Tag Archives: red-tailed bumblebee

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)

 

 

Bees on a spring day

Finally it felt like spring! Two warmer, sunny days in a row and we had to be out on the coast so, on Thursday, we visited Roundham Head Gardens overlooking the sea in Paignton; as we strolled along the cliff paths,  heat radiated back from the south-facing slopes lending a continental feel.  The abundant yellow scorpion vetch gave off a smell rather like gorse and I saw a bumble bee feeding from the buttery flowers.  The sun had brought out many other bees and this is a short post showing some pictures of the species I encountered on a fairly quick walk through the gardens.

Many other flowers were in bloom, but the large banks of rosemary and their disorderly mauve flowers were the most popular haunt of the bees.

honeybee
honeybee

 

B terrestris
Buff-tailed bumblebee (B.terrestris) queen

 

 

B terrestris faded
This one puzzled me, especially with the pollen on her forehead, but Matt Smith helped me to see that she was a faded buff-tailed bumblebee.

 

 

red-tailed bb
A red-tailed bumblebee (Bombus lapidarius)

 

 

Andrena sp
This solitary bee is an Andrena but from this photo it is difficult to determine the species.

 

A flavipes
A female Andrena flavipes (The yellow-legged mining bee)

 

Nomada sp (succincta)
This nomada bee parasitises nests of Andrena. I am not sure about the species but one possibility is N. goodeniana.

 

A plumipes
One of my favourite bees! This is the Male Hairy-Footed Flower Bee (Anthophora plumipes). There were several pale brown males and black females working this newly flowered bank of three-cornered leek in the sunshine. They are rarely still so photography is difficult and this is the best I could do.

 

 

Melecta 1
Melecta albifrons. These large bees parasitise nests of Hairy-Footed Flower Bees (Anthophora plumipes). There are many A. plumipes about currently so there should be plenty of targets for the Melecta.

 

For some fascinating pictures of sleeping Melecta from Stephen Boulton follow this link.

Also, follow this link for an excellent description of Nomada detective work by Megan Shersby.

A sunshine walk, with bees and seals

Start Point is a narrow, rocky peninsula intruding nearly a mile in to the Channel from the South Devon coast. In the past, ships frequently foundered on the rocks and since 1836 a lighthouse has protected the spot. The sinister reputation of the Start Point peninsula is enhanced by its resemblance to the scaly back of a crocodile or sea monster; perhaps in recognition of this it was long ago christened Start after the Anglo-Saxon for tail.

lighthouse at Start Point
The view along the Start Point peninsula towards the lighthouse, looking back from the coast path.

 

Earlier this week, we walked a circular route beginning from the Start Point car park and this post describes some of the highlights. It was the first sunny day for some time and the calm sea across Start Bay was a deep sky blue on a largely wind-free day. What a great pleasure it was to walk in the sunshine, by the sea and in good company!

Our first surprise came as we walked down the road towards the lighthouse. A large bumblebee appeared, as if from nowhere, and after circling a few times to inspect us, landed on Hazel’s hair, buzzing loudly. Hazel kept her cool but, before I could get to the camera, this fine red-tailed queen had flown off. We encountered another red-tailed and several buff-tailed bumblebee queens as we walked and I suppose the warm weather had tempted them out.

The coast path soon deserts the lighthouse road, heading westwards over the spine of the peninsula before dropping down to follow the meandering coastline. There are fine views of the lighthouse and the rocky promontory.

After about half a mile we came to Frenchman’s Rock and its cluster of off-shore rocks; this is one of the places where South Devon’s grey seals congregate. The tide was falling and two impressively large seals alternately hauled out on the rocks and swam about vigorously.

Seal at Peartree Point
One of the seals hauled out on the rocks

 

Between Great Mattiscombe Sands and Lannacombe there is a mile of easy walking along the cliff top. Stonechats skittered about and patches of lesser celandine glowed in the sunshine. I spotted my first solitary bee of the year enjoying the nectar from one of these starry yellow flowers; based on its black and white striped abdomen and hairy back legs this bee was Andrena flavipes, the yellow-legged mining bee.

poss Andrena flavipes
Andrena flavipes on a celandine flower

 

We stopped to eat our sandwiches at Lannacombe where there was a very full stream cascading across the rocks and beach. As it hurried towards the sea, the water created mobile patterns on the sand reflecting the low February sunshine.

Water at Lannacombe
The water at Lannacombe

 

After Lannacombe, the path turns away from the sea up a densely-wooded, steep sided valley where we discovered what might be supporting the bumblebees. Among the bare-latticed trees there were large stands of pussy willow (Salix caprea) covered in oval yellow flowers; from a distance I could see at least one bumblebee enjoying this food source. As I concentrated on the willow trees, the call of a male tawny owl echoed across the valley.

Our route continued up and down on minor roads eventually returning to the coast at Hallsands, a village largely destroyed by storms in 1917 and damaged again earlier this year. There is a prominent block of newly converted apartments; these are mostly second homes and were deserted although I noticed two buff-tailed bumblebee queens inspecting them. Back on the coast path, a mile of gently ascending but very muddy walking returned us to the car park, rewarding us again with ever-changing views across Start Bay towards Slapton and Dartmouth.

lighthouse at Start Point 2
The view from the coast path towards the lighthouse on the return journey

That should have been the end of the excitement but, as we drove away from the car park, we encountered a large number of small black and white birds on the road and nearby fences. This was a flock of thirty or more pied wagtails, flittering about and, of course, wagging.

The featured image is of Start Bay, viewed from the car park, looking towards Slapton and Dartmouth. We walked on February 23rd.

This is walk 18 in “South Devon and Dartmoor Walks” published by Jarrold.

500 dead bumblebees – the chemical blitz of modern farming

In September I wrote about the mysterious death of 500 bumblebees. New information has emerged about this incident so I have rewritten the post:

Earlier this year, Sheila Horne was walking at Hacton Parkway, a public park and conservation area in Havering, East London. April is normally a good time to see insects in their prime so she was very surprised to find many dead and dying bees near the path. She alerted local naturalist, Tony Gunton who identified the insects as bumblebee queens from three species, red-tailed, buff-tailed and common carder. This was not a minor incident, there were as many as 500 bees affected.

Chemical analysis of the dead bees

Natural England was appointed to investigate the insect deaths and samples of dead bees were sent to FERA in York for analysis. The results were released in August and showed that the bees were contaminated with the neonicotinoid insecticide imidacloprid and two fungicides, flusilazole and epoxiconazole. Imidacloprid can be very poisonous to bees and bumblebees are more susceptible to this chemical than honeybees. Imidacloprid is currently subject to a two year partial ban for some agricultural uses in the EU. Neither fungicide on its own is especially toxic to bees although flusilazole was phased out this October because of its high toxicity to fish and because of other potential toxic effects.

A nearby field of oil seed rape as the source of the chemicals?

The chemical analysis raises two questions. Where did the bumblebees pick up these chemicals? Were these chemicals responsible for the bee deaths?

Neither question can be answered definitively but as so many dying bees were found together in one place, it seems likely that the source of the poisoning was close by. Hacton Parkway lies alongside arable farmland and at the time of the poisoning some of the land was planted with flowering oil seed rape, so it is a reasonable conclusion that the bees had been feeding there. Because of the chemical analysis, it was initially assumed that the crop had been planted using seed treated with imidacloprid ahead of the ban and that the imidacloprid had killed the bees. Natural England have recently concluded their investigation and found that in fact the seed used to plant the crop had been treated with another neonicotinoid, thiamethoxam. Neither imidacloprid nor epoxiconazole had been used on the crop and the last spraying with flusilazole was in November 2013. Analysis of the dead bees for thiamethoxam failed to detect any of the chemical but this could have been due to losses before the analysis.

What killed the bees?

So, why did these bees die? Because there are so many unanswered questions we cannot be sure. The dead bees were contaminated with imidacloprid but the oil seed rape crop was not the source. We can only assume that the bees fed elsewhere on imidacloprid-treated crops and were flying with this chemical in their systems. It is known that at typical field concentrations, imidacloprid does not kill bumblebees.

There is also the question of how the bees were exposed to the two fungicides if the oil seed rape had not been sprayed with these chemicals during the flowering season. As with the imidacloprid, we have to assume that the bees were exposed elsewhere. It is possible that the fungicides weakened the bees or made them more susceptible to the neonicotinoids. There is some evidence for such interactions for other insecticide/fungicide pairings.

Because the bees died close to the treated crop, the focus of lethality has to be on the thiamethoxam, now known to have been used on the oil seed rape. Although thiamethoxam is indeed an insecticide, there is evidence from one lab-based study and another field study (albeit lacking controls) that, at field-realistic concentrations, thiamethoxam is not lethal to bumblebees. I find it unlikely, therefore, that thiamethoxam alone killed the bees, providing the farmer followed safety guidelines.

We shall never know what actually happened at Hacton Parkway but my best guess is that these bees were flying with the three chemicals in their system and encountered the thiamethoxam-treated oil seed rape. When they fed from it, they picked up the additional neonicotinoid. Two neonicotinoids, with perhaps synergistic effects of the fungicides, were too much and they died.

The investigation is now closed!

The investigation is now closed and it will be impossible to resolve the many questions raised by this incident, which is a pity. Despite this uncertainty, the results of the chemical analysis stand. These bees died with three chemicals in their bodies: one neonicotinoid and two fungicides. They were also exposed to a second neonicotinoid. This was no laboratory experiment; this reflects what is happening around us when these chemicals are used. Have a look at this report to see more evidence of the widespread use of chemicals in UK farming. Our agricultural practices have led to this chemical blitz and the result is the deaths of important pollinators. How often is this occurring on a lower level but not being noticed or reported?

I should like to thank Tony Gunton (local naturalist) and Helen Duggan (Press Officer, Health and Safety Executive) for sharing information about this incident.

500 dead bumblebees – pesticides leave their deadly trace

Earlier this year, Sheila Horne was walking at Hacton Parkway, a public park and conservation area in Havering, East London. April is normally a good time to see insects in their prime so she was very surprised to find many dead and dying bees near the path. She alerted local naturalist, Tony Gunton who identified the insects as bumblebee queens from three species, red-tailed, buff-tailed and common carder. This was not a minor incident, there were as many as 500 bees affected.

Natural England was appointed to investigate the insect deaths and samples of dead bees were sent to FERA in York for analysis. The results were released a few weeks ago and showed that the bees were contaminated with the neonicotinoid insecticide imidacloprid and two fungicides, flusilazole and epoxiconazole. Imidacloprid is very poisonous to bees with bumblebees being more susceptible to this chemical than honeybees. Imidacloprid is now subject to a two year partial ban for some agricultural uses. Neither fungicide on its own is especially toxic to bees although flusilazole is due to be phased out this October because of its high toxicity to fish and because of other potential toxic effects.

But where did the bumblebees pick up these chemicals? We cannot be sure but as so many dying bees were found together in one place, it seems likely that the source of the poisoning was close by. Hacton Parkway lies alongside arable farmland and at the time of the poisoning some of the land was planted with flowering oil seed rape, so it is a reasonable conclusion that the bees had been feeding there. It is thought that the crop had been sown in autumn 2013 using seed treated with imidacloprid, just ahead of the ban. According to John Rennie of Natural England there had been no spray applications of insecticides or fungicides since the beginning of 2014.

So, why did these bees die? Because there are so many unanswered questions we cannot be sure. The imidacloprid used on the oil seed rape has been blamed by some but I can’t see how this could be a problem if the farmer followed safety guidelines. There is good evidence that exposure to typical agricultural levels of imidacloprid does not kill bumblebees although there is also good evidence for sub-lethal effects on behaviour and reproduction. It is, however, becoming apparent that neonicotinoids such as imidacloprid accumulate in soil so perhaps exposure levels of the dead bees were higher than expected. Soil testing would be informative here.

There is also the question of how the bees were exposed to the two fungicides if no spraying was performed during the flowering season? Does this mean that these chemicals persist for long periods or has there been spraying elsewhere? Perhaps the fungicides weakened the bees or made them more susceptible to the imidacloprid. There is some evidence for such interactions for other insecticide/fungicide pairings.

Although the investigation continues, it may be quite difficult to resolve some of these questions. Despite this uncertainty, the results of the chemical analysis stand. These bees died with three chemicals in their bodies: one insecticide and two fungicides. This was no laboratory experiment; this reflects what is happening around us when these chemicals are used. Our agricultural practices have led to this and the result is the deaths of important pollinators. How often is this occurring on a lower level but not being noticed or reported?

With thanks to Tony Gunton for talking to me about this incident

Bees and Trees seen in Devon

On a sunny day last week, we walked around Salcombe and the nearby coast path. We enjoyed wonderful views over the sea and the coast in this part of Devon. This is not a catalogue of the walk; rather I wanted to highlight two interesting encounters.

red tailed feb 2014
red-tailed bumblebee

Between Salcombe’s North and South Sands beaches we came across a grassy bank in full sunshine. There were many purple flowers, violets and periwinkle, with quite a few bees enjoying the forage and sunshine. One of them was, I think, a beautiful red-tailed bumblebee. (There is a good discussion of identification issues here).

Magnolias at Overbecks
Magnolia campbelli at Overbeck’s

Later on as we descended the coast path from Bolt Tail towards Salcombe, we walked along the boundary wall of the National Trust property of Overbeck’s. This has a beautiful garden built alongside and above the Salcombe estuary. Conditions here are very mild and they can grow a number of tender plants including bananas. Overbeck’s is renowned for its magnolias and over the wall we were able to glimpse the Magnolia campbelli covered in their huge bright pink flowers, looking all the more surprising in the absence of other colour. Originally from the Himalayas, M. campbelli is known for flowering early and for the size of its flowers (at least 20cm across). One of the Overbeck’s Magnolia campbelli was planted in 1901 and a second daughter tree was grown from seed in the 1950s. The early flowering makes the tree vulnerable to frost and in some years the flowers are damaged by a sudden drop in temperature.

The picture doesn’t do justice to the flowers but further down the road we came across two more Magnolia campbelli growing in a private garden.

magnolia at South Sands
Magnolia campbelli in private garden

Although these were not as advanced as those at Overbeck’s itself, they show rather well the mature olive green flower buds and the bright pink flowers. I saw these two trees for the first time three years ago just after they had been frosted. Some petals were still hanging on the tree and some lay on the ground. These thick pink petals the size of pocket handkerchiefs reminded me of the flags used at music festivals such as WOMAD.

WOMAD Festival Reading 2003

With the exception of the WOMAD picture, which comes from Wikipedia, the pictures were taken by Hazel Strange on February 26th 2014.