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Y Glesyn Cyffredin - Common blue
(Polyommatus icarus)


The Common Blue still lives up to its name in many coastal districts but overall the species has suffered a drastic decline in numbers due to the relentless increase in farming efficiency. It is now almost unknown inland in the greater part of North Wales though numbers do pick up again in low-lying eastern districts. Where conditions are favourable, such as on ungrazed or lightly grazed coastal dunes, the population density can be high.


In the north of Britain the species is univoltine. In North Wales, however, there are two generations each year and second brood individuals can still be seen as late as the first week of October. In fact, the true situation may be more complicated with some first brood larvae not emerging until the following year.

The larvae feed on - Common Bird’s-foot Trefoil (Lotus corniculatus) and related plants.
The first 4 & 8th photographs show males, which are more spectacular than the female that can be mistaken for a Brown Argus.