Tag Archives: honeybees

Perfect poisons for pollinators – available from your local garden centre

We try to make our garden welcoming for bees by growing flowers that provide pollen and nectar throughout the season. We also have some unkempt areas they might want to nest in and we don’t use any pesticides. I enjoy watching the bees foraging on the flowers as they come in to bloom and currently a large cotoneaster bush is full of small bumblebees buzzing loudly as they feed in the sunshine. It’s been very exciting this year to see bumblebees and solitary bees nesting in the dry-stone walls around the garden.

When we need new plants or compost, there is one local garden centre we use. It has a good range of healthy-looking plants and a very nice tearoom! In early spring, it’s also an excellent place to watch one of my favourite bees, the hairy-footed flower bee (Anthophora plumipes), whizzing about in the greenhouses full of flowers. Earlier this year, on a sunny Sunday afternoon in late March, I noticed that these Anthophora had set up nests in the old brick wall of one of the garden centre’s buildings.

Bee 4
A hairy-footed flower bee foraging on plants within the garden centre

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About a year ago, I saw a crowd funding request from the well-known bee-defender and researcher, Dave Goulson from the University of Sussex. He wanted the money to test whether plants sold in garden centres in the UK and labelled as “bee-friendly” actually contained bee-toxic pesticides, applied during production of the plants. I remember being quite shocked to read about this possibility – could I have been buying plants to help the bees that were in fact laced with bee-toxic chemicals?

I wanted to find out more so I got in touch with our favourite garden centre and asked whether they were using neonicotinoid insecticides on their plants. They reassured me that they were not. So far so good. I then asked if their suppliers used neonicotinoids in the compost on the plants they sold. The reply came back “I’m afraid I can’t answer that question without phoning every supplier. Also a few companies we deal with import some of their stock from other European countries. I’m happy to ask my local nurseries when I’m speaking to them.” That’s the last I heard.
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Dave Goulson got his money and went ahead with the analyses. The results of his tests have just been published and they don’t make happy reading;  here is a link to his blog on the topic. He and his colleagues bought 29 pots of flowering plants from well-known garden centres around Brighton (Wyevale, Aldi, B & Q, Homebase). Many were labelled “bee-friendly” and some had the Royal Horticultural Society endorsement “Perfect for Pollinators”.

They analysed a range of pesticides in leaves and pollen from the plants and found that most of the plants contained a cocktail of insecticides and fungicides. In the leaf analysis, only 2 of the 29 plants contained no pesticides. 76% contained one or more insecticide and 38 % contained two or more. 70% of the leaf samples analysed positive for neonicotinoid insecticides, well known for their toxic effects on bees. In the pollen analysis, neonicotinoids were found at levels known to cause harm to bees. So much for “Perfect for Pollinators”.

As a result of his work, B & Q announced that from February 2018 their plants would be neonicotinoid-free. Aldi revealed that they had stopped using neonicotinoids in October 2016, a few months after Goulson’s analyses took place. Neither B & Q nor Aldi  addressed the other chemicals found in the Sussex analysis.

The Horticultural Trades Association issued a statement that I believe is both silly and cynical, basically rubbishing Goulson’s analysis. You can read Dave Goulson’s rebuttal here.
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So, it really is true that when we buy plants to help bees in our gardens from garden centres, we may be unwittingly exposing the bees to harmful chemicals, despite the “bee-friendly” labels. Also, any insect that nips into a garden centre for a feed, especially early in the season when garden centres have an abundance of flowers, may be getting a hit of insecticide at the same time.

So, what do we do if we want to have a bee-friendly garden?

Dave Goulson recommends the following course of action: if you must buy plants, buy from an organic garden centre or, failing that, go to B & Q or Aldi. Better still, grow from seed or swap plants with friends and neighbours.
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One point that has not been discussed so far concerns potential effects on humans of these pesticides found in garden centre plants. Earlier this year, I bought some fruit bushes from the garden centre and these now have a nice crop of plump berries. If these plants have been treated with pesticides, and of course I don’t know if they have, then the fruit will presumably also contain these pesticides. This possibility makes me very angry. I grow fruit in our garden so that we can eat chemical free, fresh, good quality produce. I don’t want to ingest insecticides and fungicides with poorly defined toxic effects on humans.

The featured image shows a hairy-footed fower bee feeding from plants in a lane adjacent to the garden centre

Bees in a landscape

I’ve always loved visiting galleries, discovering what an artist has created, but in the first week of May, the tables were turned.  For the first time, I was on the other side presenting a joint exhibition with my artist wife, Hazel.   We called the exhibition, “Bees in a Landscape”, and it was based around Hazel’s semi-abstract paintings of memorable views from the South West of the UK depicting the local landscape in all its glories.  Alongside the paintings, I showed photographs of some of the bees I have encountered in these same locations.   We hoped that the exhibition would raise awareness of the variety, beauty and importance of these beneficial insects as well as showing how we can all support them.

Poster for Birdwood & P.V
The Exhibition Poster

It was more than a year and a half ago that we agreed to put on the exhibition and throughout 2016 I photographed bees and Hazel worked hard on her paintings.  I didn’t spend hours looking for rare examples, I just photographed the bees that I saw, often in local gardens or when Hazel and I were out walking together by the coast.  It has certainly made me look more carefully at insects and flowers when we go out.

As the week of the exhibition approached there were many things to arrange: had we done enough publicity, did we have enough wine for the Private View, had we sent out all the invitations, would enough people come? Fortunately Hazel has a lot of experience in putting on exhibitions.  When we spoke to people in the run up to the exhibition, we detected a genuine interest in the topic of bees and the landscape which was very reassuring.

P1080627
Hanging the Exhibition finally finished!

The most stressful time was “hanging” the exhibition.  All the paintings and photos were ready but we couldn’t get in to the gallery until 1730, the evening before the exhibition opened on the Sunday.  There were a few distractions, and it took longer than we expected to decide how to place the work around the gallery and to mount it on the walls, and we had to come back on Sunday morning to complete the job.  In the end, we finished with just enough time to nip home to change and be back to welcome guests for the Private View.

Totnes women's choir, Viva
Roz Walker and Totnes Women’s Choir Viva singing at the Private View

The Private View is one of those special artists’ events that goes with an exhibition.   It’s a chance to invite friends, other artists, and people with a special interest to share a glass of wine before the exhibition is open to the public.  Many people came and everyone seemed genuinely interested and impressed by the work.  We were also very fortunate that, during the Private View, Totnes women’s choir Viva, sang for us creating a magical atmosphere with their beautiful harmonies.  Led by Roz Walker, and dressed in yellow and black, they sang songs about bees based on poems by Rudyard Kipling, Carol Ann Duffy, Vita Sackville-West and one based on the Finnish epic poem the Kalevala.   We were so grateful that they gave their time to come and sing for us.

gallery 1
Hazel stewarding in the gallery

The Exhibition was open that afternoon and then daily until the following Saturday.  Hazel and I split the stewarding duties which meant we each did a morning or an afternoon in the gallery.  Totnes is a busy place and the gallery is in the centre of town so up to 100 people came in each day.  We both had many interesting and unexpected conversations with visitors and I was very surprised at the warmth and interest shown by people who came to look at the pictures, both landscapes and bees.  On many occasions, I heard the comment:  ” I didn’t realise how many kinds of bee there were in this country and how beautiful they are!”  Hazel found that her paintings evoked memories for visitors: of childhood picnics, happy holidays and even a honeymoon.  The greetings cards featuring images from the Exhibition were also very popular.

gallery 3
Two of the bee pictures (actual size of each picture is A4)
gallery 7
Hazel’s painting of “Bantham – the promise of summer” (two canvases each measuring 60X50 cm)

On the Tuesday, I took a small group on a Bee Tour of the public gardens dotted around the centre of Totnes.  It wasn’t a very sunny day but we had wide-ranging discussions and were able to see some interesting bees foraging on large patches of comfrey and cerinthe including female Hairy-footed flower bees, early and tree bumblebee workers and a garden bumblebee queen.

Soundart
My debut on Soundart Radio

Our exhibition was featured on Soundart, a local community radio station.  One of the presenters interviewed Hazel in the gallery and I went to the studio to talk about bees.  This was an interesting experience, if not altogether satisfactory.  After Hazel’s interview had been played, the presenters asked me about the exhibition and about bees which was fine.  When we got on to neonicotinoids, however, the discussion was hijacked by one presenter.  He challenged the possibility of obtaining “evidence” in scientific investigations of complex systems like bees and after his intervention, the bee discussion petered out which was a shame as there were many other aspects we could have covered.

Hazel and I were extremely pleased with the exhibition.  Many people came to look and we had some fascinating conversations.  Several people made special journeys to visit and talk to us.  People went away knowing more about bees.  What more could you we have asked for!?

For more about Hazel’s paintings click here.  The featured image at the top of this post  is Hazel’s painting “Seal Bay (Brixham from Churston Cove)”.

Birdwood House Gallery  web site can be viewed here

One sunny day does not make a Spring

The sun greets the spring

And the blossom the bee,

The grass the blea hill

And the leaf the bare tree

From “Love and Memory” by John Clare

 

The signs have been there for a while.  Birds singing as though someone told them it’s time to turn up the volume.  Grassy banks dotted with starry yellow celandine flowers.  A green haze of fresh leaves slowly creeping over previously bare branches.  If only the weather would play fair it might be spring.

So, after many days of damp and grey, the sun shone, the air was warm and it was as though a transformation had taken place.  It was also Friday Market Day and, as people wandered between the stalls, they smiled at one another and remarked on the weather.  Two busking fiddlers played pleasing harmonies in the Market Square and, outside the Italian Café, it was not quite Tuscan weather but the beautiful people laughed and smiled in the Devon sunshine.

I wandered down to the Leechwell Garden where, soon after I arrived, my attention was grabbed by a low but insistent buzzing.  On an extensive stand of rosemary growing against one of the old brick walls I saw a real sign of spring. It was a chunky bee covered in rich brown hairs but with a pale nose.  Moving quickly and purposefully among the slate-blue flowers, it collected nectar, buzzing as it went.  This was a male Hairy Footed Flower Bee (Anthophora plumipes), my first one of the year and seeing it lifted my spirits.

Elsewhere in town, I looked at a huge willow (Salix caprea) that has been cleverly pollarded and trained over a wall where its many slender stems drop like water over a precipice.  The tree has been covered in immature, grey “pussy willow” catkins and, recently, these have been mutating into bright pollen-loaded male catkins. Last Friday in the sunshine the tree was very impressive: a mass of yellow flower heads, unruly brushes made from the long stamens, alive with honeybees and a few bumble bees and small flies.  The whole tree buzzed as the sun’s energy was transformed into sound.

When the bumblebees saw me, they flew off in disgust.  The honeybees, however, were drunk on pollen and nectar and either didn’t see me or didn’t care.    Many of them already carried large chunks of orange-yellow pollen to take back to the hive but when they encountered a new flower head they wallowed in it, they almost swam in the stamens.  If they could have expressed pleasure this would have been the occasion.

Later, a light mist crept over the hills to the east, gradually enveloping the town and shutting out the sun.

A plumipes
Hairy-footed flower bee on rosemary

 

willow
The willow waterfall

 

honeybee 2
Honeybee on willow catkin

 

honeybee 1
Honeybee with pollen on willow catkin

 

B hypnorum
Tree bumblebee (Bombus hypnorum) on willow catkin

Liquid Energy – ivy bees by the sea in South Devon

Here is an account of a visit I made to Paignton about eight weeks ago, seaching for ivy bees.

Goodrington Sands
Goodrington Sands viewed from Roundham Head

 

Ice cream and chips, not together of course, but that’s what people are eating. The sun is shining, the sea an intense blue, the air gently warm and sun loungers have been dragged unexpectedly out of pastel-coloured beach huts. Couples stroll along the promenade arm in arm and one or two children shriek with delight as they run in and out of the waves washing over the long sandy beach. This is Goodrington Sands near Paignton in south Devon and it’s the end of September.

At one end of the beach, the ground rises steeply to Roundham Head, a cliff-lined, grass-topped promontory that interrupts the otherwise smooth sweep of Torbay. The south-facing side of the headland is home to the Cliff Gardens with its terraced flower beds, zigzag paths and mild microclimate supporting many tender sub-tropical plants. A colony of winter bumblebees also flourishes here, nurtured by the almost year round supply of pollen and nectar.

The flat, grassy surface of the promontory eventually gives way to residential streets but before suburbia takes over completely, there is a transitional region, a mosaic of green rectangular spaces and tall, red-brick walls. Nowadays, the area is popular with dog walkers but, in one wall, there is an intriguing, curved-top gateway, hinting at older usages. These walls, now mostly covered with ivy, are the remnants of the kitchen gardens of a nearby Victorian villa.

About a year ago, I discovered these old walls covered in full-flowering ivy with many ivy bees taking advantage of their preferred food. The ivy bee (Colletes hederae) is the last solitary bee to emerge each year and is very distinctive with its yellow and black-striped abdomen and chestnut-haired thorax. I looked for the nest area but, although I found a few small nest aggregations, I was unable to find anywhere large enough to support the number of bees I had seen.

Today, I park in a street bordering the old kitchen garden. Ivy cascades over the wall by the car, its many pale green flower heads scenting the air with their sickly-sweet smell. Insects move about the ivy constantly, flying to and fro, ignoring me to the extent that we sometimes collide. I see hoverflies, wasps, one or two bumblebees and honey bees, and hundreds of ivy bees. The male ivy bees fly about edgily, sometimes stopping to feed, sometimes pausing on a leaf to preen and rest. The females, noticeably larger than the males, carry chunks of chrome yellow pollen on their back legs and abdominal hairs but continue feeding. Sometimes a hopeful male disturbs them, attempting to mate, but they show no interest in their new suitors. Movement is constant, there is an insistent low buzz and this liquid energy steps up in the sunshine. The same liquid energy abounds wherever the ivy is in flower on these old walls. There is a lot of ivy here and that means many ivy bees.

But where are the nests? Last year I found one small nest area in some exposed red soil along the cliff-side path descending from Roundham Head to Goodrington so that’s where I begin today. Sure enough there are still holes in the cliff face together with crumbly soil suggesting active nests. Around these holes there are hundreds of ivy bee males performing what my friend Susan Taylor has christened the “sun dance”. They fly about incessantly, swinging from side to side, occasionally stopping to look into one of the holes but emerging unsuccessfully. It’s an impressive sight along a two metre stretch but what is lacking are any females and anyway it doesn’t feel like a big enough area to account for all the bees on the ivy so I decide to walk down to Goodrington to look at the sea.

As I stand by the beach, I see someone walking down another steep path from Roundham Head. I hadn’t noticed this paved path before: it runs parallel to the cliff-side path but about three metres inland and is partly hidden behind a low hedge. I decide to take a look. The path is bordered on one side by a low bank covered in short, rough grass and hundreds of ivy bee males fly about, skimming the surface, “sun dancing”. When I get closer, I see that the red soil in the bank is peppered with many holes and crumbly soil is spilling out showing that the bank contains active nests.

The males here seem particularly edgy, they constantly investigate the burrows, presumably looking for females and sometimes they even try to mate with one another, not a clever move. On several occasions I notice the males suddenly congregating to form a rough ball. Other males soon join the melee rather like rugby players in a ruck. Somewhere in the middle there must be a female who has just emerged from one of the burrows. The males are trying frantically to mate with her but only one will be successful and I see one copulating couple fly off together, still attached.

There is also a slow but steady stream of females returning to the nest area loaded with yellow pollen. They have come to deposit food in their burrow for their larvae, but finding their nest looks a bit hit and miss. Some approach the area and fly around for a short time before landing and making their way on foot. Others seem to crash land and then pull themselves together after a short rest. The males show no interest in these already-mated females.

The aggregation covers an area about ten metres by half a metre and there must be hundreds of nests. This is a large, very active, nest site and looks big enough to support a huge number of ivy bees. I can’t say whether there are other nest aggregations in the area but this one goes some way to explaining the large number of ivy bees seen at Roundham Head.

I am completely absorbed watching these creatures go about their lives; it’s like being allowed through a door into another world. But then I look up and see, no more than 20 metres below me, an ice cream kiosk with people enjoying their Devon Farmhouse ice cream. Dogs dash along the hard sand splashing in the water. A steam train struggles up the bank hauling vintage chocolate and cream coaches towards Kingswear.

Roundham Court
One of the old walls and the Victorian Villa overlooking Torbay.

 

Red brick wall plus archway
An intriguing, curved-top gateway covered with ivy.

 

Male ivy bee
A male ivy bee

 

Red soil cliff bank Paignton
Some of the “sun dancing” males by the cliff nests. Some are flying, some are investigating the holes.

 

Soil bank above Goodrington
The grassy bank by the path descending from Roundham Head to Goodrington, with the ice cream kiosk by the beach.

 

Red soil in bank
Crumbly red soil and nests in the grassy bank

 

Mating ball of ivy bees
Male ivy bees forming a mating ball, somewhere in the middle is a female.

 

Mating pair ivy bees
Ivy bee mating pair

 

Female returning to nest
Female ivy bee returning to her nest loaded with pollen

An autumn sunshine walk in South Devon – Salcombe to Gara Rock

East Portlemouth Ferry
The ferry arrives at East Portlemouth from Salcombe

 

Steep steps descend from a narrow passageway off Salcombe’s Fore Street.   At water level there is a stone jetty, the Ferry Pier, and above and to the right the Ferry Inn enjoys almost perfect views across the estuary.   A clinker-built motor boat, with the skipper standing up, is already making its way across the water to pick up the few waiting passengers.  Once we are all safely on board, he backs out and turns before heading across the estuary to East Portlemouth; it’s a calm day so this is an easy crossing.   The view from the boat always impresses me, low in the water, a cormorant’s perspective.  Looking towards the mouth of the estuary, the sea is a dark blue but, in the light breeze, ripples caught in the low sunshine cast a dancing light across the water.

The journey takes only a few minutes but it’s transformative.   Salcombe is all cafes and posh clothing shops but across the water we find peaceful long beaches with fine sand.  The tide is very low so we follow the strandline, leaving a record of our footsteps in the soft sand.  Beachside houses cast long shadows in the low sunshine but, where the sun reaches the beach, it creates pale blues and greens in the seawater, shallow over golden sand, and I imagine the Mediterranean.

Eventually, we reach Mill Bay, a football pitch-sized expanse of undulating, pale sand stretching from the sea to the coast road.  Very popular for family holidays in summer, today it is all but deserted.  On one side of the beach, the low tide has exposed a long, green, seaweed-covered slipway with prominent metal rails and stone teeth.  This was built in 1943 by the US navy to support landing craft during the Normandy landings.  It’s hard to imagine the beaches and the estuary filled with ships awaiting the assault on occupied France.

The rear of the beach is fringed with sand dunes bound together with scrubby grass.  One exposed vertical face is peppered with holes, burrows for insects, and several black and yellow striped wasps are moving about the nest area in a proprietorial manner.  Longer and sleeker than the better known common wasp, these are field digger wasps, solitary insects that dig tunnels in the sand and provision them with dead flies as food for their larvae.  A large buff-tailed bumblebee queen is scrabbling in the sand wall as if she is trying to burrow.  She looks in good condition but behaves as if something is wrong.

The path leaves the beach to head gently upwards through coastal woodland in the direction of the estuary mouth.  The autumn leaf-strewn track meanders through the woods with tantalising views of beaches below.  In today’s light, the colours of the sand and water glimpsed through the trees look more southern European than south Devon.  We emerge from woodland cover into brilliant sunshine and spectacular but slightly hazy views across the mouth of the estuary to the vast green headland of Bolt Head and the sandy beach at South Sands with its boutique hotels.  A red, yellow and blue boat passes by purposefully; it may look like a toy, but it is the Ferry that links South Sands with Salcombe town.

The path turns gradually eastwards seemingly cut into the hillside so that we walk with the land falling away to the sea below us and, on the landward side, rising steeply to rocky outcrops.  There is much bracken in evidence, already showing the effects of autumn; bright sparks of yellow gorse shoot upwards.  We pass a single spike of mullein, a few yellow toadflax and clumps of sheep’s bit with their unruly mops of blue petals.  Several stonechats entertain us, fluttering up and down, tail flicking, chatting.

The sea is calm today. From this vantage point, it is a deep blue but where it meets the rocky coastline, the surface shatters into bright fragments in the sunshine.  I scan the coastal waters for seals but get a surprise when I see what looks like a person standing on a rock just above the sea.  A closer look reveals a large cormorant, sunning itself.   Further away, sailing boats take advantage of the good weather and a fishing boat moors close enough for us to read its name through our binoculars.

Eventually, ahead of us we see a curious, white-painted, cylindrical hut, topped with a thatched roof and perched high above the path upon one of the rocky outcrops.  Far below the hut is a secluded stretch of sandy beach and in the distance lies another headland, Gammon Head.  The thatched hut is the former coastguard lookout at Gara Rock and we leave the coast path to head up to investigate.   Behind the lookout there is a new resort/hotel/apartment complex with people sitting in the sunshine enjoying a drink.  A row of coastguard cottages was built here in the 19th century and converted into a popular hotel early in the 20th century.  Laurence Olivier, John Betjeman and Margaret Rutherford are said to have stayed here, not necessarily at the same time.  The old building was knocked down in the last ten years and rebuilt as the new complex.

The old coastguard lookout has glorious views across the sea and coast and it is surrounded by huge banks of ivy.  Much of the ivy is in full flower, filling the air with its distinctive sickly-sweet smell.  Perhaps it is something to do with the light today but the flower heads on these clumps of ivy appear as almost perfect globes.  Multiple pale green lollipops extend from the centre of each flower head in perfect symmetry, like pins in a pin cushion.  Each lollipop is decorated with a frieze of pale yellow-headed stamens, creating, from a distance, a sunny halo around the green globe.  The ivy flowers attract many insects including more field digger wasps but it is the ivy bees that I am looking for and I am not disappointed.  Many of the elegant yellow and black striped-females move quickly about the flowers together with a few hopeful males.  The females are carrying large amounts of bright yellow pollen but still feeding.

We drag ourselves away from this extraordinary spot and head back down the inland valley to Mill Bay following an ancient, slightly sunken green lane with farmland either side.  This is a green tunnel with muted light, formed by overhanging trees including a long stretch of very old lime trees with dark, gnarled bark and multiple branching trunks.  When we reach Mill Bay, we take the coast road back to the jetty.  Many of the houses here are closed up; more than 40% of the houses in the Salcombe area are second homes.  The chimney of one of these homes is swarming with bees, probably honeybees.  The owner will be in for a shock when they next visit!

For a map and further information on this walk click here.

 

Mill Bay
Mill Bay

 

US Navy slipway, Mill Bay
The old US Navy slipway

 

 

Field Digger wasp
Field digger wasp (Mellinus arvensis)

 

South Sands Ferry
South Sands Ferry

 

Coast Path
The coast path and view across to Bolt Head

 

Sheep's Bit
Sheep’s Bit

 

Coastguard lookout Gara Rock
Coastguard lookout at Gara Rock

 

Inspecting the ivy
Inspecting the ivy at Gara Rock

 

Ivy with ivy bee
Female ivy bee (Colletes hederae) with ivy

 

View from Gara Rock lookout
View from the lookout

 

 

Ancient limes
Ancient Lime Trees

 

Bees in the chimney
Bees in the chimney

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.

Bees and neonicotinoids – another twist in the tale.

To the agrochemical companies and to many farmers they are essential tools ensuring efficient crop production. To environmentalists and to many bee scientists they are dangerous chemicals contributing to declining bee populations. I am talking, of course, about the neonicotinoid insecticides widely used in this country to control insect pests.

Last week two papers were published on-line in the journal Nature emphasising the dangers posed by these chemicals.

One paper, from a team at Newcastle University, investigated whether honeybees and bumblebees showed any preference (positive or negative) for food containing neonicotinoids; there had been suggestions that bees might avoid neonicotinoid-treated crops in the field. The new lab-based work showed that, when offered a choice, bees preferred to eat sucrose solution (nectar) containing neonicotinoids (imidacloprid or thiamethoxam) rather than control sucrose solution. If this occurs in the field then bees may forage preferentially on crops containing chemicals toxic to their health and inadvertently bring back these toxins to their nests.

The second paper, from scientists at Lund University in Sweden, showed that the neonicotinoid clothianidin, when used in the field, damaged wild bee (bumblebee and solitary bee) populations but was without effect on honeybees. I want to focus on this paper as it is the first controlled study of the effects of a neonicotinoid on honeybees, bumblebees and solitary bees under field conditions. Let’s start by looking at the background.

Three years is a long time in science

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Back in 2012, two studies were published showing that neonicotinoids, even when they didn’t kill bees, could affect bee behaviour in a way that impaired survival of honeybee and bumblebee colonies. The findings showed that these chemicals could contribute to a decline in the numbers of bees and other pollinators. These observations had a big effect on policy and indirectly contributed to the current partial ban on the use of three neonicotinoids in Europe.

One of the papers was from Dave Goulson’s lab, then at Stirling, and found that even at the low doses typically encountered on treated crops in the field, neonicotinoids substantially reduced the number of queens produced by bumblebee colonies, so impairing survival. In Goulson’s study, bumblebees were treated with neonicotinoids in the lab before being allowed to fly freely. This is called a semi-field design and some have suggested that the findings cannot be extrapolated to the real world. The levels of neonicotinoids have also been criticised although these were very carefully thought through.

There was considerable media interest in this work, nicely described in Goulson’s latest book (A Buzz in the Meadow) and the UK Food and Environment Agency (FERA) labs in York hastily set up a preliminary field trial to examine the problem. During the spring and summer of 2012 they studied three fields of oil seed rape, one treated with the neonicotinoid, imidacloprid, another treated with the neonicotinoid, clothianidin and a third untreated field to act as a control. Bumblebee (Bombus terrestris) nests were placed by each field and the occupants were left to fly freely and build their colonies. Extensive analyses were performed including colony growth, the pollen collected by the bees and pesticide residues detected in pollen and nectar.

Superficially this sounds like a rigorous study (free flying bees, compare neonicotinoid-treated with control, plenty of analyses and so on) and it should have given an indication of the effect of neonicotinoids under real-world field conditions. The success of the trial depended on the bees foraging on the crop near their nests so there should have been clothianidin-exposed colonies, imidacloprid-exposed colonies and neonicotinoid-free controls. Unfortunately the bees had other ideas; they largely ignored the flowering oil seed rape by their nests, foraging further away and returning with pollen from crops treated with another neonicotinoid, thiamethoxam. This completely negated the original design so that, in my view, no valid conclusions can be drawn from the study, despite official pronouncements.

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The new Swedish study

The FERA work was a valiant but flawed attempt to study the effects of neonicotinoids on bumblebees under field conditions and it was clear that a properly conceived field trial was required. The ambitious new study from Lund University mostly fills that void.

The Lund team selected 16 landscapes surrounding spring-sown oil seed rape fields in different parts of southern Sweden in 2013. The landscapes were divided in to 8 pairs on the basis of the nature of the surrounding countryside and for each pair one was sown with seed treated with the neonicotinoid, clothianidin and the other was sown without neonicotinoid, to act as a control. All seed also contained a fungicide. The neonicotinoid-treated seed also contained a pyrethroid to protect plant roots but there was no evidence that the bees came in to contact with this chemical.

Honeybee hives, bumblebee (Bombus terrestris) colonies and solitary bee (Osmia bicornis) cocoons were placed by each field during the flowering season and their progress was followed. Additionally, the numbers of free flying wild bees (bumblebee and solitary bee) were assessed at each field during the flowering season. Pollen brought back by bees was analysed for flower type and for pesticide residues. The study was large enough to allow statistical analyses to be performed so that valid conclusions could be drawn although the design was unable to detect effects smaller than 20%.

Unlike the FERA study, bees did forage on the oil seed rape adjacent to their colony based on pollen analysis, although this was not an exclusive choice. Bees near treated fields brought back pollen and nectar containing clothianidin whereas those near untreated fields did not. The study design seemed to have been successful and the results were clear:

1. Honeybee hives behaved similarly by treated and untreated fields; there was no effect of the pesticide on colony strength. This is good news for honeybees and for beekeepers and agrees with a 2014 field study from Canada also using clothianidin.

2. Bumblebee colony growth and reproduction were reduced near treated fields. This agrees with earlier semi-field studies so that it is now difficult to avoid the conclusion that agricultural use of neonicotinoids has damaging effects on bumblebees.

3. Whereas solitary bees placed by untreated fields emerged from cocoons and built new nests, this did not occur for cocoons situated near treated fields, possibly because of navigational problems caused by insecticide exposure.

4. The number of free-flying wild bees was reduced by about 50% at the treated fields.

The implications of the new Swedish study

Honeybees were not affected by foraging from a neonicotinoid-treated crop whereas wild bees (bumblebees and solitary bees) suffered reductions in numbers and reproductive ability. Wild bees are, therefore, more sensitive to neonicotinoids than honeybees. This may be because, as James Cresswell at Exeter has shown, honeybees break down neonicotinoids more quickly than bumblebees so that honeybees experience lower doses.

The effect of the neonicotinoid on wild bees is an important result for several reasons. Wild bees are important pollinators, contributing more than half of the “pollination service” required for crops. Crop yield and quality will suffer if these insects are lost so we need to look after them and that may need to include rethinking use of pesticides.

The differential sensitivity of bee types to neonicotinoids shows that environmental risk assessment of new and existing insecticides, typically performed in short term lethal studies on honeybees, is inadequate to determine long term effects on different bee types in the field.

These new data will add to the pressure to extend the European moratorium on the use of three neonicotinoids as seed dressings after the initial two year period ends in December. There is, however, concern that if neonicotinoids are not available then farmers will use older insecticides that may be more dangerous for bees. Perhaps farmers should rethink their use of pesticides and return to a “treat when required” policy rather than using neonicotinoids prophylactically.

When the three neonicotinoids were temporarily banned in 2013, farmers claimed that the yields of crops would be drastically reduced. It is interesting that in the first season when crops were grown from untreated seed in the EU, the yields actually increased. Perhaps we should rethink the use of chemicals more generally in modern farming.