A Tachinid rediscovered: Gonia ornata on the Sefton Coast, April 2021

Gonia ornata, Hightown dunes, Merseyside, April 2021 (Pete Kinsella)

On a visit to Hightown dunes on 10th April 2021, I found the Tachinid fly, Gonia ornata, a species apparently not recorded on the Sefton coast for thirty years. I had already seen Gonia picea (a new species for Sefton, discovered at Hightown in 2020) nearby earlier in the day and upon seeing this latest insect, I initially thought that it was going to be another individual of that species. However, upon closer inspection, it was obvious that this was something else, as this fly had clear reddish coloured panels to the sides of the abdomen. I recalled that another Gonia species, G. ornata, had these markings and that was also on the wing in the Spring (there is another similar species, G. divisa, but that is on the wing later in the year and occurs in southern England). Thankfully, I was able to obtain several photographs of the fly and these enabled the ID to be confirmed later that evening.

According to the NBN Atlas, prior to 2021, there was only one confirmed sighting of G. ornata in Sefton, at Formby Point in 1991. Elsewhere in NW England, there are records from the Solway coast of Cumbria in 2017/18. I informed Phil Smith (PHS) of my sighting and we met at the site on the following day and after some searching saw the insect in the dunes. Remarkably, the next day, 12th April, PHS photographed G. ornata at Wicks Lane, Formby, a few kilometres further up the coast. On 14th April, I visited Ainsdale NNR, further north along the coast from Formby and after a short search, found two G. ornata in the dunes. Clearly something was happening with this species! On subsequent visits to Hightown dunes, up to 21st April, I had several further sightings at various points across the site. It will be interesting to see if this species becomes established here, as G. picea appears to have done for now.

Acknowledgements: Many thanks to Phil Smith, Phil Brighton and Chris Raper for useful comments and information on G. ornata and for confirming the identification.

Gonia ornata, Hightown dunes, April 2021 (Pete Kinsella).