Marmalade Hoverfly (Episyrphus balteatus)

Marmalade Hoverfly (Episyrphus balteatus) Wing length: 6-10.25mm. Flight: All year.

Species of the week 11th January

If there is one hoverfly everyone probably can spot and maybe even identify it's the Marmalade hoverfly. It is found in most habitats, but especially common in and around the flowers in one’s garden and by far the commonest hoverfly in the country. It is also migratory and has on occasion caused alarm when they invade from the continent in their thousands. They even reached the broadsheets one year causing mass panic to the un-informed, who mistook them for wasps.

https://www.theguardian.com/uk/2004/aug/03/sillyseason.science

They are not only great pollinators but are also, due to volume in numbers, a superb natural pest controller, worthy of attracting to the garden. Encourage them to lay their eggs (white) so that the emerging larva can feast on the aphids in your vegetable patch, and you may get a better crop of cabbages, as they particularly like those aphids (Brevicoryne brassicae). The larvae which are legless, translucent with orange markings, can eat up to 400 aphids during development to adulthood. It would be nice to think that gardeners and farmers could leave these little ‘superheroes’ to resolve these pest problems, rather than with artificial solutions, especially during their peak months July to August.

They are one of the easiest hoverflies to identify as they phenotypically look different to other hoverflies and as such, in the UK, sit in a genus all by themselves. Within Western Europe there are no other Episyrphus species, there are another 22 other species worldwide mainly to be spotted in Africa, Asia or Australia. That doesn’t mean they don’t resemble other hoverflies with those ubiquitous yellow/orange abdominal markings, but as its common name suggests those abdominal markings are marmalade in colour rather than bright yellow typical of other hoverfly species. However, in colder conditions those abdominal markings are often darker, sometimes even black. Honeybee abdominal pigmentation is also influenced by environmental factors, rather than genetics, a term called phenotypic plasticity. As such these darker bees and hoverflies are mainly spotted in the colder months, early spring. Darker flies absorb more solar energy which can be an advantage on cooler days.

Variation seen in Marmalade hoverflies (Episyrphus balteatus) 

It is to date the earliest recorded painting of any hoverfly - painted by Dutch artist Jan Van Huysum 1718, a picture called Still life with Bird's Nest. It is a picture full of flowers, but if you zoom in on the bottom right corner just underneath and to the left of the bird’s nest, you can just about make it out with those distinctive abdominal markings known to Episyrphus balteatus. This hoverfly was painted 58 years before it was scientifically named by Swedish entomologist Charles De Geer in 1776. 

Still life with Bird’s nest - Jan Van Huysum 1718 - right highlighting hoverfly from the painting.

It’s a tiny hoverfly on a large picture so I have done my best to zoom in on it. For a better look may I suggest a visit to the national galleries of Scotland website link below, or if possible a visit the gallery in Edinburgh. Let me know if you have seen it.

https://www.nationalgalleries.org/art-and-artists/128298

Does anybody know of any earlier paintings? Do let me know in the comments below, if you do.

Once you get your eye in with this hoverfly it becomes extremely easy to recognise in the field. The double banded patterns on tergites 3 and 4 of the abdomen, central part going towards the abdominal apex, creates these shapes that resemble a Hercule Poirot styled moustache. These moustaches which I don’t think are particularly obvious in the field, are a signature visual trait within the Syrphidae family. The top band can often be a slightly different shade of orange sometimes silver. Other features to observe are the grey longitudinal stripes on the thorax. Between the thorax and the abdomen is the orange scutellum with a slight greenish centre.

Can you see the moustaches?

I did mention early these hoverflies often migrate. They have been captured migrating through the Alps as they move north in the Spring and have even been found on Oil Rigs resting before migrating further north. Click on this link to discover more. Research has shown that they are able to do this using something called a time-compensated sun compass, which allows them to adjust their heading as the sun moves throughout the day. In Autumn they migrate back south, although some females can overwinter in Ivy, caves and leaf litter and therefore are often seen on warmer days foraging. What’s incredible to know is that these females during the winter are in reproductive diapause and when spring arrives will be able to immediately lay her eyes to start the next generation. I shall be looking out for them in sunny spots over the next few weeks and will let you know if I find any.