Thursday, May 28, 2009

vivid dancer
Argia vivida

I don't have a good ID book for odonates.

We also saw several large, very fast, red dragonflies. I would initially guess that they were big red skimmers (Libellula saturata), but the wings seemed to be entirely red. It's possible they could have been dusty skimmers (Sympetrum illotum), but they seemed bigger than 40 mm. I may never know since I wasn't able to capture a picture of them.

ps 02/06/11 - Well, I finally looked into this damselfly, which was originally posted as an unknown. First, it's a bluet (Enallagma spp.) for sure, because it's wings are held close to the body, whereas dancers (Argia spp.) hold their wings up and away from the body. Since the abdomen appears mostly black from the top view, I've narrowed it down to 2 species: E. praevarum (arroyo bluet) or E. carunculatum (tule bluet). My picture does not clearly show the male appendages, so the next best thing is to consider the habitat. According to Don Roberson (his site is linked in the species names above), arroyos prefer rivers and small streams, while tules prefer marshes and ponds (both appropriately named). Unfortunately, this was taken near where Los Padres Dam spills into the Carmel River. Simply based on photos and previous records from Carmel River, I'm leaning towards E. praevarum. Thanks everyone for your comments!

pss 02/10/11 - Sigh, I've made another correction to the ID above, but I'm keeping my previous postscript to show how I reasoned my incorrect ID of a bluet. Kind thanks to Jim Johnson at Northwest Dragonflier and Odonata.Bogfoot.net for helping me learn what to look for when identifying damselflies. With his permission, here's a snippet from his e-mails, "...because of the angle the wings are obscuring the abdomen and that's why there is so little pattern visible there. One thing that indicates that it's a dancer and not a bluet is the extent of blue at the end of the abdomen. On all the western bluets, the blue is limited to segments 8 and 9, and 10 (the last smallest one) is largely black, especially on the top portions. The western dancers (the blue ones, anyway) are blue across all three segments which is what this ones shows." Jim goes on to say, "The wing position is helpful, but you can't rely on it for distinguishing dancers and bluets." I wish Kathy Biggs, author of Common Dragonflies of California, had stated this versus making a point of dancers (with "wings held above abdomen") and bluets (with "wings at rest held alongside abdomen"). Don't get me wrong, her book is great for novice odonate fans like me and I still recommend it.

11 comments:

spookydragonfly said...

Great capture of your Bluet damsel...question is...which Bluet is it?! Damsel I.D. is so very tricky!

Nature ID said...

Hi, Spooky,

Is there a quick way to distinguish, while in the field, between Enallagma sp. and other blue-tipped damselflies (e.g., Argia sp.)?

I have more odonate pics from past hiking dates, but haven't gotten around to posting them, yet.

Thanks!

Nature ID said...

Btw, do you have Legler and Westover's "Common Dragonflies of Wisconsin"? I just picked up a copy of Bigg's "Common Dragonflies of California." What's up with this "common" moniker in relation to odonates???

Nature ID said...

Hi, again, Spooky. I had a few questions about dragonflies and thought of you, but you don't seem to be blogging anymore. I hope all is well for you.

Imperfect and tense said...

Hi Katie, very intrigued by your mystery damselfly. Unfortunately, we haven't got one like this in the UK. It's mostly like our Blue-tailed Damselfly, but the broad antehumeral stripes are more like a Common Blue. The purple colour is just gorgeous. The Admiral reckons he's got a book of American odos, so perhaps we can help after all. More soon... !

Nature ID said...

Thanks, Graeme. I have some better resources since I originally posted this, so maybe I'll take a second look into the ID.

Imperfect and tense said...

Hey, you can't have enough odo resources! The Admiral has way too much time on his hands at the moment (off work with a bad back) and reckons it might be a Pacific Forktail. Were you able to take other photos from a different angle? Our season is coming to an end over here, Spring seems a long way off :o(

Jim Johnson said...

Hi Katie, that looks like a male Vivid Dancer (Argia vivida) to me. I'm enjoying your blog! Jim

Nature ID (Katie) said...

Hey, Graeme, I finally got around to ID'ing this sucker. This one was too big and the thoracic markings don't match the Pacific Forktail: http://creagrus.home.montereybay.com/PacificForktail.html

Jim, thanks for visiting my blog and giving me a nudge to look into this particular ID from 2009. I have more odonate pics and hesitate to post them until I can get a better handle on the IDs. I know my photos aren't the best quality.

As is typical, I've corrected the ID above and added a postscript.

Jim Johnson said...

I'm always happy to help ID odonates, so I'll be watching for them on your blog. Feel free to e-mail them too, if you'd like.

Nature ID (Katie) said...

For those who may be following this post, I've added yet another postscript (pss is intentional, even though I know it should be P.P.S.)