Thursday, March 4, 2010

acmon blue ~ 03/04/10 ~ Carmel Valley Road

acmon blue on rape mustard
Plebejus acmon on Brassica rapa

I'm not positive about this ID. Usually I ID based on what's common, in this case an acmon blue, or simply state I don't know. However, it could be a lupine blue (Plebejus lupinus), because from above there's an obvious black border on the inside of the hindwing's orange band and the forewing black border is fairly wide. Then again, it could be an early spring acmon blue female. Erg! Can anyone help me with this ID?

It was happenstance that I even captured this butterfly on camera, because I jumped out of the car to get a close-up shot of the yellow flowers which covered the hills where Carmel Valley Road meets G17. I'll post pictures of the hills and ID the flowers later.

ps 03/07/10 - On a whim, I queried Art Shapiro, professor at UC Davis and author of Field Guide to Butterflies of the San Francisco Bay and Sacramento Valley Regions, about this butterfly ID. He was kind enough to promptly reply, "It's a female acmon of the early-spring phenotype "cottlei," but abnormally heavily-marked on the lower surface--so much so that it superficially resembles a Euphilotes battoides! The ID is made easier by the fact that nothing else but acmon would be out this early in the year on the central coast (or almost anywhere). Even at sea level, lupini--which is always found in chaparral in the central Coast Ranges--wouldn't be out before April (or May!). The flowers appear (I can barely see any leaves) to be either Brassica campestris or Brassica napus, both naturalized weedy Old World mustards. Thanks for the kind words." Thank you, Dr. Shapiro!


Erica Lea said...

You're way ahead of me! I have some photos from last year of a butterfly that looks very similar, and wasn't sure. I actually use the same site as you, too. The other thing I do after I have some possibilities is to look on Flickr and see if I can find more photos to compare (can work for both birds and butterflies). Are they mustard flowers? Also, for wildflowers, I really like this site: Great catch whichever this little beauty is!

Nature ID said...

Hi, Erica Lea. Thanks for the link to the great wildflower ID guide. I checked out your blog and particularly love your bird pictures! And, I hope life is treating you better these days. I added a ps to this post, so check it out!