Wild Ginger and Ants

I spend a lot of time looking for the shyest wild flower of spring, wild ginger, Asarum canadense.  To find the blossom you have to get down to its level and start lifting up the heart shaped leaves.  The petioles are pubescent with soft short hairs requiring close inspection.  You can't find the buds unless you push aside the leaves and push away any leaf litter. 

The flower lays on the ground at the base of the plant, three rusty brown petals with pointed tips.  It looks depressed, too humble to bother lifting itself up to look around.  Why would a plant have its flower hidden in the ground litter?  "The better to pollinate, my dear."  Since the ginger spreads by multiple rhizomes the flower has to attract pollinators the hard way.  It emits the scent of decaying fruit, attracting beetles and flies which are fooled into picking up pollen then fall for the same trick at a neighboring ginger next door.

Ant hauling an elaiosome - Eva Colberg

That is not ginger's only insect trick.  Its seed has an elaiosome, a fatty cap which is like the finest cuisine to an ant.  After a little taste, the ant drags it back to its nest where it is consumed by the clan.  Then they drag the seed out to the trash heap which may also be their toilet.  Seed + fertilizer = growth plus it was protected from seed eating animals along the journey, a win-win for the mother ginger.  This ant-seed dispersal is called myrmecochory and is fully explained by Eva Colberg from Missouri Botanical Garden.

Taste testing a wild ginger treat

Lifting off the ground

Naturally I had to see this for myself.  I put the tiny wild ginger seeds on the deck and waited for the ants to show up.  Nothing would happen for several hours and then they would all disappear while I stepped away.  Finally I caught this one above taste testing an elaiosome.   After rolling it around it finally got a grip, lifted it slightly off the ground and then took off at a frantic pace as seen in this video.  This is the eastern black carpenter ant - Camponotus pennsylvanicus or Campy for short, which we discussed in this blog.

Campy is a very common ant.  Dr. Eleanor's Book of Common Ants calls them "one of the largest and friendliest ants, black carpenter ants that lumber through your lumber."  They are omnivores and will supp on fruit and dead insects.  The workers will groom aphids like a dairy herd, collecting honeydew from their backs to take back home in their tunnels in dead wood.  I found this one in an open hickory leaf stem gall as the aphids were leaving it.

Back to the flower of A. canadense.  It is a shame that it hides in the dirt as it is actually attractive if you look deep inside.   My favorite photograph is the one looking like a little bird with a Santa Claus beard.

More detail on Wild Ginger is at Illinois Wildflowers.

Dr. Eleanor's Book of Common Ants is an excellent introduction to the world of myrmecology and it is free here!

Thanks as always to Dr. James Trager for the ant identification and education.