If you spotted this dragonfly out in the wild would you guess that it was called a blue dasher? Probably not but it is indeed a blue dasher. Like birds, many dragonfly females look different then the mature males.
When a male emerges from its nymph form it will look like the females. After a short time it produces a powdery substance which covers most of the thorax and abdomen leaving it a powdery blue color. This is where the blue dasher gets its name.
Identifying dragonflies from pictures can be a tricky task. Organizations like Odonata Central will not even consider photographs as a record of a sighting for many different species because they look so similar to a different species.
So if you want to take pictures of dragonflies the best tip that I can give you is to try and photograph them from as many different angles as possible. If you are photographing them to turn into a survey as a record the best thing to do is to net them and then photograph them in hand making sure to photograph distinguishing features.
Or if you happen to find a cooperative dragon, like this immature blue dasher, you can move around the subject taking pictures from different angles, in this case front view, abdomen view and profile.
The blue dasher is one of our fairly common skimmers. They are usually found around lakes, ponds or slow moving rivers and streams. These blue dashers were photographed at the William O'brien State Park where the St Croix Rivers overflows into Lake Alice.
These are photos of mature blue dashers. Immature blue dashers are yellowish in color with brown stripes on the thorax. As they age they produce pruinose, a powdery substance, which covers the abdomen and give them their blue color.
All of these pics where taken at Purgatory Creek Back on July 23rd. It is kind of fun to look at these pics and remember sweating out in the wetlands, back in July, when the high temps this week are in the 30s if we are lucky.
The first three pics are of eastern pondhawks. Eastern pondhawks begin life bright green in color. Females stay this green color but as the males mature pruinosity covers the abdomen and and thorax and gives it the powdery blue color.
Another dragon that is very similar looking to the eastern pondhawk is the blue dasher. They also get a powdering blue color as they mature due to pruinosity but the pruinose on the blue dasher does not cover the thorax like it does on the eastern pondhawk. 
Blue dashers typically hunt from a favorite perch. Both males and females will defend their preferred feeding perches leaving the perch only to catch prey or fend of a rival.
The eastern amberwing is one of the smallest dragonfly in our area. Since they are usually less then an inch long, the elfin skimmer is the smallest dragon in North America at .8 inches, they are often easier prey then other dragons. To help keep themselves from becoming prey they will often mimic wasps, which they resemble in size and color.
I still also have quite a back log of posts that will probably last me through most of the rest of 2008. Like these dragonfly pics that I took back in July at Fort Snelling State Park.
The blue dasher hunts by making short flights, from a favorite perch, in serch of prey. Both the male, pictured above and the female, which is black and yellow striped, will defend a favorite perch from invading dragons.
I was pretty excited to get a photo of the photo of the dragon above. I have photographed several male eastern pondhawks before but this was the first female that I ever captured. The males are primarily green also but most of their thorax and abdomen is covered in in a slate blue pruinose.
There were also some more Halloween pennants around. Unlike the ones that I found at Purgatory Creek these where the orange color which most likely mean males.
When I saw this pennant through my lens finder the first thought that came to my mind was that it was laying eggs. That idea quickly dissappeared though because it was up in the air, it is probably a male, and eggs are laid from the end of the abdomen. The tiny dots that you can see in the photo are actually water mites. Water mite larva often attach to dragon fly larva and feed on its bodily fluid. The Mites, realatives of the wood tick, continue feeding on the dragonfly as it transforms into an adult. Eventually the water mite larva will drop off of the dragonfly and molt into its nymph form. As long as there are not too many mites the dragonfly can live as a host to these tiny parasites.
Back in the middle of July I found a few dragons. The first one, pictured above, is a great face shot but the angle makes it difficult for me to ID it. Maybe if I had some more experience I would not have problems but this is only my second summer photographing dragons. I believe that it may be a juvenile female blue dasher but I am not 100% sure. The juvenile females are brown with yellow markings on the thorax and abdomen. As the male and female age their abdomen turns blue with pruinose.
This dragon is definitely a male twelve-spotted skimmer. We know that he is male because the pattern of the spots on the wings as well as the white spots, which the females do not have. He has probably been around for a while because his abdomen has turned blue with pruinosity.
This female widow skimmer also looks like she has been around a while, at least in dragonfly terms which is measured in days or possibly weeks. You can see the age in her wings. The male widow skimmer has white bands on the wings located just outside the black patches at the base.
A member of the Libellulidae family the blue dasher is a common dragonfly seen at lakes ponds and slow moving streams through out the US and into Mexico and southern Canada. They prefer lower elevations and as such are not found in the Rocky Mountain Region. 
Blue dasher hunt from a favorite perch, making short flights to catch small flying insects and then return to their perch.
Both Male and female of the species will defend good feeding perches.
Immature blue dashers and females have a green face and thorax. Their abdomen is brown with with a pair of yellow dashed lines running across the top which end before segment 10. As the dashers age the abdomen changes powdery blue with pruinose. Although the females do turn blue also they do not get as blue as the males do.
