All summer long, and up until a few weeks ago in November, we've had an active European Wasp Vespula germanica (Fr. Guêpe européenne) above our kitchen ceiling. The entrance is just above the back door and the wasps coming and going occasionally freaked people out. But they never caused us any bother. Nobody got stung. They occasionally found their way inside, from whence they would be evicted by me with one of those cheap wasp and spider catching tools.
Hornet Mimic Hover Fly Volucella zonaria larva on our kitchen light switch, 16 mm long unextended.
The other place they found themselves sometimes was trapped in one of the light fittings. I looked forward to the end of the season when the queen would go into hibernation and all the other occupants would die off. I planned at that point to remove the glass on the light and see if there were any interesting species that had been living alongside the wasps. I was particularly hoping for some Volucella spp. They are a type of hover fly that is known to parasitise wasp nests. And I was not disappointed.
The dead insects which had accumulated on the kitchen light fitting.
One day recently we noticed that there was a grub attached to the side of the light switch. Once I'd put my glasses on I could see that it was a Volucella sp larva. So then I needed to identify the species. That was not so easy. Not much is known about them and there aren't that many biodiversity records of them. Based on the information in Graham Rotherhay's guide to hover fly larvae I thought it must be V. pellucens.
Three female Hornet Mimic Hover Flies found in the light fitting. They vary in size between 16 mm long and 22 mm long, which will be due to the available food during their larval stage.
But then I checked the dead insects in the light fitting. Amongst the wasps there were three Hornet Mimic Hover Fly V. zonaria bodies. The larvae of V. pellucens and V. zonaria are very difficult to tell apart. Nicola Garnham, who has done some work with hover fly larvae, said to me on Facebook that she suspected from the start that my grub was V. zonaria, and it seems her experience with these beasties paid off. The live larva has been safely rehomed to a box in the pantry, and I'll try to raise it to an adult fly. Then we will know for sure. But it seems most likely that it is V. zonaria, especially as that is a species I see in the garden much more often than V. pellucens.
Hornet Mimic Hover Fly larva, rehomed.
Hornet Mimic Hover Flies Volucella zonaria (Fr. Volucelle zonée) are big, colourful, distinctive and impressive flies. At up to 25 mm long they are one of the biggest flies in Europe. With their shiny chestnut thoraxes and orangey yellow abdomens striped with black, they are very striking looking insects. The size and overall appearance of this species is reminiscent of a European Hornet Vespa crabro, but their short antennae and plumper shape mean that they are easy to tell apart once you know how.
Adult female Hornet Mimic Hover Fly on Wild Parsnip Pastinaca sativa in our garden.
You can see the adult flies from May to October, buzzing around pretending to be hornets, and mostly, sipping nectar from flowers. Like most hover flies they are good pollinators. They favour a variety of habitats, from beech and oak woods, to scrub and increasingly even urban parks.
Adult male Hornet Mimic Hover Fly in the grounds of the Chateau de Chaumont sur Loire.
The larvae are detritivores (ie the clean up squad) in the nests of bees and wasps, as well as predating the hymenopteran (bees and wasps) larvae.
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