Species Account – Family Syrphidae (Hoverflies)

Summer 2021 saw us take a particular interest in Hoverflies, as it seemed that there were several species hanging about and we didn’t really know much about them, apart from their belonging in the Order Diptera (true flies). It turns out in the UK there are around 280+ species of Hoverfly, of which at the time of writing this only 12 have been recorded in our garden.

One thing we like about hoverflies is that for most genera you can determine the sex of individuals because Male’s have eyes that meet at the top of the head, whereas female eyes are clearly separated. The rule is if the eyes meet then it is certainly male, if they don’t meet it could be male or female depending on the genus, but in most cases its female. For one example where this isn’t the case see Helophilus pendulus below.

A second thing we like about hoverflies is, if you can get one to stand still for a while, you can actually get some rather nice photographs. Indeed they don’t always need to have landed to get a good snap, simply because they are so masterful at hovering dead still in one place.

So what species have we recorded so far?

Starting with the most common and one of the most easy to identify species of them all, the Marmalade Hoverfly (and we thought moths had good names!)

  1. Episyrphus balteatus – Marmalade Hoverfly. One word springs to mind when looking at these guys, neat! A smallish hoverfly but with amazingly defined features. The moustache lines and silver bands give these guys away, nothing else has this pattern. July is the best month to see these, often in good numbers in most places, certainly in Brislington. But we’ve seen them regularly throughout the spring to autumn period.

The larvae feed on aphids, so to gardeners these guys are friend not foe. This is the only member of the genus Episyrphus in the UK. It over winters as an adult and one favoured place to hibernate is under Ivy (3), something our garden has in abundance.

Next up the genus Chrysotoxum, of which we have so far recorded two species. The first we are a little unsure about but we think is Chrysotoxum cautum. The second we are more confident about, Chrysotoxum festivum. The Chrysotoxum are known for having very long, forward pointing antennae as can be seen below…

2) Chrysotoxum cautum. This is considered one of the ‘difficult 5’ (1), five species of Chrysotoxum that are tricky to identify in the field. However it is the only one of these five, according to the distribution maps (1), which our garden is in a hot spot for. Also two of the other five are unfortunately considered either scarce or endangered. Of the remaining two species, which both occur frequently elsewhere in the country, our specimen below best matches the overall species accounts given in (1), however we acknowledge this only as a Most Likely Species (MLS).

3) Chrysotoxum festivum. We were reasonably sure we had identified this one correctly, and thankfully the UK Hoverfly Facebook group (see below) agreed and recorded it as such. The tell tell signs are the black line formed down the side of the abdomen due to the yellow bands not reaching the edge, and legs that are all and all over orange. There is only one very rare species this could be confused with but this is restricted to sites in Hampshire and Dorset (1).

Next up our only member so far of the genus Xanthogramma, X.pedissequum. We chose this species next because like the above two species it is a bit waspy (by the way! hoverflies do not have a sting!), but it cannot really be confused with a Chrysotoxum species as it lacks the long antennae.

4) Xanthogramma pedissequum. This is a Most Likely Species (MLS) but there are only two other known Xanthogramma species in the UK (1). One is X.citrofasciatum, but it’s not our species because citrofasciatum has a much narrower (not triangular) yellow band (see below).

However the third Xanthogramma species is the new kid on the block, being recognised only since 2012. The Facebook UK Hoverfly group had a look at the above photograph and suggested caution in confirming this as pedissequum.

5) Eupeodes corollae. This one is more hoverfly like than the previous 3 waspy types, but its banding looks a bit similar. This species, with the common name Migrant Hoverfly, has again been confirmed by the Facebook group. I think this identification was aided by our specimen being male, as having an angle of 90 degrees or more where the eyes meet (remembering that females never have eyes that meet) at the front edge eliminates E.luniger as a possible alternative, which has an angle noticeably less than 90 degrees.

There are however other Eupeode species this could be, but (1) suggests where the yellow markings meet the edge of the abdomen, if this is 50% of the area or greater then this is likely to be E.corollae (see image above).

A hoverfly of open ground and a bit anthropophilic, found on farmland, parks and gardens, where adults look for umbellifers to feed from (2). Larvae feed on aphids, many associated with legumes and other crops (2).

This is one species that overwinters as a pupae, which is uncommon (2).

6) Meliscaeva auricollis. Another species confirmed by the Facebook group, but this time it’s harder to say why. In the UK there are only two Meliscaeva species (1) and our specimen looks more like auricollis than the second species. However both are widespread and identification is best confirmed by photographs of facial features, so something to get more evidence of next spring / summer. Hopefully we can confirm the presence of both species (1).

A common woodland species that prefers white umbellifers (2). Larvae feed on aphids.

7) Syrphus sp: This is a problem genus according to (1). There are five UK representatives of this genus and to distinguish them from each other requires some skill and close examination of features such as eye hairs and wing microtrichia. So this fella will likely forever remain unknown at the species level, but a different species none the less.

8) Helophilus pendulus. Another species confirmed. However before we go into detail on this species, this is a good example from which to raise the idea of a ‘Tribe’. In this case the genus Helophilus is one of several other genera that make up the Tribe ‘Eristalini’. The genera are gathered together under the banner Tribe (which sits between Family and Genus) because of two main evolutionary and visible characteristics.

Firstly on the adult, a close examination of the wings shows what is known as the R4+5 loop. See below on this enlarged photograph of H.pendulus. The other visible characteristic is found on the larvae. The larvae for this Tribe are aquatic and known as rat tailed larvae on account of a long narrow breathing tube which apparently looks like a rats tail. All representatives of the genera that make up this tribe share these two characteristics.

As for how we know this is Helophilus pendulus. Well there are only 5 species of Helophilus in the UK. Two are either high latitude species or haven’t been recorded for decades. Of the remaining two, H.hybridus and H.trivittatus, because our specimen is a male we can rule out hybridus, as the male of this species lacks the black band shown above and below. We can also rule out trivittatus as it lacks the black central face band found on all other Helophilus species (1).

Another known anthropophilic species (one regularly seen in human environments) but favouring freshwater/wetland habitats (2). With nearby Eastwood Farm containing these habitats in abundance it’s no surprise to see this common species in our garden. It is known to visit gardens some distance from breeding grounds (1). Another species that favours yellow and white flowers (3).

9) Sphaerophoria spp. Another problem genus. To positively ID any of the 10 or more British species requires internal examination of the males, not something we intend to do. Some species are more obvious than others however, such as Sphaerophoria scripta, a species which is widespread but as yet not recorded in the garden. For now the lady below is down to genus level only…

10) Myathropa florea – The Batman Hoverfly. The common name for this common species is very apt. The image on the left below is a specimen recorded in our garden, however the one on the right (taken at Tortworth, South Gloucestershire) better illustrates the origins of this common name and one way to ID this species. However this superhero marking isn’t always obvious.

This species is the only one of this genus in the UK and as stated in the photo above this genus is part of the Eristalini Tribe, having both the distinctive R4+5 loop and rat-tailed larvae (see also H.pendulus above).

Primarily a woodland species, but also requiring standing water in which the larvae develop (see section below on helping hoverflies in our gardens), but apparently they can also use compost heaps (2). Adults enjoy visiting white umbellifers (2) so perhaps enjoys the cow parsley, yarrow and other such species found in abundance at Eastwood Farm.

11) Volucella pellucens – Great Pied Hoverfly. You are unlikely to confuse this with anything else, being almost all black with one large pale yellow/white band.

Typically associated with woodlands, so perhaps our visitor flew over from Eastwood Farm in search of flowers to feed from. Often seen in woodland rides and paths, the males are known to defend a beam of sunlight (1) and investigate from there other visitors of the same species.

The larvae are scavengers/larval predators in wasp (Vespula) nests (2). It seems the brave females of this species can just enter a nest unchallenged by the hosts (1).

12) Platycheirus albimanus. Not all hoverflies are yellow and black, although even within this genus most are. But not this little lady, who’s grey spots and orange legs make her easy to identify.

These guys are recorded as being rather anthropomorphilic, being regularly recorded in gardens amongst low vegetation (2), but also associated with other human influenced habitats such as tracksides and hedgerows. Another aphid feeder on various low growing bushes and shrubs. The adults are apparently keen on white and yellow flowers in particular (3). So worth us keeping an eye on the creeping buttercup patch for this species. This common species can be seen all year round but most numerous in the spring (1) .

Note the following species (were added after the initial article above was drafted….

13) Eristalis tenx – The Drone Fly. Another member of the Eristalini Tribe. As shown below these guys have the clear R4+5 loop. You can identify this species due to the vertical dark (longer) hair stripes on these eyes (1). See below.

As a member of the Eristalini Tribe, this species will have rat-tailed aquatic larvae. This very common species likes organically rich fresh water in which to develop and we often see it around the farm yards we occasionally visit.

14) Syritta pipiens. Another relatively easy species to recognise once you know what to look for. Basically any decent photograph from the side should show the edges of the thorax are obviously grey and the tibia on the hind leg is enlarged. This is the only representative of this family in the UK.

15) Sphaerophoria Scripta: As noted in 9) above, S. scripta is perhaps the one species of Sphaerophoria that can be readily identified as the abdomen is relatively longer than the the wing length, making it protrude from under the wings when at rest. However even with wings outstretched the difference in length is fairly obvious.

So how can we help hoverflies within our gardens and possibly attract more species?

Of the species already recorded there does seem to be a preference for yellow and white flowers, especially umbellifers, but I imagine the hawthorn we intend to plant will be a favourite for many species. With the exception the genus Rhingia, who’s representatives have a proboscis to feed from deep flowers, all other UK species / genera have to feed from shallow flowers, such as buttercup and from our observations California Lilac (of which we are growing another cutting for the top of the garden or perhaps the front of the house) is a particular favourite. However we are considering planting fennel (which we can grow in pots) to add some more yellow flower and perhaps some Astrantias beneath the Harry the Hazel, to give the old boy some colour.

We do already have one or two allium plants which hoverflies love. These are not on our species list yet as we don’t really know what they are or for that matter where they came from. They just turned up one year and have come back ever since.

Another suggestion in (1), which does have a few pages towards the back on gardening for hoverflies, recommends creating a Hoverfly Nest Box. This won’t sound as impressive as a bug hotel, but if it works it works. Basically fill a bucket with twigs and leaves and let it fill with rain water OR attach a plastic bottle to the side of a tree (out of direct sunlight, don’t want to cook anything) and cut a hole in the side, having filled it to this point with sawdust and twigs, then add water and keep it topped up. Perhaps this is something we can add to the rear of the wildlife hotel (see projects page). This should attract lots of Myathropa florea (Batman hoverflies, see above).

What can we do beyond our gardens?

If you find yourself enjoying hoverfly recording, then you may as well make use of the fabulous Facebook UK Hoverflies group. They will not only help identify the species (ideally after you have attempted to yourself), but can record the species for the monitoring programme (they have rules on this but its all very friendly) which helps them better understand species distribution on a national scale and monitor population levels.

The book given in reference (1) below, Stuart Ball and Roger Morris: Britain’s Hoverflies, is one I cannot recommend highly enough. More than enough to get you up and running should you to find you enjoy watching these amazing creatures. The species accounts are there for reference but the book also covers more general information such as life cycles, habitats, hints of capturing hoverflies etc. which are very enjoyable to read.

DC 13/12/2021

(1) Ball, S. and Morris, R. Britain’s Hoverflies: A field guide. 2nd Edtition. Princetown University Press 2015

(2) Speight, M.C.D. (2011) Species accounts of European Syrphidae (Diptera), Glasgow 2011. Syrph the Net, the database of European Syrphidae, vol. 65, 285 pp., Syrph the Net publications, Dublin.

(3) de Buck, N. (1990) Bloembezoek en bestuivingsecologie van Zweefvliegen (Diptera, Syrphidae) in het bijzonder voor België. Doc.Trav. IRSNB, no.60, 1-167.