Primitive Dragonfly Awes Group!

 

Written by Curator Emeritus Bob Glotzhober

On May 31st, I had the privilege of leading a tour at Cedar Bog Nature Preserve near Urbana for a group from the Cincinnati Wildflower Preservation Society. As we were walking through a section of the swamp woods, I was discussing the impact of the exotic invader, the Emerald Ash Borer. Right on the edge of the boardwalk was an 8-inch-diameter Black Ash, with abundant signs of the Emerald Ash Borer (EAB for short). One of the signs of infestation is what is known as epicormic branching. As the EAB larvae cut off the flow of water and nutrients, the top of the tree begins to die. Lower down, often at eye level, the trees natural defenses cause it to send out new small branches directly from the trunk. By the time these epicormic branches appear, the tree is well on its way toward total death.

Gray Petaltail male eating another.

As I reached out to place my hand on the trunk and explain the fresh new branches, one of the Cincinnati members stopped me, noticing that my hand was only a foot away from a pair of large dragonflies. What everyone in the group then saw (and anyone with a camera was able to photograph) were two large, three-inch-long brown and black dragonflies. They were both male Gray Petaltails, and the top one was eating the bottom one! Gray Petaltails are from one of the most ancient surviving families of dragonflies, and are often very tame. I have actually grabbed them off of tree trunks using my fingers, and I know at least half a dozen others that have done the same! But the live, successful predator in this case was even more tame than normal, and continued to eat his equally large prey as we watch and photographed him. While we watched, he was eating the head. Presumably, if we had spent the next half hour, we would have seen him move down and consume the thorax as well. As I was leading the tour, I had not brought my camera but participant Joe Bens was able to send me the photo shown here.

Eastern Petaltail.

Gray Petaltails have a very sporadic distribution across Ohio. Their typical habitat is either open, sunny fens like we have at Cedar Bog or semi-sunny, wet seeps in forested habitat. I believe that prior to deforestation, both these sunny seeps and the Gray Petaltail were much more widespread. Deforestation, however, resulted in a lot of the wet seeps and springs drying up, greatly reducing habitat for the Gray Petaltail. By 1940, Ohios forests had been reduced from 95% of the state to only 12 to 15% of the state. In recent years forests in Ohio have recovered to now covering about 30% of the state, but these large dragonflies have not re-inhabited many areas that might now be suitable. Gray Petaltails seem to be much slower to recover than the forest seeps they call home. Cedar Bog is one of several good places to see this species, and sometimes they even land on visitors!

If you want to learn more about dragonflies and their close relatives the damselflies, then you might want to join a group of us at the West Woods Nature Center in Geauga County on Saturday, June 21st. The annual meeting of the Ohio Odonata Society (OOS) will start at 9 a.m. in the nature center building with several short talks and a brief business meeting. After a break for lunch (bring your own no nearby facilities), well head afield to see and photograph whatever Odonata (the order of dragonflies and damselflies) we can find. Long-time members of OOS are all friendly and eager to share information with novices. Several members are authors of dragonfly books and booklets and several are excellent photographers. Famed NE Ohio nature photographer, Ian Adams, will be leading one of the morning talks on how to photograph Odes and help will be available in the field as well. Species that might be seen (never any guarantees) include Swamp Darners, Cyrano Darners, Amberwing Spreadwings and with a lot of luck Southern Pygmy Clubtails!

Why not join us for the day? The meeting is open to anyone and everyone you don’t have to be a member of the Ohio Odonata Society to attend. Furthermore, as they say on the radio ads, It’s Free! Visit the website for the West Woods Metro Parks here and for more information on the meeting agenda visit Ian Adams website here.

Bob Glotzhober
Curator Emeritus of Natural History

Posted June 16, 2014

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