Tag Archives: honeybee

A thug on the Lamb’s Ears

I walk through our local community garden (The Leechwell Garden) most days in summer just to have a look at the flowers and insects but I know that, if I am there late morning, the sound of children playing will brighten the air.  The older children, sometimes along with mum or dad reliving their youth, will be enjoying the fine new play area with its exciting slide.  The younger ones may be messing about on the watery edge of the stream that passes through the garden but it is the sand pit that really hits the spot.   Children love playing in the sand and I often see several family groups clustered about the sand pit; the only thing that seems to deter the children is heavy rain.  It’s a real tribute to the vision of the garden committee that they created something so popular.

Pair of wool carder bees
Male (left) and female wool-carder bees having a rest. One leaf has been well “carded”.

 

The flowers I come to see are across the other side of the garden and, for the past few weeks, I have been loitering near the old stone wall where there’s a large patch of the plant Lamb’s Ear (Stachys byzantina).  It covers the ground with a jumble of silvery-green, velvety leaves and sends up stout, silvery stems bearing clutches of smaller leaves and understated pink-purple flowers.  It’s a pleasant, restful sort of plant creating an old-style, cottage garden feeling but what goes on around these Lamb’s Ears in midsummer is far from restful.

From the middle of June, a dark, chunky bee can be seen patrolling the patch of silvery-green leaves and I spend more time than I should watching him.  Whereas most bees are gentle creatures keeping themselves to themselves, this one is a bit of a thug, oozing anger and aggression.  He is the male wool-carder bee (Anthidium manicatum), mostly black but with yellow markings along the sides of his abdomen, head and legs, reminiscent of the warpaint worn by native American tribes.  He is about the same length as a honeybee but much broader making him quite imposing as he moves quickly about the patch of Lamb’s Ear.  His movement is distinctive, he hovers then moves rapidly to a new spot, hovers, moves, all the time buzzing noisily.  It feels like he is looking for something.  And that’s exactly what he is doing, looking.  Should he spot another male wool-carder bee or a different insect on his patch, he will chase it away by flying directly at it.  I have seen him attack a bumblebee at least twice his size and knock it to the ground.  But, not only is he aggressive, he is armed; the rear of his abdomen sports five stout spines which he will use to injure or kill the intruding insects and there are reports of male wool-carder bees disabling honeybees who dared to feed from their patch.

All this aggressive energy is directed towards protecting the patch of Lamb’s Ear for himself and his harem, for now and then a female wool-carder bee will appear.  She looks very like the male, only a bit smaller; the wool-carder bee is one of the only species in this country where the male bee is larger than the female.  When the male sees her feeding from the flowers he will pounce and, without any preliminaries, mating will ensue. This is a vigorous but brief activity sometimes causing the flower stem to vibrate before the two disengage and go about their business again.  Unlike most solitary bees, where females mate once, wool-carder females undergo multiple matings so that, after a short time, our male will mate with the same female again and should a different female appear he will attempt to mate with her.  One valiant observer went to the trouble of watching an individual male wool-carder in his garden and reported that the bee mated sixteen times in one day.

This focus on the aggressive behaviour of the male wool-carder bee tends to obscure the fact that it is the female that does all the hard work of nest building and egg laying.  The wool-carder bee is a solitary species so that individual mated females build their nests alone, unlike the more familiar social honeybees and bumblebees.  Nesting occurs in preformed aerial cavities in dead wood, in walls or in hollow stems, including the tubes found in bee hotels.  Once she has identified a suitable site, the female strips or “cards” woolly fibrous material from plant leaves with her mandibles (hence the name wool-carder) and takes it back to her nest to line and plug the cavity (see the pictures below).  Lamb’s Ear leaves are a popular choice for “carding” but Great Mullein or Yarrow can also be used.  If you look carefully at the leaves of these plants you can sometimes see bare areas where she has been actively collecting fibres.  Within the nest, she lays eggs and equips them with a mixture of nectar and pollen.  The eggs develop in the nest where they stay until new bees emerge next summer and the whole cycle begins again.

So, if you have a patch of Lamb’s Ear in your garden take a look, there’s a good chance that wool-carder bees will be using it and you too can be enthralled by their antics.

Male wool carder bee
Male wool-carder bee – look at his spines.

 

Male wool carder bee in flight
Male wool-carder bee in flight

 

Anthidium manicatum mating pair
Wool-carder bee – mating pair

 

Wool carder bee collecting fibres
Female wool-carder bee collecting fibres

 

Wool carder bee gathering fibres together
Leaning back gathering fibres together

 

Wool carder bee flying off with fibres
Female wool-carder bee in flight with ball of fibres

 

Possible female anthidium
Female wool-carder bee

 

Male wool carder bee showing spines
Male wool-carder bee

 

Bumblebee on Lamb's Ear
A brave bumblebee feeding from the lamb’s ears

 

Bumblebees and honeybees share diseases and the outcome is not a good one.

lyme regis february 2014
Bumblebee on Rosemary on Lyme Regis sea front (February 22nd 2014) (photo by Hazel Strange)

I recently read Dave Goulson’s excellent book “A Sting in the Tale” and learnt a lot about bumblebees. Although I was aware of the global trade in honeybees, I hadn’t realised that there was an equivalent trade in bumblebees. Some crops such as tomatoes and peppers require buzz-pollination, the rapid vibration of the flower. Bumblebees do this very well and are now used extensively by commercial growers of tomatoes and other crops. To supply the demand for these useful insects there are at least thirty factories producing bumblebees for shipping all over the world. The numbers are staggering with European factories producing up to a million nests per year. This is big business with huge financial rewards but keeping so many insects together in one place risks the rapid spread of disease unless stringent hygiene precautions are observed. To complicate matters, commercially-reared bumblebees are fed pollen from honeybees so that they are potentially exposed to all the diseases that affect honeybees.

But what about wild bumblebees? What happens when a wild bumblebee forages at a flower that has already been visited by a honeybee? Are the bumblebees exposed to honeybee diseases and what might the consequences be?

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Last week’s Nature magazine carried an article addressing this issue. The team who carried out the work were from Royal Holloway London, Queen’s University Belfast and Exeter University. They showed that some honeybee diseases are indeed a problem for wild bumblebees and could be causing a decline in these wild pollinators. They studied two diseases: the fungal parasite Nosema which weakens honeybee colonies, and Deformed Wing Virus (DWV) which causes abnormalities in the wings and abdomen of infected honeybees as well as severely curtailing their lifespan.

The starting point for the work was to test whether these honeybee diseases could actually infect bumblebees. The researchers inoculated bumblebees (B.terrestris) with DWV or Nosema, and found that bumblebees were indeed susceptible to infection by both diseases. In the case of DWV, infection led to reduced survival of B.terrestris workers. For Nosema, although it could infect bumblebees, this did not reduce their lifespan.

Having established that the two honeybee diseases could infect bumblebees, the researchers examined the incidence of the two diseases. They performed a large scale study on the prevalence of DWV and Nosema in honeybees and bumblebees across 26 sites in Great Britain and the Isle of Man. DWV was found in 36% of honeybees tested and in 11% of bumblebees tested. For many of the infected bumblebees, the virus was active showing that the bumblebees were not simply acting as carriers. Nosema was less prevalent being found in 9% of honeybees and 7% of bumblebees. When the geographical distribution was analysed, there was some evidence for clustering, indicating disease hotspots. Hotspots for DWV were found in the south west and east of Great Britain and for Nosema in the south east. By analysing the distribution of the two diseases they were also able to show that the prevalence of DWV in honeybees influenced the prevalence of DWV in bumblebees, implying local transmission between the two insects. Local transmission was confirmed by analysing the form (nucleotide sequence) of the virus present in the two types of bee collected from the same site.

Honeybees have a high prevalence of DWV, a consequence of infestation of colonies by Varroa mites. The most obvious conclusion from this new work is that honeybee DWV is spreading to wild bumblebees. This probably occurs when the two types of bee forage in the same environment. Because DWV infection of bumblebees reduces their lifespan, the spread of this pathogen could be contributing to the decline in bumblebee numbers.

Both honeybees and bumblebees are important pollinators and need to be maintained. Their loss would have immense financial implications. This research shows that disease control in honeybee populations, for example through the efforts of beekeepers, has important implications for the health of other pollinators as well.

The flowers and the bees

Here, I have been inspired by Emily Heath’s post on her Adventuresinbeeland’s blog.  Emily posted some pictures of bees foraging in Elthorne Park, west London and asked “What flowers are out near you?  Are you seeing plenty of wild bees out and about?”

Accordingly, I have taken some pictures of bees foraging in our south Devon garden and in locations nearby.

One of the favourites of bees all summer has been a patch of Comfrey which grows at the bottom of our garden.  I have the impression that it is favoured by bumblebees and here is a recent picture of a Common Carder Bee (?).

Common Carder Bumblebee on Comfrey

Another long term favourite, but this time apparently preferred by the honey bees (although not exclusively), has been the hardy geranium (probably Wargrave Pink) that occurs in patches in our garden.

Honeybee on Hardy Geranium

The striking orange Montbretia are currently in flower and here is a bumblebee (buff tailed?) foraging.

Bumblebee on Montbretia

Lavender, when it is still in flower, continues to be popular especially with honeybees.

Honeybees and Lavender

I also found bumblees enjoying Bergamot growing in a local community garden.

Bumblebee on Bergamot

The current star-turn, however, is a patch of of Purple-loosestrife growing by our pond.  This is a native wild flower of the UK and grows at the margins of streams, ponds and rivers.

Purple-loosestrife

The plants shown here are about six feet tall and, whenever the weather allows, are covered with honey bees.

Honeybees on Purple-loosestrife

In the UK, preserving the plant is seen as an important part of conserving wetland habitats.  Exactly the opposite view is taken in the US where the plant is viewed as an agressive invader and referred to in the same terms as the triffids in John Wyndham’s novel.  Purple-loosestrife was brought to the US by settlers early in the 19th century.  It rapidly colonised rivers overgrowing native species and destroying wetland habitats.

Let’s finish with an artistic depiction of the plant.  Millais, the 19th century pre-Raphaelite artist, painted a notable picture of Ophelia from Shakespeare’s Hamlet.

Ophelia by Millais

If you look carefully on the right of the picture you can see the tall stems of Purple-loosestrife.  It seems that Millais chose to include these flowers because “long purples” was a traditional name for this plant and because of Shakespeare’s apparent use of this name in describing Ophelia’s death garland:

….. long purples,

That liberal shepherds do give a grosser name,

but our cold maids do dead men’s fingers call them.

Richard Mabey in Flora Britannica suggests that Shakespeare was more likely referring to Early Purple Orchids and the “grosser name” was “dog-stones” meaning “dog’s testicles”.  This was all a bit too strong for Victorian sensibilities so Millais chose the seemlier interpretation.

Another of my bee-related articles can be read here.