Tuesday, July 12, 2011

Ants Relocating

My work is often interrupted by the activities of some animal behaving in what I consider a strange manner. In this case, my trip into the barn in search of a tool was put on hold when I spotted an ant pupa and its accompanying workers. The large size and presence of wing pads indicated the pupa to be that of a queen ant. I find similar pupae regularly every year, so the encounter wasn’t unusual. What puzzled me was the reason for its being out in the open on my barn floor.

As I opened the door further, it became apparent that the pupa was not alone. Pupae were scattered about the floor in an area several feet wide.

The ants are a species of Crematogaster, a fairly common ant in most areas. They are known by their heart shaped abdomen, called a gaster, which is capable of delivering an irritating liquid from its tiny sting. These individuals are in their classic defense pose with jaws agape and sting aimed up.

These ants are clearly caring for the pupae. They were certainly quick to attack my little finger when it brushed the floor while I took this shot. The darkening of some of the pupae indicates that adults are nearly ready to emerge. A few winged males are already in evidence. But the question of why they’re scattered across the floor remains, at least until a rain of pupae falls on my head.

A look toward the ceiling answers my question. Crematogaster ants are known for carrying their pupae aloft prior to the emergence of adults. It’s not uncommon to find pupae in the mailbox or one of the bird boxes. In this case it seems that the ants are trying to squeeze the pupae into a tight spot beneath the boards of my barn ceiling. As additional ants pile on to the heap, the mass becomes unstable and clumps of ants and pupae fall to the barn floor.

The whole operation reminds me of a mountaineering expedition. The ants scale the vertical face with temporary encampments along the way.

At the bottom of the wall is the base camp. Pupae are piled in readiness for the trip up. The pupae from the floor were eventually moved into this position. While I was watching, I witnessed two ant avalanches. Those are tough little creatures to withstand that fall without injury. I wonder how many times they were carried aloft before their position was secured.

It seemed to take a standard squad of five workers to transport a queen pupa up the wall. In typical Three Stooges fashion, I saw a couple of instances where a worker actually stood on the pupa while pulling. The rest of the ants continued carrying their companion along with the pupa. Could there be such a thing as a lazy ant? When I came back a few hours later the floor and staging area were clear. Sometime in the next few days I’ll probably be able to witness the mating swarm depart.


  1. Oh my gosh! I've never seen so many pupae in my whole life. So.. the ants will continue relocating them to your ceiling and the pupae will keep falling to the barn floor, right?

  2. Hi Steve.Well that quite a creepy crawly post..
    Hey I know some people of thew Three Stooges type ..even been there myself..hahaha!!
    That is some load of ants and I am glad that that not the crew that is around my house!
    I sat and watched some black ants walk the length of the deck rail up a6ft. pole and across a 2ft bar to get to the hummingbird feeder and back...can't figure where the are going !!
    I finally put a sticky tape around the pole and that has detered them some...any suggestions ??

  3. Goodness. I'm not so sure I would want them to be so near and dear to where I want to be working, but I understand your need to allow them to do their own thing. Fascinating post. I always learn something here.

  4. never a dull moment at BJB!very interesting.

  5. Hi, Alexandra. I don't know how long it took, but the ants finally got all of the pupae tucked away so they wouldn't fall.

    Hi, grammie g. I once put that Tanglefoot goop around the hummer pole to keep the ants away and the ants responded by building a bridge of dirt and plant bits to make their way across. I stopped using the goop because I was afraid it would get on the birds.

    Hi, Lois. I'm used to working with insects and other animals sharing my space. Except for those that make their livings by biting mammals, they haven't given me any trouble.

    You're right, Michael. Someday I may experience this rarity known as the Dull Moment.

  6. Ants are Crematogaster cerasi. Neat account of their relocation behavior.