allison_reid99's picture

Something blue?

Observed: 28th May 2010 By: allison_reid99allison_reid99’s reputation in Invertebratesallison_reid99’s reputation in Invertebratesallison_reid99’s reputation in Invertebratesallison_reid99’s reputation in Invertebrates
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Description:

Seen on arable land. Suspect this is the common blue ..... but finding it difficult to tell from pictures of Adonis blue....what is distinguishing feature. Unfortunately, didn't get shot with wings open.

Identifications
Species interactions

No interactions present.

Species with which Common Blue (Polyommatus icarus) interacts

Comments

JaseJ's picture

Common blue

Pattern on the underside of the wings isn't right for the Chalkhill Blue and there's a bit too much orange in the spots at the edge of the forewing for the Adonis, in my opinion. Add in the location and that the photo seems to suggest it is on the small side and I'd go for Common Blue. You'd probably need to see the upper surface of the wings to be sure though.

Have a look at the images on www.ukbutterflies.co.uk for some examples.

The Brown Argus has very similar patterns on the underside of the wings too and you can't actually see the area where the diagnostic spot is.

rimo's picture

Additionally, you can just

Additionally, you can just about see the white border of the far forewing, and it's clearly the unbroken white border of Common Blue, rather than the chequered black and white of Adonis, which also doesn't occur round Cambridge. Chalkhill won't be flying for another 6 weeks

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Kluut's picture

Website and books here

I used both the ukbutterflies website and books here and came to the conclusion that it was not a common blue because of the more or less central pale spot on the hind-wing that all show on chalkhill and adonis blues, but not on common

rimo's picture

Commons are massively

Commons are massively variable, and often do have the central white spot - it can be seen in some of the 'other observations' section. This also has more orange in the lunules on the forewing underside than Adonis males (this is a male as it's grey rather than brown, and has the blue flashing near the body)

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