Ants and Dragonflies

 

The year is full of seasonal events.  Some I like and some I don’t.  As I was heading home yesterday evening, the road through our nearest town was closed in preparation for the annual fall street fair.  That’s one of those events I don’t like.  When I finally pulled into my driveway, I saw a large dragonfly swarm circling the Prairie Garden.  I always enjoy the fall swarms of dragonflies and this one was partly created by another of my favorite events.  Ants were swarming.

Ants taking off on their mating flight remind me of chumming the water for sharks.  Dragonflies come from all directions to feed on the ants.  This is usually an evening event and the lowering sun lights up both ants and dragonflies.  Unfortunately, it’s almost impossible for me to capture a photo that comes close to illustrating the beauty of the interaction between these two insects.  Nobody would guess that this photo contained a couple dozen flying ants and four dragonflies.

Occasionally I’ll capture an image that is recognizable as a dragonfly.  They all appeared to be Common Green Darners.

Other photos seem more suited to proving the existence of pixies or tiny x-winged fighters cruising above the fields of Blue Jay Barrens.

The dragonflies seemed to be targeting the large queen ants.  The queen’s flight was rather slow and there was a good bet that a dragonfly would nab her before she topped an altitude of 12 feet.  I think I just caught the tail end of the swarming event.  I probably would have been home in time to see the entire swarm if I hadn't had to detour around town.  During the peek of the swarm there would have been far too many ants in the air for the dragonflies to have caused much damage.  Those last few ants would have been trying to survive a sky full of predators.

The ants attempt to reach a high point, such as the tip of a blade of grass, before launching into the air.  This queen kept running up the grass blade and plummeting from the tip back down to the ground.  That’s probably why she’s one of the last to take to the air.  Maybe it’s best for her to be eaten, so she doesn’t pass on those bad swarming traits.

The workers and winged males were very small.  I had to crawl with my face almost to the ground in order to find them.  During the search, the neighbors drove past the house.  They just waved.  I guess my behavior no longer strikes them as being odd.

Amidst all of the workers was one that carried an ant cocoon in its jaws.  I guess being late hatching doesn’t excuse you from swarming.

Almost UFO's

I call these almost UFO’s because I know what they are and some people could probably figure it out from the photo. The yard was aswarm with dragonflies grabbing ascending winged ants rising from the lawn and I was futilely trying to capture the event. Even if I did get a clear image, it’s impossible to capture the beauty of a dragonfly swarm glittering in the setting sun.

The dragonflies were quick to take advantage of the ant exodus. The departure of reproductive individuals from an ant colony is a short duration event. More ants in the air means fewer total victims of predation. The timing also makes it less likely that predators will be able to accumulate in large numbers quickly enough to be a major threat to the ants. I observed both queen ants and the smaller males heading into the air. From what I could see, the dragonflies targeted the queens. Queen ants must be packed with nutrients because I’ve never seen a predator pass up a queen.

The dragonflies all appeared to be Common Green Darners. As the days shorten, dragonfly swarms will become increasingly common. This was a small swarm of around a dozen individuals. I’ve seen September swarms that contained hundreds of dragonflies.

By the time I turned my attention to the ants, the queens had all departed. The males were still launching at a fairly steady rate.

The males will catch up to the females and mate in the air. Other colonies of the same species are probably launching at the same time. As I watched, the workers and remaining males suddenly headed down the grass stalks and returned underground. There’s a good chance that they’ll be back at it tomorrow evening.