Tuesday, August 24, 2010

Spreadwing Species

I have just begun chasing dragonflies around the backyard and am finding them exceedingly difficult to identify.  I am somewhat confident that the damselfly in this post is a species of spreadwing.  According to the Mississippi National River and Recreation Area website, the distributions of the Minnesota spreadwings and damselflies are not well known.  At least six species might be found in this region of the state, but identification requires closely examining a captive.  Whatever species this may be, I was amazed by the intensity of its azure eyes and by the yellowish racing stripe along its sides.
Resting spreadwings hold their wings back in a V-shape, unlike dragonflies that hold their wings straight out and damselflies that keep their wings against each other. Unlike most dragonflies that survive as larva under water during the winter, some spreadwings inject their eggs into vegetation just above the waterline.  In winter, the eggs go into a suspended state. After winter, as water levels rise, the eggs begin growing again.  Thus spreadwings are among the first dragonflies to appear in the spring.

Since posting this blog, I received a note from Scott King.  He writes "The spreadwing is even more exciting. I'm fairly certain it's a Great Spreadwing (Archilestes grandis) and a new state record...The closest records for this species are for Iowa and are from August and September. Take a look at the dot map for the species at Odonata Central (http://www.odonatacentral.org/): type in Archilestes grandis for the taxa. It's a significant find. One reason for recent survey work is to document range expansions to the north due to climate change; this would certainly suggest such an expansion.

1 comment:

  1. This picture ought to be next to the word "blue" in Websters. Now that is true blue if I ever saw it.