K W Rowley – kevrowley@live.co.uk 

I can confidently report that Ranatra linearis – water stick insect, is now in Scotland and was found by myself in Lagoon 1 (NX44485316), VC74, RSPB Crook of Baldoon, Wigtownshire, Scotland on 21/6/2023. Like many species in the UK Ranatra linearis has been moving northwards. It has taken it a while, but for those that have seen it make a strange laboured effort at flying, they are not surprised.   

This specimen was found at RSPB Crook of Baldoon which is a mudflat and salt-marsh area part of the much larger Solway Firth SPA. Behind a bund, marking the high tide line, the RSPB have been improving and diversifying the grassland to create safe areas to encourage breeding waders. They have created a number of ditches and also 2 lagoons, surrounded by electric fences, to keep natural predators out. The first aquatic records from the site were taken in 2018 (Foster and Merritt 2021) and highlighted it as a fantastic area for invertebrates, with new county water beetle records.     

I was taking part in a Colsoc meeting and sampled both lagoons and the ditches with the help and support if Ivan Land who is the RSPB warden. I only found one sample of Ranatra linearis in lagoon 1 near the car park. It was a juvenile and was amongst many other aquatic juveniles. The water levels had been kept fairly high and Glyceria sp, Carex sp and Potamogetan sp. were present along with with flooded grasses and some bare earth. 

Also present in the lagoons were other water bugs some very under recorded including Callicorixa praeusta, Corixa punctata, Gerris odontogaster, Gerris thoracicus, Notonecta glauca, Notonecta viridis, Plea minutissima, Sigara dorsalis, Sigara distincta, Hesperocorixa castennea, Hesperocorixa sahlbergi, Hesperocorixa linnei, Saldula pallipes, Saldula opacula and Microvelia reticulata.  

In 1985 Thomas Huxley (Huxley, T. 2003) drew its Northern boundary as Nottinghamshire with 2 records one near Ranskill and the other from Gateford Common, Worksop in 2001.  

Huxley 2003 Tony Cook 2016 

Current records iRecord as at 12th July 2023 Ranatra linearis from RSPB Baldoon 

In 2016 Tony Cook created a new online Atlas  (Aquaticbugs.com ) and the range had extended into Cumbria and Newcastle area. The current most northerly record was found last year near Carlisle by Steven Routledge (Bilton & Routledge 2022). Other northerly records were at Carleton Hill Fishery NY45355069 just south of Carlisle, 27//3/2022 by Samantha Jones and at Gosforth Nature reserve NZ251703, 21/10/2021 by Charlotte Rankin. 

It has likely been in Scotland for a while as recent correspondence with Bob Merritt has identified that he has a record from Loch Mackie, NX808489 (VC73) 24/4/2022 which is likely the first record for Scotland, and two other locations near Colvend, NX85 in June 2022 and near Sandgreen, NX55 in Oct 2022. These records have yet to be submitted to NBN Atlas.  

There are many more deep pond and pools with vegetation in Scotland that would be suitable habitat for Ranatra linearis. I am sure this will increase it’s spread much further into Scotland in the coming years. 

Acknowledgements 

Thanks to Bruce Philp and Colsoc for arranging the field trip. Ivan Land for escorting me around the reserve and Garth Foster for helping get to the bottom of the more recent records.  

References 

Huxley, T. 2003. Provisional atlas of the British aquatic bugs (Hernimera, Heteroptera). Huntingdon: Biological Records Centre.  

Cooke, Tony. 2016. Aquatic Bugs.com  

Foster G.N & Merritt. R. 2021. Water Beetles of Wigtownshire, VC74 – new records and a critical review of earlier ones. The Coleopterist 30(1), April 2021 

David T Bilton and Steve Routledge. 2022. Global change reflected in the water beetles (and bugs) of a Cumbrian Tarn. Lakeland naturalist 10/2 October 2022