A close encounter with the hoverfly Brachypalpoides lentus in ancient woodland.
Brachypalpoides lentus is a very handsome, uncommon hoverfly that is found in Ancient Woodland where it is often associated with old beech trees. The larvae live in the decaying heart rot of both live and dead beech trees and on occasions are thought to use oak.
This is an elusive shade-loving insect and occasionally the adults can be found sitting low on the trunks of old beech or on the dappled foliage or vegetation around the trunks . The first indication that B. lentus is about, is a flash of the partially blood red abdomen. On closer inspection, not always possible, for B.
lentus it is often a nervous insect, the femora of the hind legs is enlarged with tufts of white hairs. The only species
B. lentus could be confused with is the common
Xylota segnis, which has been shown in this thread and again is featured here, but that species is smaller with an orange abdomen and partially yellow legs.
B. lentus is one of the species that I hoped to see and photograph in England's New Forest, a famous area for scarce insects with its wealth of heathland and old woodland but I did not find it there. Recently I encountered
B. Lentus sitting on a leaf of grass by a ride (track edge) in Savernake Forest in Wiltshire but before I observed it closer, the hoverfly was gone and I again had a brief glimpse an hour later in the same location as one quickly passed in shade through bramble growing over a fallen beech tree and for an instance it appeared to feed along with the
bombus bees at wild raspberry but soon vanished.
A few days later in the late afternoon, while I was walking back uphill through the forest after an unsuccessful search for
B. lentus along the ride where I had seen it previously. I thought it might be a good idea to look around the bases of the old and dead stumps of beech trees that I had searched earlier in the morning for
B. lentus but then had saw no sign of the hoverfly. Some of the beech trees in Savernake are magnificent and tower over a 100 feet (30.48 m) above the rides. As I now approached a dead black rotting stump of a beech, I saw a
B. lentus female sitting in the deep shade in a hollow at its base, as I moved closer, a Lesser Stag Beetle -
Dorcus parallelipipedus took this opportunity to appear and away went the hoverfly at quite a turn of speed.
I came to a grove of tall old living beech trees and there again at the base of a moss covered beech in deep shade was another
B. lentus but again a movement and it was gone, this was indeed proving a difficult fly to photograph. Searching around the base of another nearby beech I saw a flash of red and a male
B. lentus settled low down on the raised exposed roots, and then to my surprise another male appeared, but this was was quickly grasped by the one already there, both falling to the ground, a vanquished male flying high into the air.
This time the hoverfly took turns resting on the trunk and flying off and returning either to the wood or the vegetation around the tree's base or on the leaves of the tree on a low bough.
Lying horizontal among the many ants and egg- bearing spiders and close to the hoverfly, which at last proved to be a good subject, my attempt at images was at first disappointing, there was no macro depth of a field in such a poor light, what was needed was an external macro flash commander set, quite an expensive item and when attached rather bulky. At one point the
B. Lentus buzzed my face and hovered with that deep red abdomen inches from my person, at last a close encounter of a hopeful kind. In the dappled light of the nearby vegetation I was able at last to get some decent images. Sometimes by just observing the habits of insects you are interested in, you can learn a great deal and that late summers afternoon among the beech trees of that old royal hunting forest will be a memory not to be forgotten.
Brachypalpoides lentus male, Savernake Forest June 2017.
Below the common hoverfly
Xylota segnis, Savernake Forest, May and the Lesser Stag Beetle,
Dorcus parallelipipedus, which turned up just at the wrong moment.