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Sunday, September 16, 2012

Twelve-spotted

It's taken a while, but I've slowly learned that September is a good month to look for dragonflies on Bodega Head.  Warm days with calm winds increase your chances of encountering them.  The dragonflies that appear at this time of year are often species known for long-distance movements along the coast.  

Earlier I posted pictures of a Spot-winged Glider (Pantala hymenaea) and Variegated Meadowhawk (Sympetrum corruptum).  Recently I've also seen Black Saddlebags (Tramea lacerata) and Common Green Darners (Anax junius).  On 12 September 2012, I spotted my first Blue Dasher (Pachydiplax longipennis) on Bodega Head.  It's not necessarily a rare species, but I hadn't seen one on Bodega Head before. 

On 10 September 2012, I photographed this Twelve-spotted Skimmer (Libellula pulchella) in the dunes. 


Note that there are three black spots on each wing — at the base, in the middle, and at the tip.  The pale yellow stripes along the side of the abdomen form a continuous line.  The short appendages at the tip of the abdomen reveal that this is a female.

Here are two more shots from different angles.



Interestingly, she appeared in almost the exact same place where I photographed a male Twelve-spotted Skimmer in September 2010 (see next photo).


The males also have a total of 12 black spots on their wings, but as they get older they develop prominent pruinose white spots and a pruinose abdomen.  (Pruinosity refers to a wax-like coating; it's usually white or blue.  You can see the same sort of "bloom" on fruit such as plums or grapes.)

Look for these species in warm, sunny spots that are out of the wind.

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