Hoverfly - Common Dainty (Baccha elongata)

Common Dainty (Baccha elongata) Wing length 4-8.25mm. Flight Apr-Nov

Species of the week – 10th November.

The first thing to notice about these hoverflies is that they look like no other hoverfly. They have this slender body with a wasp waist and hover around plants without visiting any actual flowers, or at least rarely. You might even wonder if they are in fact a hoverfly at all? Well yes, they are, they have the definitive vena spuria, the false unconnected vein, typical of all hoverflies, Syrphidae.

This hoverfly has several different names in literature: Common Dainty, Gossamer, Slender Waisted and the one I really love is the Dutch name ‘Vilegende speld’ which translates as the ‘flying pin’. But for the purposes of this article, I am going to refer to them as Common Dainty, as that is what they are commonly known as in the UK. 

The Common Dainty is the only Baccha species in the UK, a sole representative of its tribe, although there are a further 14 others recognised across the world. They have a resemblance to the much smaller fen flies of the Neoascia genus and Sphengia group, although the latter have thick thighs.

I like to call them the Common Dainty, as they are small, delicate, and often move in a careful way. It’s such a joy when you come across one in the field as they often just flutter in and then no time at all they have fluttered out. They just tease the plants as they hover and slowly manoeuvre through them with such grace, rarely settling long enough to get a photograph.

They often visit gardens as well as being spotted beyond the garden gate, but more often than not they are found at woodland edges where they lay their eggs, particularly amongst bramble and nettle. Here the larva will hatch and feast on ground-layer aphids, often in the shade making them difficult to find. The larva doesn’t look too dissimilar to the white colour form of Common Banded (Syrphus ribesii), but lacking the dark central chevron markings. 

The adult is thin and slender bodied, the elongate abdomen ending in a club like tip, (tergites 2&3 being narrower than 4&5). These wasp mimics have variable yellow markings on tergite 3 and 4. Their long wings can be dark or transparent. The thorax & scutellum black and shiny. They have two generations a year, so most likely spotted spring and autumn but can be recorded most months of the year. They are not known to migrate which might account for this long season. It was spotted in my garden only last week see article W/C 3rd November

Other Notes:

Europe: B.Elongata, perexilis & euryptera.

B.obscureipennis is often recognised as a slightly darker form of elongata with grey dusting absent on the frons.

Asia: B.maculata, bistriatus & laphrieformis.

North America: B.elongata & congnata

Listed on Wikipedia: Baccha - Wikipedia 

B.nana, okadomaei, optata, sachalinica, shirakii, sibirica, where all classified by Violovitsch & euryptera 1976 and strandi by Duda in 1940 

Hopefully in time genetic sequencing of their DNA will determine whether there are 15 Baccha or less.