Out with the old; In with the new! — Twig Ants

Elongate twig ants (Pseudomyrmex gracilis) carrying food to the nest.

More pictures from the Pseudomyrmex colony that nested in my window lining last spring.  The workers above posed nicely on the window glass as they all tugged on a bit of food.  Normally the workers of  Pseudomyrmex colonies tend to forage independently, relying on their speed, size, and potent sting to bring down prey and haul it back to the nest alone.  However, in this case, the haul in question apparently attracted the attention of some other workers.  People tend to think of ant colonies as perfectly synchronized machines, operating in perfect unity.  However, anyone who has actually watched a group of ants attempt to maneuver a large prey item down a small nest entrance will have noticed that it’s more like a game of tug-of-war, with hopefully most of the pieces deciding to pull in the appropriate direction.  The same sort of ‘rule-by-majority’ principle applies to any number of colony processes, such as selection of a nest site.  I have personally watched a group of acrobat ant workers purposefully hauling larvae to a new nest location, while a second group of workers diligently hauls them right back, passing each other on the way.  They’ll also drag the queen along if she doesn’t cooperate.

A twig ant worker (Pseudomyrmex) removing trash from windowsill nest.

In the Life of an Ant

Elongate twig ants (Pseudomyrmex gracilis) nesting in a windowsill

Last spring I had the pleasure and entertainment of some of my favorite ants setting up camp in the exterior lining of my front window.  Pseudomyrmex is one of the groups of ants that truly displays the close relationship to wasps in their form.  I have never been stung, but I’m told it’s fairly painful.  Luckily, like many insects, they are not particularly aggressive towards humans unless truly provoked.  In general these ants responded to my getting too close with the camera by dropping off the wall to the ground, a fairly common escape behavior.  It was fun to watch the workers as they hauled home their catches and try to identify the prey item.

A twig ant (Pseudomyrmex) preys on a plant bug (Miridae).

Mirids (Miridae), commonly(and rather vaguely) known as ‘plant bugs’ were all over the place at the time, and seemed to be a fairly common catch.  My personal favorite was the small critter seen below, whose large curved jaws identify it as a neuropteran larvae, one of the net-winged insects.  It’s likely a lacewing larvae, but–as a number of antlions had set up pits in the sand below the window–I am personally fond of the idea that this is a case of ant eating antlion.  Sweet revenge!

A twig ant returning to the nest with its neuropteran prey.