Monday, November 9, 2020

Luna Moths and their interesting tails


The flawless beauty of a freshly emerged male Luna Moth, Actias luna. This one was resting and drying on a small tree seedling in Shawnee State Forest, Scioto County, Ohio, WAY back on April 29, 2011. While there is much to admire regarding the moth's elegant architecture and coloration, it is the tail streamers that often invite comment.

I think much of the long-standing conventional wisdom was that the tails mostly serve as camouflage of sorts, to help a moth perched among plant matter better blend with its surroundings. At least that's what I always thought. The tails undoubtedly do serve that role, too. I've seen Lunas hanging among green leaves on occasion, and the streamers do seem to break up its shape.

But there seems to be a more critical role for the tails...

I photographed this Luna on April 27, 2014 in Fayette County, West Virginia. While it is also a pretty fresh, recently emerged moth, this insect has apparently had a rough row to hoe. The tail streamers are nearly gone, and a big chunk is missing from the wing on the left.

Recent research has convincingly demonstrated that the tails present a false flag to hunting bats. The fluttering streamers when the moth is in flight creates an acoustic signal that dominates an approaching bat’s echolocation sonar. It fixates on the tails and, more often than not, ends up clutching a piece of tail while missing the body. The moth escapes, still with an opportunity to reproduce. Laboratory experiments featuring normally tailed moths and Lunas that had their tails removed, and a Big Brown Bat (Eptesicus fuscus) showed that the bat caught only 35% of the moths with tails, but its success rate skyrocketed to 81% with the tailless moths.

I am about sure that's what happened to the moth in the photo above - a survivor of a failed bat attack. The V-shaped bite mark on the wing, especially, is the calling card of a bat.

My whole life has been moths for a while, because of a book project, and it has me frequently dipping into the files and dredging up old photographic chestnuts such as these moths. 


Anonymous said...


What moth book are you working on, and when will it be published?

We will really miss Mothapalooza! The diversity of plants and insects in that part of Ohio is amazing.

Loren and Babs Padelford
Bellevue, NE

Jim McCormac said...

Hi Loren and Babs, it’ll be called “Gardening for Moths in Ohio and the Midwest”, or something close to that. Should be out in about a year.

Mothapalooza will take place in 2021, barring another covid type disaster. More on that will be forthcoming

Unknown said...

your website is fabulous. it should be required reading for all lovers of the natural world.

Jim McCormac said...

Well, thank you! What a nice compliment 😀

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