Episyrphus balteatus
West Worthing, West Sussex / Island of Madeira / Isle of Lewis
Episyrphus balteatus (male), Worthing, West Sussex, May 2022
[ Wingspan: 7 - 10 millimetres ]

The Marmalade Hoverfly has the twin distinction of being Britain’s most commonly known hoverfly, and the ‘owner’ of a broadly-used English name. It is also remarkable as a hoverfly whose colour is closely dependent upon the temperature at which the larvae developed. If they develop in hot conditions, the adults are almost entirely orange. If they develop during cold conditions, the resulting adults are almost entirely dark, even black. The ones photographed here are mid-way between these two extremes, showing the distinctive double band (thick then thin) on the second and third abdominal segments (the ‘tergites’). This feature is not shared by any other British hoverfly.

This is the species of hoverfly that has been seen arriving in huge numbers, as immigrants from Europe, usually being mistaken for wasps.

Recent research has shown that female Episyrphus balteatus hoverflies have been found flying through the Pyrenees mountains using the sun for navigation.

The individual Episyrphus balteatus hoverfly, photographed on the white Oxeye-daisy below in June 14th 2022, sports an unusual pair of red lines on its abdomen, not often seen in other photographs of this species.

Although these markings appear to be rare (as in not showing up in the majority of photographs of this species available on-line), it is thought that they may be visible signs of internal tubules - not reproductive organs - as these markings have occasionally been seen in both sexes. Anatomical investigation would be required to settle this question, I am told, but not done by me! I make a point of catching these creatures photographically, not with a net.

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