Paul writes: the Great Pied Hoverfly (Volucella pellucens) is pretty easy to identify. It is one of the largest flies in the UK with a body length of 13-17mm and wing length of up to 15mm. The size, combined with the black and white body, a protruding yellow face and a beautiful dark wing patch make it unmistakable. It is generally considered as a fly of woodland rides or margins and can be seen hovering at head height, darting back and forward defending its territory. However it is very common elsewhere and often visits gardens. This one was photographed on my patio, resting on a Phormium leaf.
The adults feed on the nectar and pollen of a large number of plants, so they are great pollinators. I usually see them on bramble bushes or umbellefers, mainly Hogweed. The female lays her eggs in the nests of social wasps, typically Common Wasp (Vespula vulgaris). The larvae then scavenge on the debris that collects there. Adults eventually leave and pupate in soil adjacent to the nest.. They have a long flight season from May through until October and occur throughout the UK, apart from the more northerly Scottish islands.