Sunday, August 30, 2015

A second Michigan Locality for the Giant Spreadwing

For many years, a few of us wondered if and when Archilestes grandis, the Giant Spreadwing would be found in Michigan.  This giant lestid has been spreading from the SW to the NE gradually, and I believe that it's because of anthropogenic habitat change we are seeing the species farther and farther northward and eastward.  Julie Craves and Darrin O'Brien found a small colony of A. grandis in Wayne Co. ten years ago (2005) [Craves, J. 2006. Great Lakes Entomologist 39 (1&2):88-90].  The small stream in Livonia has had a colony for at least the last decade, but no other locations had been found.  
Yesterday, I was almost apoplectic when I saw a Giant Spreadwing in my front yard.  I went off to get a net, but when I got back it was gone. Drat.  No photo, either.  This species is hard to miss, as it's at least 2x the size of any other Lestes in our area, and deserved of the "Giant" category.  I looked several times afterwards, but did not see the spreadwing again.  Until today.  This time, I walked out into the garden with the insect net -- a movement near the Hydrangea shrub -- and there it was. A female Giant Spreadwing!  I carefully moved closer and snagged the specimen with my net.  Wow! 
I was elated over being able to catch and voucher this elusive species. In my front yard, no less.  Really, that's like being an expert in meteorites and having one fall in your yard.  Twice.  

So, naturally, I had to wonder where this female came from.  It had to be relatively close by, but where?  Aha! County Farm Creek, which is a 10-minute walk from my house.  So, with my D200 and 200mm micro-Nikkor, I walked over County Farm Park (CFP).  Three years ago the county finished the constructed wetlands and the improved creek channel. I walked down to the creek where the water was pooled up, and there, under the overhanging willows, within a minute of arriving at the water, I spotted a male Archilestes grandis! I checked other spots along the creek, and had 10 sightings, 9 males, and 1 female. I watched several males, and they typically flew off to catch a gnat and then return to where they were perched to eat it. I feel as though the female in my yard was an omen. 

Looking at the site, I think the arrival of the Giant Spreadwings is fairly recent, and was possibly facilitated by the improvements in County Farm Creek and the constructed wetlands.  Willows and other small trees now grow on the edge of the banks, shading the stream, and provide ideal perch sites for the damselflies.    The image of County Farm Creek should provide a reference in looking at other small, slow streams elsewhere in lower Michigan.

So, this makes two localities in SE Michigan.  Where else will we find them?
Oh, and the voucher data is: MICHIGAN: Washtenaw Co., Ann Arbor. 2104 Needham Road. 30 August 2015. Mark F. O'Brien.


Sarah Somes said...

Hello Mark! I work in Wixom and saw a bright red dragonfly today. Can you help me find the species? Scarlet darter keeps popping up but sources (aka google and wikipedia) say they don't exist in the USA. Thank you for your blog! I'm looking to learn more about Dragonflys and appreciate your work.

Mark O'Brien said...

Sarah, it is most likely Sympetrum obtrusum, the white-faced skimmer.