Male, Aragón, July 2011
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Male, Aragón, July 2011
Male, Aragón, July 2011
Male, Aragón, July 2011
Male with Agenjoi's blue, Aragón, July 2017
Male, Aragón, July 2011
Male, Aragón, July 2017
Male with no stripe
visible, Aragón, July 2011
Male with weak stripe, Aragón, July 2011
Male with strong stripe, Aragón, July 2011
Female, Aragón, July 2011
Female, Aragón, July 2011
Female, Aragón, July 2017
Female, Aragón, July 2017
Female, Aragón, July 2011
Female, Aragón, July 2011
Female, Aragón, July 2011
Distribution
Forster's furry blue is
restricted to
northern Spain. Until relatively recently, some of its populations were
treated as a subspecies of furry blue but it has now been established
that this latter species flies only in the South of France and Italy.
All Spanish furry blues are Forster's. It is a butterfly of hot,
flowery waste places and scrub, often flying on the margins of
cultivated land and sometimes in open woodland. I found it flying in
many small but often numerous colonies spread over a wide area in
Aragón in July 2011 and 2017.
Males are easy to identify, given that there is no geographical overlap with furry blue. They are a bright, silvery blue above with a large, worn-looking, brownish area at the base of the forewings.The white stripe beneath the wings varies greatly in prominence and may be almost absent. Females are harder because of the presence in the same areas of Ripart's anomalous blue. The latter typically has a stronger white stripe beneath, though this is short and less prominent in ssp. agenjoi, which I have found flying with Forster's furry blues, and usually stronger submarginal markings. I have yet to establish any really definitive way of telling these apart, however. Fortunately, colonies tend to be relatively dense and where there are females (of either species), males are not far away.
The adults fly in a single
brood in July
and August. Eggs are laid on the foodplant, sainfoin, and the species
hibernates as a small caterpillar.