Phasiine expansion update (WIP)

Ectophasia crassipennis (male), Tony Mathews, Torbay 20/7/2023

Back in 2019 we had a mini influx of phasiines which added 2 new species to the British list: Ectophasia crassipennis and Phasia aurigera. Ectophasia was seen 10-12 times that year, spread from Devon in the west to Suffolk in the east; while Phasia aurigera was just seen a few times in Kent and East Sussex. This year has been another good year for phasiines – perhaps caused by the hot, dry weather in 2022, so I thought I’d do a quick update on the key species that seem to be doing particularly well and the recent arrivals.

A map of Ectophasia crassipennis records on iRecord, as of 29/8/2023

There have been lots more reports of Ectophasia from as far west as Cornwall now and the usual scatter of records from Torbay and along the south coast to Suffolk and north to the Norfolk Brecks. I had worried that Phasia aurigera had vanished by it looks like it is hanging on in Kent still because we had a single record this year, logged in iRecord here. It seems to be very close to the first record from 2019.

Since arriving in the Norfolk Brecks a few years ago, Eliozeta pellucens has spread slowly west and we had our first records this year from west Oxfordhsire, which was lovely to see. It’s interesting to note that Clytiomya continua (a very similar species to Eliozeta) has always been on the British list but restricted in range to south Hertfordshire, where it still persists and hasn’t spread.

I’ve written in a previous article about the recent arrival of Cylindromyia bicolor on Rainham Marshes RSPB Nature Reserve. Two independent naturalists have seen it there so it seems to have come in good numbers. Would be interesting to see if that spreads out, as it’s a fairly common, large and very distinctive species from mainland Europe. It is the only Cylindromyia species with a red tipped abdomen.

We’ve also seen a lot of records for Gymnosoma rotundatum plus a few G.nitens, which is still fairly local but I think it is spreading slowly around Essex/London and across the estuary in north Kent. G.rotundatum seems now to have spread to north London and up into Oxfordshire. Cistogaster globosa was recorded from Nottingham this year and has been recorded as far as South Yorkshire and west to Bristol.

We’ve got a lot more of the summer to go yet so I’m looking forward to seeing more records for all these species filtering in – do send in any you see to either iRecord or iNaturalist 🙂