Wednesday, July 2, 2014

Bumblebees and the foxglove challenge

Thursday's Guardian Country Diary is about this delightful little lane that leads down from Bulbeck Common to Blanchland. In particular, it's about the roadside verges that are full of wild flowers and were humming with bumblebees.

The sunken lane with high hedges traps the fragrance of wild roses growing on the verges

The tall spires of foxgloves are amongst the most conspicuous wild flowers along the lane and they're particularly attractive to large bumblebees. Visiting the downward-pointing foxglove bells isn't easy for these large insects when they approach in level flight.

First they need to grab the lip of the flower ....

... and then they face an uphill struggle as tyhe climb into the bell, which is slippery. You can often hear the bee buzzing its wings as it struggles in, with the sound amplified by the megaphone-shape of the bell. There must be a lot of wear-and-tear on visiting bees' wings.

The way partially barred by hairs on the petal surface. During the bee's struggle the stigma of the flower - which you can see here at the top of the bell - collects pollen from the visiting bee's back. 

There's not much room inside the tapering bell.

Getting out of the flower isn't easy, either. There's no room to turn around inside so they have to reverse out until they reach the entrance, picking up a smear of pollen on the fur on their back as they near the entrance.

In this picture of a back-lit foxglove flower in a garden you can see the shadows of the two pairs of stamens inside the roof of the bell, where they inevitably make contact with a visiting bee.

Once they reach the entrance most bees seem to exit by just letting go. Notice how the right-hand wing of this individual has been damaged, probably during numerous visits to the confines of the tubular flower in search of nectar.

When bees finally leave most seem to free-falls out into the air-stream before flying off to the next flower.

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