Gossamer Tapestry

Reflections on conservation, butterflies, and ecology in the nation's heartland

Saturday, July 18, 2009

Michigan Myrmecophily

This post is for Mark, who has been asking me to write something on this topic for over a year now.

Allegan State Game Area, Allegan County, Michigan

On Wednesday the Imperiled Butterfly Conservation and Management Workshop traveled from Toledo to the Allegan State Game Area in Western Michigan. Our goal was to see the population of Karner Blue butterflies that was used as the source of material bred for release in Ohio. In addition to a huge population of federally endangered Karner Blues, Allegan is home to a sizeable population of Edwards Hairstreaks, an uncommon butterfly of oak barrens.

Edwards Hairstreak (l) and Karner Blue (r) slurp some milkweed nectar

Karner Blues and Edwards Hairstreaks are both members of the gossamer winged butterflies, or Lycaenidae. Along with many other lycaenid butterflies, they have a close relationship with ants, called myrmecophily. The relationship involves the caterpillars.

Female Karner Blue (Plebejus melissa samuelis)

A Karner Blue caterpillar emits scents and ecven sounds that attract certain species of ants. When they detect the caterpillar, they approach it and begin stroking it with their legs and antennae. The caterpillars have special organs on their skin that emit droplets of a nutritious liquid called honeydew. The ants consume the honeydew, and drive off parasitic flies and wasps that may try to attack the caterpillar.

Edwards Hairstreak (Satyrium edwardsii)

This mutualistic relationship is carried even further when the Edwards Hairstreak is involved. The ants will actually carry the caterpillars back to their nests. What starts out as a mutualistic relationship turns partly parasitic, as the caterpillars may include ant larvae in their diets. The caterpillars pupate underground. When the adults emerge from the pupae, they must quickly leave the ant mound, as they no longer produce the pheromone that calms the ants. Many species have deciduous scales. These scales quickly drop off when ants attacking the fleeing adult butterfly grab onto them.

Allegheny Mound Ant (Formica exsectoides)

At the Allegan Game Area, one of the ant species that interacts with the Edwards Hairstreak is the Allegheny Mound Ant. These were common in the area where we found the Edwards Haristreaks. Dozens of ant monds were found in the oak scrub, and getting nipped was a hazard of trying to photograph the butterflies. The mounds that they build are impressive- the largest was nearly 3 feet tall.

Huge ant mound. This one is nearly 3 feet high.

The complex relationship between Edwards Hairstreak and various ant species may in part explain why it is so much less common than the very similar Banded Hairstreak (Satyrium calanus) in my part of the country. The latter species does not share this complex relationship, and can perhaps better survive in oak woodlands that lack appropriate ant species.

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At 00:19, Blogger Gallicissa said...

Myrmecophily fascinating.
'gossamer winged butterflies' for Lycaenids is new to me, thanks.

At 11:57, Blogger Steve B said...

I'm so happy to hear that there is such a place. I'm not seeing as many butterflies as I would like to. This post is very interesting. Thanks for the cool data.

At 13:49, Anonymous Mark H said...

Unbelievable story! I' only heard the slightest one-liner about this relationship of ants and butterfly. YOUR post is FABULOUS, spectacular, and hypnotizing! THANKS, DOUG..... I LOVED this story, and MUST share it!

At 14:56, Blogger Kathiesbirds said...

Reading this makes me think that people who write horror movies must get some of their ideas from the insect world! This is truly amazing to me!

BTW, I was in Rio Rico on Friday and photographed a butterfly. I will try to post it on my blog this week. We are running hot today with temps already reaching 103 degrees!

At 15:32, Anonymous Anonymous said...

Fascinating--and beautiful photos. Thank you.

At 20:46, Blogger Randy Emmitt said...


Good read about the ants and Edward's Hairstreaks. We have them in the Sandhills of North Carolina but very localized. I did not know about the ant relationship with them.

At 22:16, Blogger Will said...

Whenever someone with your knowledge begins to talk about the insect world, I am always amazed at the complexity and wonder of it all. Thanks, Doug--and our stories have all the more impact for my having been lucky enough to see you in action on one of your specimen collecting trips.

At 08:31, Anonymous Anonymous said...

Very cool! Thank you!

At 02:39, Blogger SAPhotographs (Joan) said...

Love them all especially the Karner Blue. Ar they medium size Doug or small? Most od our blue ones like this are small like the hairstreaks.

At 05:37, Anonymous bev said...

Mark has expressed my thoughts about this piece. Terrific. I'm always amazed when I read about one of these complex relationships. That, in turn, sets me thinking of the person(s) who uncovered the knowledge. It must be quite a feeling to discover one of these mysteries of the insect world.

At 08:04, Blogger Doug Taron said...

Amila- That mane was the inspiration for part of my blog name.

Steve- I'm not surprised. The weather in your part of the world has been so bad this year that I would expect the butterflies to be adversely impacted.

Mark- I'm glad you enjoyed it.

Kathie- The movie Alien was partly inspired by the parasites that attack caterpillars. Looking forward to seeing you soon.

liliannattel- Thanks.

Randy- The more I think about it, the more I suspect that the ant relationship contributes to the local nature of the hairstreaks.

Will- Thanks so much. Can you believe that it's already three months since that field trip?

membracid- Thanks, I'm glad you enjoyed.

Jaon- Yes, our blues are also small. The Karner is smaller than Edwards Hairstreak.

Bev- I'm astonished at the amount of work it must take to figure this stuff out. The complexity of it all is one of the things that keeps me fascinated with biology.

At 11:30, Blogger Alan said...

We have a species with the same lifecycle here in Britain - the Large Blue Maculinea arion. Despite efforts at conservation it died out in 1979, but was re-introduced in 1984. I am glad to say the attempt was succesful, and it can now be found at 33 sites in south west England. You can find the article here at www.butterfly-conservation.org/article/9/103/large_blue_butterflies_back_in_britain.html

At 18:22, Blogger Texas Travelers said...

Nice post and great photos as usual.
I'll try to catch up on all of the interesting stuff that you have been doing.

I've got an ant post lined up for the near future. Rare (for this area)Pogonomymex in a secluded area on the 3500 acre Nature Reserve..

In the meantime......
A Three-Banded Grasshopper is posted.
To see the post, Click here.
Troy and Martha


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