Spring Smoothtail (Epistrophe eligans)

Spring Smoothtail (Epistrophe eligans) Wing Length 6.25-9.5mm Flight Apr-Jun peaking in May

Species to spot in April

For some people spring arrives with the coming of the blossom, for others the emergence of daffodils and crocuses, the call of the Chiffchaff or the first bees, but I look for the emergence of the Spring Smoothtail (Epistrophe eligans). It is a common hoverfly strongly associated with the blossom of spring. It also signifies the start of the hoverfly season with more species emerging in the coming weeks and months. It gladdens my heart when I see them.

Its an anthropophilic species, which means it thrives in human modified areas. If you don’t know much about hoverflies this is a good one to start looking for, being easy to find in your garden or just beyond your garden gate. Especially along a hedgerow or woodland edge, sunny and with a tree in full blossom. The more northerly you are in the UK the less likely you are to spot them, especially so in Scotland where they can be localised.

It’s a very distinctive hoverfly with a shiny brassy (coppery-bronze) thorax, triangular spots on tergite 2 (band of abdomen closest to thorax) and a thin narrow yellow band underneath it on tergite 3. The female is a little brighter than the male with more yellowing on the abdomen. I would still check those eyes to ensure gapping, as abdominal markings for this species are variable. 

It’s a univoltine species – which means it completes only one generation per year. The female lays its eggs on the leaves and stems of trees and shrubs, about shoulder height. The larva which are legless resemble little green maggots, often to be found on Elder and Hawthorn where there are plentiful aphids - this is where I often find them. As they mainly hunt for these aphids at night, they often rest in the day under leaves, so worth looking under rather than on a leaf. It takes the larvae roughly 3 weeks to reach maturity, having gone through several moults. They are super pest controllers, especially for orchards and gardens with blossoming trees.

Unlike most other hoverflies which pupate to produce the next generation of adults, these hoverflies go into a long diapause. The larvae drop to the ground where the spend the summer, autumn and winter in the leaf litter. They can be difficult to see as they turn pale brown, blending in with the decaying organic matter, so it’s important not to tidy away leaf litter. Pupation occurs the following spring from within a teardrop-shaped puparium late March and early April. I spot this hoverfly earlier and earlier each year, a species impacted by climate change.

Until recently this Smoothail was referred to in the UK by the common name Spring Epistrophe or Elegant Eligans but the latest two published hoverfly books Hoverflies of Britain and North-West Europe and A Photographic Guide to Flies of Britain & Ireland refer not only to this species, but the group, as Smoothtails. In the UK there are 7 species, including the Broad-banded Smoothtail (E.glossulariae) which is also common but on the wing in late summer. There are 11 species across Europe and 75 worldwide. Epistrophe eligans was classified taxonomically by Harris in 1780.

There is also a variant of the Spring Smoothtail to spot called ‘trifasciata’ which has wide yellow bands on tergite 3 and a thin one on tergite 4 which I believe I captured a few years ago see below. 

Have you seen any Spring Smoothtail this year?

Anyone spotted the variant trifasciata?

Or any its larva feeding on aphids?

Let me know in the comments below if you have……