Long-horned bees along the south Devon coast

A week ago, I went down to the south Devon coast below the village of East Prawle to find the rare long-horned bees that live there.   Their main nest site is located in the low cliffs near Horseley Cove and I scrambled down the steep path to the foot of the cliffs to have a look.  It was a beautiful sunny day and the area was bathed in sunshine while the sea, a deep blue in that day’s light, fussed on the jumble of large boulders that lie just off shore.  The sea was calm when I visited but in the winter these boulders will defend the cliffs from the worst of the storms creating a protected microenvironment. 

Tracts of reddish soft rock peppered with pencil-sized holes were evident across the cliffs and several bees, roughly honeybee-sized, were patrolling the area showing a particular interest in these cavities. They swung in and moved quickly just above the surface sashaying back and forth and from side to side like hyped-up ballroom dancers.  They looked very fresh and were rather lively and It was difficult to discern details but when I focussed my attention on a single insect I could see a pale yellow face, a bright russet thorax and two extra-long antennae, for these were the male long-horned bees (Eucera longicornis) I had come to see.   One landed briefly and I marvelled at his magnificent antennae, each as long as the rest of his body. 

Numbers varied but there were always a few about and sometimes up to six at one time, weaving around one another, creating a loud buzz.  My presence didn’t seem to bother them, some flew around me and another collided with me but they carried on regardless.  They are driven by procreative urges and having emerged from their nest holes in the soft rock within the last week or so, they were now waiting to catch a virgin female as she appeared.  Mating had, though, already begun.  On two or three occasions, a bee flew directly into a hole and didn’t reappear. Photos confirmed that these slightly chunkier bees with golden pollen brushes on their back legs were female Eucera longicornis, already mated and preparing their nests. 

Eucera longicornis is rare and much declined and one of many special insect species found along this stretch of coast, designated a Site of Special Scientific Interest.  The cliff top meadow above the nests was a mosaic of wildflowers and earlier I had found a few male Eucera feeding on bird’s foot trefoil.  The coast path either side of the meadow had, however, been treated with herbicide and strimmed, virtually eliminating wildflowers, seriously degrading this important site.

Male long-horned bee (Eucera longicornis) flying about the nest area

Female Eucera longicornis enetering nest hole

Male long-horned bee (Eucera longicornis) pausing briefly by the nest site on the soft rock cliffs

Male long-horned bee and bird’s foot trefoil

Male long-horned bee on bird’s foot trefoil showing his yellow face

Evidence of herbicide use along coast path (photo taken May 21st)

Evidence of strimming along coast path