Saturday, September 24, 2011

Citronella Ants Go Marching

Originally published, 2011. Edited and submitted to Simple Science Strategies September 2012 Blog Carnival.

When we moved into our 1896-built brick American Foursquare home in 2004, we discovered a pile of bricks in the basement. We also discovered a neglected backyard that looked like the jungle scenes in Predator: hibiscus hedges grown 10-feet high, bittersweet vines rambling over the tops of everything, moss growing beneath the undergrowth.

Being a gardener, I set out to turn our city yard into a little green corner of rest amid the parking lots and multifamily homes of our neighborhood. My husband provided the brawn and the hedge management, and I set about to restore the flower and vegetable gardens that my father-in-law had planted many years ago. And, being a nostalgic kind of girl, I grabbed bricks from that pile of leftover bricks from the house, to help define the edges of the beds.

One side benefit of this edging being everywhere is that it makes a ready-made exploration center for little boys (and their mom!). My son and his friends regularly spend mornings systematically turning over each brick, seeing what kind of interesting creatures they can find. One permanent resident of the brick edging in our yard is the citronella ant.

For our September study, we decided to modify the One Small Square activity a little, and we used each brick as an observation "square." We worked our way around one flower bed, noting all the organisms that we saw along the way, including our citronella ant friends. Instead of sketching in our nature journals, we photographed the things we saw, and reviewed the photographs later.

[Note: I have previously mentioned that my little guy, while he loves science and nature study, does not have the patience all the time to sit and observe quietly. So we are practicing sitting still and observing in small doses, but photographing what we observe allows us to also go back and "revisit" an observation at our leisure. This has been invaluable for us as we practice our skills of observation, and has also led to my son deciding to go back outside to the spot, to get more firsthand information. I've also used photojournaling as a learning strategy with kindergartners on nature hikes -- they move fast and miss things, and the photographs help jog their memories later.]

What is a Citronella Ant?

Lasius (Acanthomyops) claviger (
Citronella ants are a medium sized ant (smaller than carpenter ants, and larger than black or red ants), that can frequently be observed at this time of year, parading in a very long file from across the yard, sometimes up the side of a house or over a rock wall, as they move from a summer abode to a fall lodging. The first time I saw citronella ants, there was a line of thousands of them strolling between an old stump in the flower bed that we observed this month, across the yard and up the side of our house. Their size and color made me panic, as they resemble termites!

I looked them up on the Internet that year, and learned that, if you rub or squash a citronella ant, it gives off the odor of oranges, which gives it its name. So, much to my relief, a "field test" of this strategy showed me that we did not have an infested home, but a harmless wanderer in search of a winter cabin in the woodchips at the edge of the yard. Citronella ants are not a household pest -- they rarely move into homes for the winter, as other ants might, and do not come into homes to forage. They alarm people, usually in the fall, because they travel in a huge quantity for a few days, then they go back to their private habits again.

We have a large citronella ant colony that moves around one part of our yard -- we study them often.


Our Photo-Study of Citronella Ants
(all photos Kim Bennett/One Big Happy Family (c) 2011, except where otherwise noted)

A brick edge makes a great "small square"

Science Process Skill:

Method of Data Collection:

Materials Needed:
Digital camera
Clipboard and observation sheets (optional)

We took our camera outside, and began at one end of a flower bed, turning each brick as we went. Here are some of our more interesting observations from our modified "One Small Square" activity.


What evidence of ant activity can you see?

What do you look for when observing wildlife?

We can tell that a creature has been present in four different ways:

  • direct observation of the animal
  • tracks of the animal
  • scats left by the animal
  • other signs of the animal's presence
Here, we see lots of signs of ant presence (tunneling), but not many ants.

More signs of ant activity

What's a track, and what's a sign?

Sometimes, when we study larger animals, we see the actual impressions that their feet leave in the soil, mud, snow or creek bed. These are animal tracks, which tell us a lot about the size, activity and habits of the creature we are studying. You can learn more about animal tracks in "Follow Those Tracks!" 

Of course, when you study tiny creatures, such as ants, you will not see tracks. So you need to look for other evidence of their activity and movement, such as tunneling, body marks, claw scratches, gnawed wood, shed skin or tufts of hair. These other traces of the animal's presence are called signs. Ants leave lots of signs of their activity, and their tunnels are very interesting to study.

Who else lives here?
Learning from neighbors...

Sometimes, we come upon other living things in the vicinity of our target organism. All the creatures that inhabit a particular area are part of that area's ecosystem, which includes the living and non-living elements that exist in harmony with one another in a particular part of a habitat (See The Power of Observation: Life in a Tiny Ecosystem for a similar study of the life on, around and under a rotting log).

This white grub is the larval stage of a beetle (probably a June bug or rose chafer). It hangs out, eating plant roots. A few black ants are visible.

Direct observation of citronella ants
Direct Observation

What you are really hoping for when you set out to observe a living thing, is to actually see it with your own eyes (or at least your video equipment!). When this happens, you are making a direct observation of the organism -- you are not looking at tracks (footprints), scats (droppings), or other signs, but the actual creature of interest.

In this photo, we can directly observe another white grub, an earthworm, a centipede, and some citronella ants caring for eggs (at the center, right).


Did you know about...?

The next time you are exploring the life underneath a rock, log or other object, look for white, fuzzy or root-like material at the surface, just beneath the object that you turned over. Most people think this material is the root system of a plant, or is fungus. In actuality, this is a fungus-like organism in the group called actinomycetes. Actinomycetes are very fond of wood for food (in fact, fungus isn't very good at digesting the cellulose in wood, so any time wood rots, actinomycetes are involved). They are the organisms that give fall it's characteristic smell, and that let your nose know that it's going to rain (these critters love damp weather, and wet leaves or spring rain cause them to give off an odor that we all recognize).

The yellowish "blobs" in the photo are masses of actinomycete "bodies."

You will learn more about actinomycetes in another blog entry.

Citronella ants hard at work
Ants are social insects

One of the neat things about an ant study is you can learn more about the life of a social insect.  Social insects live in large groups, usually centered around one fertile female (the "queen"), with a number of workers (infertile females) and some males. Ants live in a social group called a colony. where individual ants all assume a particular role to keep the colony alive, protected and healthy.

Here, you can observe a group of ants entering and exiting from one entrance to the underground colony.

You can see this cooperation at work through a little experiment. When you find the entrance to a colony, gently cover the hole with some soil (it's ok -- ants have multiple entrances to their colony). Nearly immediately, you will observe the ants nearby stop what they were doing, and open the entrance again. Then they will get back to their original activity. Very cool.

Global Newt has a number of online games that are based on social insects (bees, ants and termites). Learn about life in one of these family groups as you play.

Ants communicate with one another
Communication in social insects

In the Arthurian tale, The Once and Future King, a young King Arthur (referred to as "Newt" by his mentor, Merlin the Magician) is turned into a number of different types of living things, so that he can gain wisdom from learning about their lifestyle. In one chapter, he becomes an ant (an experience he doesn't enjoy), and learns how ants communicate with one another.

If you observe citronella ants or any other ants, you will see that they approach one another very closely, and actually touch when they meet. You might even see them rub their antennae together, or exchange material mouth to mouth. Ants use their antennae to communicate information to one another, to recognize one another (so intruders are kept out of the colony), and to sense their atmosphere in other ways. Many types feed one another regurgitated food.

You can read more about the communication and behavior of ants at Ant Farms.

Winged ants

At this time of year, you might observe some of the ants in your area sporting a set of clear, long wings, as some in this photo have.

Sometimes an ant colony will grow too large, or will need to move. Some ants are raised in the colony which, unlike the workers, are able to reproduce. These include some females, and a lot of males. These winged ants reproduce and the females become new queens in new colonies. Winged ants are often seen late in the summer, as the colony prepares for wintering.  Once the ants get to their new home, the wings drop off.

The Colorado Cooperative Extension Service has an informative article on flying ants that explains more about this phase of a colony's life.

Enchanted Learning has over 300 separate items on ants, including diagrams, life cycle mini-books, and fables that can be used to supplement an ant study. Our ant study led into our mushroom study, which you will see in the next blog entry, so we did not spend as much time on notebooking with our ant study, as we have in the past with bird studies.

The Notebooking Treasury has a beautiful set of Nature Study Notebooking pages which we regularly use for documenting our nature study activities. This set includes generic observation pages, insect pages and diagrams, and pages for documenting the life in and around a log.

Check back soon for our next blog on mushrooms, fungus and the strange case of the "zombie ant".

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