Why was the Scotch Argus thought to be absent from Southern England?

[PhilBJohnson]

Apart from it's name suggested to someone it might stay in Scotland, what was it about the Scotch Argus' life cycle and habitat requirements, that left it absent in Southern England?

[CallumMac]

Some like it hot, and this ain't one of them. Aldina Franco's work in the early 00's (https://onlinelibrary.wiley.com/doi/ful ... 06.01180.x) shows quite clearly that recent distribution changes in this species are strongly linked to warming climate - populations go extinct at the hottest (most southerly, lowest elevation) sites first.

I'm not sure why heat causes them such a problem, but for many grass-feeding species, host-plant desiccation is a real problem - so perhaps their host-plants are not very drought-resistant.

[PhilBJohnson]

"one person might have said that they were going to introduce SA in Wales, keep an isolated population long enough, for their wings to change colour, then call them a Welsh Argus.
Another person, then might have accused the first person of wanting to introduce an invasive species to Wales!
Those were the kind of arguments that national habitat managers were faced with.

Kind regards (take care Callum).