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 16^th 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