Article on mobility of SSB by Harry E. Clarke

[PhilBJohnson]

"The Silver-studded Blue is a butterfly of early successional habitat [1]. Unless something is keeping the habitat in check, early successional habitat develops into late successional habitat with heathland (one of the habitats occupied by the butterfly) degenerating into woodland. For an early successional butterfly to survive, it must be able to find new habitats. If it is very sedentary then it will soon die out, as the habitat becomes unsuitable."
Ref: A New Article on the Mobility of the Silver-studded Blue
Posted on October 30, 2019 by Harry E. Clarke

There might have been a small isolated site that was managed specifically for the Silver-studded Blue (SSB) so that a habitat was kept and managed as "early successional". For the SSB species to survive in that habitat, it needed not to, fly out of it's small habitat range, never to return. Over many generations, such butterflies would evolve to be less flighty as evolution would not reward those butterflies leaving their specific habitat needs.
Butterflies (in the United Kingdom) usually complete their life cycles in one year or less, so evolutionary changes within a butterfly species in isolated habitats, might be seen in fewer years, than with individuals within an animal species that lived to be much older.
I thought that it was only really fair to compare such SSB butterflies of isolated habitat, with those found in Europe which had much larger or networked habitat areas, that had remained over many years. Those butterflies of not so isolated habitat, might be found to be more flighty (less sedentary), unless the isolated managed site, included imported stock from the larger habitat area.

In Surrey, I was specifically interested in the population of SSB on Fairmile Common. This was thought to be a re-introduction of the species and from my understanding, the habitat for this butterfly was only suitable on a relatively small part of the Common, the population being somewhat isolated (by "isolated", I meant another suitable habitat was not within the flight range of an egg laying female). How that population was established and maintained with genetic diversity was also of interest to me (the population obviously was not established and maintained from the brood of just one single female).

Kind Regards