Thursday, July 30, 2020

Broad-leaved helleborine, pollinated by wasps.

We found a population of about 30 broad-leaved helleborines Epipactis helleborine beside the Deerness Valley walk, a disused railway track that has been converted into a pleasant route for walkers and cyclists. 

This is an orchid that thrives on woodland edges, in dappled shade. It's pollinated by common wasps Vespula vulgaris, but this was the first time I have seen the pollinators in action.

The flowers emit a scent that attracts the insects, which have short tongues, so they have to push their head right into the flower to reach a pool of nectar. When they do this the orchid's pollinia, which contain all their pollen, stick to the wasp's face. In the photographs above and below (rather blurred, because the light was poor) you can see a wasp arriving after visiting another plant, carrying the white pollinia on its head, ready to pollinate the flower.

Below, you can see a wasp leaving, taking the sticky pollinia with it, attached to its face.

Click here for a very good YouTube video, by Jean Claessens, of the whole process

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