Tag Archives: red mason bees

A jewel of a bee on a shingle beach

It felt like an unexpected gift, a warm, dry and mostly sunny day after so much dull, wet weather.  I had been feeling very constrained and was determined to get out to enjoy this different day and it looked as though the non-human world felt the same. The wisteria at the front of our house caught the morning sun, wafting its distinctive sweet fragrance on to the air and bees were busily foraging from the greyish-mauve flowers.   Bumblebees, honeybees and two red mason bees (Osmia bicornis males) were among the insects working the blossom.  The Osmia came from one of the nearby bee houses and it was good to see them about after the spell of poor weather.

Hazel had a meeting in Kingsbridge that afternoon, so I dropped her off and took the opportunity to make a quick trip to the coast.  It took me about 20 minutes, passing through several small villages, to reach Torcross and the sea.   The sun shone optimistically as I then began the two and a half mile drive from Torcross along what is known locally as the Slapton Line.  The geography here is very unusual with the road running northwards in a straight line along a narrow bank bordered on both sides by water.  On one side of the road a shingle beach slopes down to the sea and on the inland side a narrow area of rough grass and vegetation separates the road from an extensive lagoon, Slapton Ley.   The situation of the road makes it very vulnerable to storms, high tides and rising sea levels and, in 2018 it had to be closed and rebuilt after damage by Storm Emma.

That day, though, the sea was calm, a deep blue shading to a darker steely blue.  Sunlight sparkled on the surface of the lagoon and generous clumps of thrift decorated the edges of the road as if splashed with pink paint.  When the road turned inland to climb away from the water, I located the car park that gives access to the northern part of Slapton Sands, as it is known locally. 

The beach here is a broad flat plateau of fine, pale brown shingle that eventually slopes down to the sea from a low ridge.  The landward side is backed by densely wooded cliffs giving the beach an enclosed feel and providing some shelter from winds.  This can be an elemental place especially when a westerly gale blows and fierce waves attack the beach. That afternoon, though, there was just a light breeze from the west and spells of sunshine warmed the air.  A few clouds were moving about overhead and as they shifted, mobile pools of light and shade tracked across the shingle.  I paused to stand on the beach for a short time and looked across the water towards Start Point and its lighthouse listening to the sound of the water lapping on the beach and the occasional cry of a passing gull.

The islands of vegetation on the shingle beach showing some red valerian. The wooded cliffs at the back of the beach are just visible and the sea is to the right.

Shingle beaches are rare environments and this one is unlike any other I have encountered, not only for its size but for the special selection of plants that grows here.    The section of beach near the land featured many small islands of vegetation, a green archipelago in a sea of pale shingle.  Often, these islands contained a clump of red valerian, a plant introduced into the UK in the 16th century and now widely naturalised in the west.  Each island also contained a variety of other plants including sea campion, bird’s foot trefoil, forget me not and hawksbeard.  One contained a colony of rosy garlic with its charming pale pink flowers, others supported small shrubs.  The red valerian flowers looked very fresh and many were not yet open.  In a few weeks, though, huge numbers will be in flower casting a distinctive reddish-pink sheen across the beach.

Towards the sea, the green flowery islands petered out leaving a sparsely vegetated zone of shingle populated by plants capable of coping with harsher conditions.  Sea spray and some large waves reach this part of the beach and only specially adapted plants can grow here.  These often have leaves with waxy coatings to prevent water loss and long roots to reach fresh water deep below the shingle.  Sea kale is one of these and imposing clumps of this plant grew towards the shingle ridge.  The clumps were several feet across with fleshy, dark green, cabbage-type leaves tinged with pink, and overlaid with copious sprays of white flowers.  Sea kale is an impressively architectural plant that dominates this part of the beach and perhaps it encourages people to build the beach sculptures with flat stones that I saw nearby.

Rosettes of furry, pale grey-green leaves were also emerging from the shingle in this zone.  These are from yellow-horned poppy, yet to flower.  Later in the year, these plants will light up the beach with their papery, lemon-yellow flowers and enormously long scimitar-shaped seed pods.  Also struggling through the shingle were many long ropes of a plant with fleshy, green, spade-shaped leaves arranged geometrically around a central stem with a slight helical twist.  This is sea spurge another of the plants that frequents these salty, harsh environments.  It has very unusual flowers (see pictures below).

I spent the rest of the time wandering about the beach looking at the flowers, hoping I might see some interesting insects given all the floral resource about.   I concentrated on the bird’s foot trefoil, a bee-favourite that grew well in several of the island clumps.  A few bumblebees were foraging from these bright yellow cushiony flowers and then suddenly another very different bee appeared, feeding from the bird’s foot trefoil, moving purposefully from flower to flower. It was quite small, about two thirds the size of a honeybee and a striking ruby red colour with prominent golden bands of hair around and across its abdomen (see picture at the head of this post and below). 

I had seen several of these insects here two years ago; they are gold-fringed mason bees (Osmia aurulenta) and this one was a female.  Not only are they very beautiful insects with their sparkling, jewel-like colouration but their life cycle sets them apart as they are one of the three UK bee species that nests in empty snail shells.  The female constructs cells within the abandoned snail shell using leaf mastic and provisions each cell with pollen and nectar before laying one egg.  Even more bizarrely, they decorate the outside of the filled shell with more leaf mastic.   Vegetated shingle is one of their favoured habitats and there were empty snail shells scattered sparsely across the beach.  Try as I might, though, I have yet to find one of these insects working on a snail shell!

I visited Slapton Sands on May 19th on a warm dry day but on May 20th, the cold, wet weather returned. After a week, however, something meteorological shifted and, thankfully, summer finally arrived. Many female red mason bees are now busily building nests in the bee houses.

Red valerian in one of the islands of vegetation showing the reddish-pink flowers
Bird’s foot trefoil growing on the shingle
Rosy garlic flowers growing in one of the islands pof vegetation
Sea Kale growing on the harsher part of the shingle beach
Sea spurge showing the rope-like stems and the unusual flowers. The flowers have no petals or sepals but are held in a cup formed from two bracts. The pale green tri-symmetric structure contains one small female flower. The yellow discs are glands that secrete nectar to attract insects and near the glands are several small yellow spherical stamens containing pollen.
A gold-fringed mason bee on bird’s foot trefoil

Lockdown Nature Walks 3

In this third post on Nature Walks during the Lockdown, I want to take you on a very short stroll, only a few steps in fact, into our front garden.  It’s a small garden but it’s south facing and sheltered and it comes to life in the spring, especially on a sunny day.

I stand in the garden and listen.  Today is cooler and breezier than it has been for some days and, across the street, the wind wanders through the developing leaf canopy on the tall sycamore creating a low rushing sound.  A buzzard mews as it circles overhead, a few gulls gossip on the roof tops and a greenfinch wheezes nearby.

But there is one sound I have become accustomed to that I can’t hear today.  This is the continuous low buzz that has been coming from the front hedge on warmer, sunnier days.  The hedge is a Japanese quince (Chaenomeles japonica) and for several weeks has been covered in small fleshy green leaves and bright orange-red, cup-shaped flowers filled with yellow stamens (see picture at the head of this post).  The flame-coloured flowers flare brightly in the spring sunshine, but they tend to be partly buried by green foliage tempering their overall impact.  Once the flowers fade this will be just another green hedge but, in the autumn, when the leaves fall, they reveal attractive pale green fleshy fruits that seem to have appeared from nowhere.  For now, though, the flowers celebrate the spring by being a magnet for all kinds of bee.  Unlike many flowers, there seem to be no preferences and I have seen honeybees, several species of bumblebee and several species of solitary bee, many loaded with yellow pollen; the almost continuous presence of bees working the flowers produces this spring buzz.  I have tried to get pictures of the different bees feeding from the flowers but this has been unusually difficult. It feels as though when the bees see me, they move quickly to flowers deeper in the hedge although I did manage a couple of photos.

A solitary bee resting on the quince leaves. This is probably a mining bee but it is impossible from the photo to determine the species.

 

Another solitary bee, this time feeding from the quince flowers. She is carrying plenty of pollen and when I first saw her I thought she was probably a furrow bee (Lasioglossum sp.).

 

Spring has, however, recently moved up a gear.  There are two small bee houses attached to the front of our house and, a year ago, these were occupied by red mason bees who filled some of the holes, topping them off with reddish mud.  Just over a week ago, two of the mud plugs were broken and out came two red mason bee (Osmia bicornis) males.  There are now at least six and they spend their time flying frantically about the bee houses dancing in the air, sometimes stopping to look in one of the holes, sometimes resting on the wall in the sun and sometimes feeding from nearby flowers.  They are brimming with sexual energy, waiting for females to emerge from the bee houses, desperate to mate and their pent up excitement sometimes leads to mistaken male on male mating attempts.  Male red mason bees are very attractive insects and it’s worth pausing to look.  They are about two thirds the size of a honeybee, and notable for their long antennae, pale facial hair and striking bands of orange hair across the abdomen that sparkle in the sun.

A male red mason bee (Osmia bicornis) resting on the bee house in the sunshine

 

It’s always an exciting time when the mason bees appear and busy themselves around the bee house.  It’s a sign to me that spring has really arrived and summer will follow and I am reassured that nature is still following its plan.

As if to serenade the emergence of the mason bees, the cherry tree near the hedge also burst into flower this week.  I had been watching the tree and thought there would be plenty of blossom and it is now covered in sprays of small white flower buds each clasped by five green sepals.  Many of the buds have opened revealing five pure white petals on each flower, the sepals having bent backwards.  Within the flower there is more to see, a mass of stamens each topped with a yellow anther, also a single thicker pale green pistil.  Our tree is a Morello cherry, a cooking variety and self-fertile but pollination depends on insects to transfer pollen between anther and pistil.  As if to underline this point, as more flowers have opened, I have noticed a stream of insects coming to feed from the flowers including hoverflies, solitary bees and even some of the mason bees from the bee houses.  Some of the solitary bees went systematically from flower to flower so pollination should be fine and, providing the birds are kept at bay, we should enjoy a good crop of fruit in the late summer.

I don’t expect the flowers to last very long so it’s important sometimes to stop, stand back and admire the tree in its spring guise covered with pure white flowers, and remember the poem “Loveliest of Trees” where A E Housman saw his cherry “hung with snow”.

A spray of cherry buds each clasped by green sepals.

 

Mature flowers on the cherry tree showing the five pure white petals. The yellow-tipped stamens and the thicker pale green pistil can be seen more easily if the picture is enlarged by clicking.

 

A hoverfly feeding from the cherry flowers and hopefully pollinating them. This may be a Tapered Drone Fly (Eristalis pertinax).

 

An experimental Bee House

Last year, I watched, fascinated, as Mason Bees (Osmia bicornis) made nests in tubes in a commercially produced Bug House situated in a local community garden, the Leechwell Garden. This Bug House is meant to be educational and so has been placed in a prominent position. This brings with it the risk that it will be subject to some attrition; indeed the removable tubes were tampered with both last summer and this spring and the Bug House was knocked off the wall twice during the winter.

I wanted to build another Bug House for the Leechwell Garden to be put in a less vulnerable place but it proved impossible to find a suitable position. I went ahead anyway and placed the new Bee House at the bottom of my garden which is about 100 metres from the Leechwell Garden (as the bee flies).

Experimental Bee House beginning of season
The Experimental Bee House at the beginning of the season (March 2015). I hope you can see the two vegetable boxes with the sides of the top one insulated with recycled vinyl floor covering, also the protective roof. Two cassettes with tubes are in place in the insulated top box . The garden still looks dormant although a few daffodils are visible.

 

My aim was that this experimental Bee House should be made from recycled materials so that it could be replicated by others at minimal cost. I looked around for suitable materials and one day as I was passing the Totnes shop of Riverford Organic, our local organic grower, I saw some vegetable boxes in the window. These looked ideal to make the body of the Bee House so I contacted them and they kindly gave me two boxes. The boxes were not fully sealed, needing insulation and rain protection, so I went to CarpetRight in Newton Abbot and they kindly gave me some samples of vinyl floor covering. I used these to insulate the sides of the new Bee House and to give it a roof. I found some logs, stones and bricks to provide ballast and stability as well as providing potential homes for insects. I sited the new Bee House so that it caught the early morning sun.

I wanted to provide tubes for the bees to nest in and had hoped to use inexpensive bamboo canes from the garden shop. Although I was able to cut up the canes, I found they were filled with soft material and unusable. I, therefore, had to buy solitary bee tubes from Wildlife World, my only outlay.

Experimental Bee House Cassette
One of the cassettes holding the bee tubes. The tubes are organised in to an old mineral water bottle and secured with a cable -tie. Four of the tubes contained mason bee nests from last year.

 

The tubes were organised in to cassettes. Each cassette was based on an old mineral water bottle cut down below its spout but long enough to protect the tubes. About 20 tubes were placed in to each cassette and these were secured using a cable-tie. I put out two cassettes in March, each containing four tubes with nests from last spring in order to give the new Bee House a start. A third cassette went out on May 28th when I thought the bees needed extra capacity but only two tubes were filled.

Experimental Bee House end of season
The end of season view. In two cassettes most of the tubes have been filled, in one cassette put out later two tubes were filled. Some tubes where the seal was broken have not been refilled.

After I had made the cassettes I read that plastic is a poor choice because it is not breathable but by that time it was too late to change design. Despite this, the new Bee House seemed to have functioned well and many of the tubes were filled by hard-working female bees during spring 2015. This is described in the previous post.

Successes and failures with this year’s Red Mason Bees

As we humans continue our lives and perhaps savour the prospect of settled warm weather and holidays, the busy part of the year is already over for the solitary Red Mason Bee (Osmia bicornis). These important pollinators began their activity in early spring and have now built their nests and laid their eggs.

Last year I was fascinated to watch some of these bees in a Bug House in the local community garden (The Leechwell Garden). This year I kept a closer eye on this colony to try to understand their behaviour. I also built an Experimental Bee House at the bottom of my South Devon garden and watched the bees build nests. [I realise not everyone is interested in constructing new bee houses so I have described this in the next post.]

This week is Pollinator Awareness Week so it is especially important that we think about how to protect and encourage these pollinating insects.

The males emerge and misbehave

male Osmia
Male Red Mason Bee

 

Both Bee houses contained mason bee nests (in removable tubes or in wooden blocks) constructed a year ago. The removable tube nests overwintered in my garden shed and were put out again on March 6; twenty four filled tubes and some empty ones went in the Leechwell Bug House and eight were put in the new Bee House. The wooden block nests stayed out all winter as they are an integral part of the Leechwell Bug House; they may have suffered damage when the Bug House was dislodged from the wall.

Osmia on Bug House
Male Red Mason Bee resting

 

I watched the tubes carefully from mid March and was very pleased to get the first hint that a male had emerged when, on April 16th, I noticed that one of the mud seals had been broken. The day before had been very warm so perhaps that encouraged the bees. Over the next week, I began to see males flying about near the two Bee Houses. Fresh males are very beautiful: about two thirds the size of a honeybee and with long antennae, they have vivid orange abdominal hairs, a fringe of beige hair around the thorax and a very distinctive pale “moustache”. Some look a bit different: they have few abdominal hairs and look rather shiny.

Osmia shiny type
Shiny type

 

Osmia feeding from Forget me Not
Male Red Mason Bee feeding on forget me nots

 

The numbers gradually increased over the next two weeks and on sunny days there would be a cloud of male bees near the Leechwell Bug House (perhaps as many as 30) behaving in a very characteristic way. They would fly about, swinging from side to side rather like a metronome, sometimes stopping to look in to a tube, sometimes flying off to feed on nectar. They would also “bomb” one another, especially another male that had stopped to rest or to warm up. I saw one male try to pull another out of a tube and, once his friend was out, he tried, rather unhelpfully, to mate. The cloud of bees would work themselves in to a frenzy when it was very sunny or when a male/female mating pair was present, perhaps they could they smell other females.

Osmia looking out
It’s too cold for me ……

 

All this activity would stop when the temperature fell to 11oC or lower. The males would retire to the tubes in the Bee House, sometimes two or more in one tube where they would look outwards waiting until the conditions improved. Other bees such as the Hairy Footed Flower Bee continued to forage at this temperature and the disparity may have something to do with size, the larger insect being able to tolerate the lower temperature.

Some females and some mating

mating pair April 28 15 2
Mating pair with mites

 

Mating pair with other bees May 7 15
The stillness of the mating pair and the frenzy of the other males.

 

I didn’t witness any females emerging from their nests but I knew that had happened when I saw mating pairs on April 28th and May 7th in the Leechwell Garden. This was an exciting moment as it was a first for me. I was amused to see the female in the first pair decide to go walkabout; the poor male had no option but to sit there even when dragged in to a hole smaller than comfortable for two bees. My excitement was tempered by noticing many mites on the first mating pair which I suspect is not good news for the bees. The latter mating pair did not have the mites as far as I could tell.

Males near the end

worn out bees

Some of the males continued to patrol the Bee houses up to a month after emerging, ever hopeful of finding a receptive female. By this time they were wizened and black and didn’t look like red mason bees any more apart from their white facial hairs. Perhaps we would also look sickly if we fed on sugar alone. They disappeared altogether by the end of May.

Hard working females

yellow pollen
The first pollen-loaded female.

 

May 12th was another exciting day as I saw chrome yellow pollen on the floor of the Bee House at the bottom of my garden for the first time: I now knew that the females were busy building nests. The females are also distinctive and very beautiful, about the same size as a honeybee and larger than the male with, on their head, two horns which they use for tamping down mud. They lack the pale “moustache” but like the males, their abdomen is clothed in vivid orange hairs when freshly emerged.

Female Osmia bicornis
Female red mason bee. The horns are just about visible.  Her colour has faded and a better view of a fresh female with her orange hair is seen in the mating pictures.

 

I watched the females returning after foraging, buzzing loudly and entering tubes head first. After a short time they reverse out, turn round and back in to the tube. I am not sure what is happening here but I witnessed the behaviour many times. Once this elaborate manoeuvre was complete they flew off for more. I also saw one female building a mud partition. She added mud to the inner surface of the tube and gradually, over several trips to collect mud, built the partition inwards keeping it symmetrical and circular before sealing it off.

Throughout the season, there seemed to be plenty of forage about and no shortage of mud for nest building. For both Bee Houses I saw females continuing to fill tubes in to the third week of June.

Problems

In both locations, the number of females seemed very low, especially as there were plenty of males. Last year most of the tubes and wooden block holes in the Leechwell Bug House were reused by females who cleaned out the mess before re-provisioning them. This year the females did reuse old tubes but seemed to prefer fresh tubes when available. In the Leechwell Bug House I saw only two females but they filled more than twenty tubes. Males emerged from the wooden block nests but none of these was reused. At the bottom of my garden there were at least four females and they filled twenty four tubes. In both locations, the mud seal on some of the tubes remained intact and neither males nor females appeared.

Osmia housekeeping
Housekeeping

 

End of season view
End of season for the tubes in the Leechwell Garden Bug House. Many are filled, a few have not been reused and a few have not been used at all.

 

I don’t know why this year has been less successful but I wonder if the tubes were tampered with at a critical time. I know that some were stolen last summer so I presume that, at that time, many of the tubes were disturbed. I also suspect that the tubes in the Leechwell Garden were tampered with again in March this year. Perhaps this double interference damaged the developing females. The Bug House also fell to the ground twice and perhaps the wooden block nests were damaged. Another possibility is that mated females were produced but decided to go elsewhere.

A third possible explanation would be that the old tubes had been infected with another organism that damaged the developing bees.

I opened up the wooden block nests to see if I could glean any information about these problems. None of these had been refilled this year, whereas last year they were all reused. The wooden blocks were very messy: I could see the individual cells made by the bees but there were no intact dead bees. The nests were filled with a brown dust although within this dust I could see dead larvae. It was also clear that in many cases the mud partitions between cells were still intact. There had clearly been a major problem with these nests and I suspect that they may have been infected. The bees avoided these nests so they seemed to know that something wasn’t right.

I am beginning to think that new tubes should be supplied each year to make life easier for the bees and to avoid build-up of contamination.

Now it’s important to leave this season’s nests so that the eggs can develop and grow in to larvae. I need to wait until late autumn before moving them.

Overview of the year

It’s been another fascinating season of Mason Bee watching and as before I have been enormously impressed by the hard work and ingenuity of these bees, especially the females. The males have only one purpose but they seem to do it well.

Watching these bees is not only a fascinating experience, it also makes you aware of the interconnectedness of the natural world. The bees depend on flowers and the flowers depend on bees. We mess with these relationships at our peril and perhaps we understand our own place in the world by realising this. The highlight of season for me was seeing the chrome yellow pollen for the first time. It signified that everything was working; females had mated and were visiting flowers to continue their species. Fresh yellow pollen has a colour like no other, it seems to glow with the energy of sunlight and signifies the unfolding spring.