Sunday, September 11, 2016

Watching Ants and Squashing Mosquitoes

A sketch from the little pond where this blog takes place. .... a bufflehead duckling.
Note:  I only squash three mosquitoes plus one ant, so this isn’t a tale of dread and terror; it is not a tale of carnage.  In all honesty I did squash a few more mosquitoes than just three today, but only three in the name of science.  It is a little hard to just watch when five mosquitoes are drawing blood on my arm at one time. 

Have you heard of E.O. Wilson (Edward Osborne Wilson)? … the delightful Harvard scientist known to many as the world’s expert on ants and holder of two Pulitzer Prizes, a Carl Sagan award, and many other awards.  When E. O. Wilson was a young boy, a fish spine blinded one of his eyes.  This momentary act was highly influential in Edward turning to the study of ants rather than some other kind of wildlife.  The world has been far richer for it. 

Just recently I’ve been reading E. O. Wilson’s only novel, “Anthill.”  I haven’t finished it yet, but so far it is the delightful story of a boy’s fascination with ants, how it affects his own life, and enough information to see some similarities between ants and humans.  Sounds heavily influenced by E. O. Wilson’s own life, doesn’t it?

The middle of the book describes one type of ant in great detail.  How ants in a colony have different jobs and even look different, how they communicate by means of pheromones,   …. And how fascinating it is to watch them!  The stage was set for my next dose of ‘bug watching.’  …. I know, I know.  Ants aren’t bugs.  They are insects and are classified along with wasps and bees in the hymenoptera order. 

July 22, 2016  Umpqua National Forest, Oregon, U.S.A.

When we headed upriver, into the Cascade Mountain, this morning our goal was a little pond in the high country of the Umpqua National Forest.  On the way we found a fascinating variety of insects and just now, at 5 PM, have finally reached our goal.  Shadows are stretching long, the hot of the day is easing.  The pond is lush with water lilies and a green grassy edge.  The mosquitoes are awful!
We start out walking the shady shoreline.  Oops!  Lots and lots of little toads.  Hundreds hop about within 15 feet of shoreline.  I step very carefully and hope one doesn’t zig just when I’m zagging.  Don’t want to squash those little creatures!  Just a few little frogs are there too, but mostly toads.  The toadlets have lumpy backs.  Some are basically dark, but others have dull, red spots.    

We look out carefully over the pond, hoping to spot a bufflehead family, or maybe a Barrow’s goldeneye family.  Most of the pond is still sunny.  Quiet out on the water.  When we reach sunny shoreline the toad numbers and the mosquito numbers drop.  They apparently prefer the shade. 
Nearby a junco comes down to the water edge.  He slips out of sight in the shoreline grass, but I hear the whir of water.  I’ve watched birds in my birdbath often enough to know he is having a good bath. Soon the junco hops up on a downed log to fluff and buff. 

This pond is our favorite spot to find sedge sprits, Oregon’s tiniest damselfly.  I have to look carefully to find them.  It must be too early in the season.  Lots of other damselflies and dragonflies are enjoying the sunny edge.

I’m a quarter the way around the pond, in full sun, when I pause to examine yet another log.  It’s a old, old silvery log stretched out above the high water line.  An ant is hauling a dead damsel fly down the log.  Dinner for dozens of ants!  I snap my camera up, but I’m not quick enough.  The ant and the damselfly disappear into a big crack.  How does that little ant carry something that must weigh three or four times more than he does?

 The log has been there a long time .. 20 years?  30 years?  The exterior is still firm, but two fresh piles of sawdust spilling out tell me the interior is safe haven for a colony of ants – easy digging. 

I watch a small sawdust pile first.  Several times a minute an ant head appears at one of those holes left long ago by an emerging wood boring beetle.  Little bits of sawdust sprinkle down on the pile of fresh chewings.  It is obvious several ants are doing the excavating.  Then I watch a larger sawdust pile for a little while.   The ants come to the edge of a crack to dump their load.  Two or three ants can be dumping at once.  

Suddenly I realize the second pile of debris isn’t a nice, neat pile of sawdust reaching higher and higher towards their crack, i.e. towards easy access to the colony.  Down below two ants go back and forth, back and forth, moving bits of sawdust a few inches farther away so the pile can’t grow in height.  The sawdust looks like a good sized pancake, not a hill.  The other sawdust pile I watched came out of a hole higher off the ground and in no danger of providing a path into the log.  That pile is growing taller and taller.  

Just like E. O Wilson described, I’m watching the division of labor in an ant colony.  One individual can change jobs as it grows older.  The older ants, those near the end of their life expectancy, take the most hazardous jobs such as foraging away from the protection of the nest.  Soldier ants are specialized.  They are larger, especially their heads.  Each colony has only one queen, and in some species she can live for 20 years!  Her workers and soldiers have a much shorter life expectancy, but a healthy colony is constantly producing more to replace those that die. 

I’ve been standing in one spot so long, one of the ants crawls up me.  Normally I’d just brush him off but suddenly I have a brainstorm.  I killed it.  I carefully place the still twitching ant near the entrance where the ant hauled the dead damselfly.  Healthy ants come quickly to inspect …. But they walk off.  Others come and also leave it alone.  Hummmm.   I thought they’d see it as prey, but then I remember E. O. Wilson says all ants in a colony have a distinctive odor so they know whose a fellow nest mate and who is an invader.  It takes a while for an ant to realize a fellow ant is dead. 

Well, lets try a mosquito.  I’ve got plenty bothering me, so I carefully kill one, rather than just swatting it.  I carefully place the dead mosquito about 4 inches from the entrance ( a crack on the surface of the log). Interesting that prey goes in one crack, but sawdust comes out a different spot.  Ants go near, but we wait and wait.  Just when my mind wanders back to sawdust watching, I realize the mosquito has been grabbed and is gone.  No photo. 

I’ll try another – plenty of mosquitoes to add to their collection.  I place the second mosquito nearer to the entrance.  Gone!  That was quick.  I’ll try another.
The placement of the third mosquito reminds me of Goldilocks and the three bears:  one bed was too big, one was too hard, and one was just right.  I succeed in placing the third mosquito in the right place.  Dale and I have just enough time to get our cameras on the subject when an ant grabs the mosquito.  But wait!  This ant looks a little small.  More important, this ant doesn’t go into the crack with the mosquito.  It runs like the devil ….. down the length of the log with a couple of bigger ants in fast pursuit.  I have a feeling this ant doesn’t belong with this colony.  Off they go, running down the log to the upended roots.  And suddenly seven ants pour out of another hole in the logs and race down the log too.  Fortunately for the little ant, they don’t know just where the little ant went.  By now neither do I.  I watch the chasers mill about and finally loose interest . 

After reading E. O. Wilson I think I know what I just observed.  When the little ant stole the mosquito, the ants in the area sent out an alarm pheromone.  Ants in the colony came racing out to help control the situation … but they couldn’t find the problem. 

And one last tidbit of watching.  By now about twenty minutes have passed since I placed the dead ant on the log.  Its been inspected several times, but left alone.  Now, perhaps it’s smell has changed just enough.  In any case, an ant walks over, picks it up, and drops it off the side of the log. 

It’ll be 9 PM before we get home …. But what a fascinating day.


12 comments:

  1. Wow, Elva, thank you for sharing a wonderful post with beautiful images! Your humour, deep knowledge, love for creatures touch readers. Cheers, Sadami

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  2. Yes, I am familiar with EO Wilson. Your post took me back to my childhood when I would lay on the ground and watch ants coming and going from their ant hills. Watching them bring neat bits of soil up to pile around their hills and taking food bits into the hill. I can almost feel the warmth of the soil. Fun...

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    1. Lets us hope we never loose that charm of childhood.

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  3. In case you're curious, your pictured ant is a Camponotus sp. ant (carpenter ant); I'd guess that the larger ones that chased it were also Camponotus just based on the excavation behavior and size (the nice smooth back is a good indicator of the genus for most Camponotus, particularly in N. America - I expect its not accurately portrayed in your sketch which is why I'm pointing it out). I expect you're pretty much spot-on in your observations/interpretations of the scene!

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  4. Great stuff, Elva! EO Wilson books are on our shelves, too.
    One time while riding horses around a lake, we encountered a toad migration in great numbers all along one shore. Hard to expect horses hooves missed them all. Do you think it was a migration to waters edge to mate and spawn?

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    1. I don't think it is a mating migration, but rather the little toadlets are ready to spend a portion of their life on land. They'll do their mating in the spring.

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  5. Wonderful post! Delightful to read and full of great observations. I was not familiar with E.O. Wilson, but will look up his writing. Thank you!

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  6. Wonderful observations, I do enjoy reading your posts :-)

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