird. Spring barley has been sown on coastal fields and stubble left in the winter to provide food for these birds. Wide, uncultivated field margins allow tussocky grass to grow and insects to thrive, providing summer food. Nearby hedges are maintained as nesting sites. By 2009 the population had increased to 862 breeding pairs, a conservation success.

Male Cirl Bunting (from the RSPB)

 

The cirl bunting is only one of several rare species found here and many scarce insects find nesting sites along this stretch of the coast. I recently went to look for the long-horned bee (Eucera longicornis), a nationally rare, solitary mining bee that is reported to be found here.

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Just over two weeks ago, I drove to this remote part of South Devon and found my way down the very narrow lane to the National Trust Car Park at Prawle Point. The mid-morning sky was an overcast grey but, with only a light breeze, the air felt warm and humid. The car park is next to a nature reserve and one of the local residents, a lesser whitethroat, sang from a nearby tree as if to welcome me.

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Descending from the car park

A short stroll down hill took me to the coast path and I headed eastwards along the low cliffs. With the lack of sunshine, contrast was low and colours were muted, but there was still much to see. Unusually, I paid scant attention to the sea; I was more interested in the plants growing nearby. The seaward side of the path is marked by a distinct band of vegetation along the cliff edge. Sometimes this is a fringe of low grass with self supporting flowering plants: pinkish-white umbrellas of wild carrot; scrambling legumes including common vetch with its feathery leaves and pink flowers and the tiny white-flowered hairy tare. Further along, growth is more substantial with tall bracken and bushes, sometimes so dense as to obscure the cliff edge. This barrier supports climbing legumes including tufted vetch and, where the blackthorn is well established, provides good nesting for the cirl buntings.

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Commmon Vetch

 

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Hairy Tare

 

The landward side of the path follows the edge of the arable fields and their wide, uncultivated margins. The luxuriously green spring barley fretted in the light wind and, in the field margins, rough grass prospered together with more wild carrot and many leguminous plants including more common vetch. I also saw large mats of kidney vetch sporting a mixture of lemon yellow flowers and feathery- cushioned white seed heads.

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Kidney Vetch

 

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The coast path showing the spring barley, the wide uncultivated field margins and the coastal fringe.

Despite all this apparent fertility and forage, insects were keeping a low profile with the exception of a few small bumblebees. Eventually I came to an area of rich, tall bracken and low bushes growing along the edge of the cliffs. One section of this cliff hedge had been colonised by purple-flowered tufted vetch scrambling through the bracken. Something moving, possibly an insect, caught my eye and I paused to look more carefully. After a few minutes another appeared and I thought I saw the distinctive long antennae of the long-horned bee. I could also see pale brown hairs but the bee was moving about quickly making it difficult to be sure whether this was all just wishful thinking.

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Male long-horned bee on tufted vetch

I waited and an intermittent stream of these insects then passed through, some moving around quickly, some stopping to feed on the purple flowers. They were about the same size as a honeybee and I could see their impossibly long antennae, the very pale front of their heads and the fringe of beige hairs around their thorax. These were definitely male long-horned bees and it was very exciting to see them for the first time. According to Steven Falk, fresh specimens have russet coloured hairs which fade after a few weeks so the bees I saw must have been flying for a while. One of the passers-through had pollen-loaded legs so I assume this was a female but she didn’t stop long enough for me to be sure.

Long-horned bee 7

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This picture shows the pale front of the head

 

By now there was fitful sunshine and I began to be aware of the other sights and sounds around me. Through the curtain of bracken and long grass, the sea was visible, taking on a kaleidoscope of new colours as the weather improved. The urgent metallic sound of cirl buntings echoed around the surrounding hills and coming from below I could hear the plaintive cry of oystercatchers and the gentle soughing of the waves.

 

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The curtain of bracken and long grass

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Long-horned bees used to be found across the southern part of the UK but they have suffered a drastic decline in the latter part of the 20th century. The decline has been due to loss of suitable nest sites and preferred forage.

I visited Prawle Point on June 20th. The two “sunny” pictures (featured image and Coast Path near Horseley Cove ) were taken by Hazel Strange on June 18th.