Ant Nests

Remember that  Pogonomyrmex nest with the shiny black spots around the nest entrances from a few weeks back?

 

black-spots-another-view

This one?

Upon revisiting a few weeks later, the ants are looking better.

Pogos-previously-with-black-spots

They seem to have cleaned up nicely.

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Maybe there are a few spots left, but nothing like before.

pogos-gathering-food

What are they harvesting today? You probably recognize the beetle elytra, but what is the gray cylinder?

pogos-with-screwbean-mesquite

You might need to be from Arizona to recognize it. That is part of a seed pod from a tree with the common name "screwbean mesquite."

Wonder what they will be up to next time I visit.

What kind of ants do you visit regularly?

While visiting a local park this week, I stopped by to visit a Pogonomyrmex nest I have been watching over the years.

black-spots-around-harvester-ant-nest

I almost immediately noticed the black spots around the nest entrances.

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Here's another entrance about 20 inches from the first two. There was a noticeable blackening around the hole in comparison to the surroundings. Otherwise, the ants seemed to be active and doing fine.

black-spots-another-view

This is a closer view.

black-spots-close-up

Looks kind of shiny.

My first thought was ant feces. Studies have shown that some ants mark their nest areas with feces, for example a study by Grasso et al. (2005).

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My other guess is that someone tried pouring something into the nest (as it is a public place.)

What do you think? Have you seen this before?

Grasso, D. A., Sledge, M. F., LE Moli, F., Mori, A., and Turillazzi, S. 2005. Nest-area marking with faeces: a chemical
signature that allows colony-level recognition in seed harvesting ants (Hymenoptera, Formicidae). Insectes Sociaux 52:36–44. (.pdf available for viewing)

4 Comments

In a recent trip to western New York, I noticed a trend. Whenever I found an ant colony (flipping rocks looking for bait for a family member who likes to fish)...

cornfield-ants

an ant colony like these cornfield ants...

cornfield-nearby-thief-ant

I found thief ants.

thief-and-crematogaster

Everywhere.

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Take these Lasius.

 

lasius-claviger-group-2

Can you see the thief ants?

lsius-claviger-group-4

Let me give you clues. The thief ant is in the top right of first photo, near cluster of three larvae in second photo, and going into the tunnel just left of center in the last photograph.

Thief ants are named for their tendency to live with or near other ant colonies and then steal food from their "hosts."

They can also be found living in separate colonies.

colony-of-thief-ants

Some of the thief ant colonies I found living by themselves were quite large.

 

thief-ant-large-single-colony-close

Looks like quite a few new thief ants are on the way.

According to School of Ants, thief ants are distributed throughout the United States (although they don't show any records for New York State on the map). I had never noticed thief ants when I looked for ant colonies in that location in the past. I know my vision hasn't gotten any better, so that isn't it. It seems like thief ants have gotten a lot more numerous there.

Have you noticed more colonies of thief ants where you study ants? Do you think this a trend or a random happenstance?

 

4 Comments

We have a question for the Consult-Ant today:

Hello

I have an ant question!

Over the years I have seen an unusual type of ant mound. It is a long, linear "mound"; actually a series of small mounds connected by tunnels of soil particles. The unusual thing about them is that extend in a straight line for several feet. Somewhere I heard these called "railroad ants", but I don't know if that is more than just a local name or description of the straight-as-a-string nest mound. I'd appreciate any information you might have about them, like scientific name or a reference where I could learn more. Thanks.

Dale

Dale,

Since you don't tell me where you are from, I'm going to take a wild guess and suggest you might possibly be talking about a type of fire ant. Fire ants tend to build loose mounds that are sometimes long and narrow. (Except if they were fire ants, you'd probably know about them already).

Does the mound you are seeing look like the second photograph in this post?

If not, please let me know where you are located, which will help me narrow the choices. Also, roughly how big are the structures?

Anyone out there heard this common name and know more about it? Please let us know if you have some ideas.

(Note: As I mentioned previously, I have been the “Consult-Ant” on the Leaping from the Box website. I answer questions about ants and ant farms. From now on I will post the answers here, and when Karen has time she will also post the answers on her site.)