Ants in the Mail

After 30 years of using the same mailbox, suddenly over 24 hours these ants and pupae appeared.  One day no ants, next day filled. The box is in a brick structure with a board on the base of the box which has been slowly disintegrating over the years. It had been raining heavily daily x 3 but the box and inside structure was dry. There were no ants on the outside.


Curious to learn more, I sent the pictures to my myrmecologist* James Trager who promptly sent me this reply. "Every spring, these same ants - Tapinoma sessile or Odorous House Ants show up in the mailbox, in stacks of flower pots and various other places up off the wet, cool ground, in order to incubate their brood. "

Our ants closeup -  REK

The Odorous House Ants, Tapinoma sessile, act like they have had way too much sugar, and indeed they have.  Their primary food in nature is honey dew, the sugary liquid produced by scale insects and aphids as well as plant nectar.  When humans came along they found another source of "honey dew," in kitchens and garbage.   Just like squirrels, crickets and mice, they liked what they found and moved in with us.  They will also eat dead insects when available.

   T. sessile -  Tom Murray

Dr. Eleanor** describes the species in her own colorful way.  Rather than biting to defend themselves, they run around erratically, spraying a defensive odorous fluid from their anal glands.  She describes the odor of a squished ant as smelling like blue cheese.  Fortunately I had sprayed them first and thus didn't chance ruining my taste for salad dressing.

Odorous house ants have a habit of moving their nest every few weeks which may account for how they showed up overnight in our mailbox.

* Word for the day - myrmecology - the scientific study of ants.  James Trager is a member of the AskAnt Team.  They answer questions on an interesting blog at antweb.org/antblog/.
** If you are yearning to learn more about ants or even become an amateur myrmecologist, a great free I-book, Dr. Eleanor’s Book of Common Ants
is available on line here. 
More detailed information on T. sessile is available at this link.