During summer 2020, I regularly visited an area of coarse grassland in the shelter of planted trees at Ravenmeols Local Nature Reserve near Formby. This supported plenty of flowering umbellifers that attracted a wide range of Diptera and Hymenoptera. On 25th July, I photographed a fairly large, unfamiliar tachinid on Wild Parsnip Pastinaca sativa at SD 2833 0558. Chris Raper, a national authority on the family, identified it as Linnaemya picta, a parasitoid of various noctuid caterpillars. L. picta has a mainly southern distribution in Britain, iRecord showing the northernmost sightings up to 2019 being in South Yorkshire and near Buxton in Derbyshire.
Bentley & Raper (2010) reported the first modern record of L. picta in 2009 at Denge Wood, Kent. Initially, the specimen was identified as the closely similar L. rossica, a mainly upland species; but further research established that L. picta was the correct determination. Similarly, specimens in the Natural History Museum collected in Kent during the 1950s by d’Assis Fonseca as L. rossica were also shown to be L. picta. There were no British records of the latter species between 1956 and 2009. Since its rediscovery in Kent in 2009, this tachinid has spread north rapidly and has now reached Merseyside. As the family is probably under-recorded, this insect could be more widespread than current observations suggest.
I am grateful to Phil Brighton and Chris Raper for correspondence on the identity of L. picta. Natalie Hunt kindly interrogated iRecord for the current distribution of this species.
Bentley, H. & Raper, C. (2010). Linnaemya picta (Meigen, 1824) (Diptera, Tachinidae) new to Britain. Dipterists Digest 17 (1): 77-78.