Animal Architects: Don’t Forget Ants

When we are not doing experiments, my son and I have been reading Animal Architects: Building and the Evolution of Intelligence by James R. Gould and Carol Grant Gould. animal-architects

We have enjoyed the book so far. It is not an easy read, but the stories of the different animals are fascinating. The book is much more than a review of animal construction techniques, it is how different behaviors reflect an animal’s cognitive abilities. It also reveals how researchers interested in cognition measure an animal’s potential.

The only point that has disappointed us has been the relatively thin coverage of ant architecture. Aside from a brief overview of the nests of army and weaver ants, the Goulds pretty much skip the ants, giving the excuse that what ants do is mostly underground and hard to study.

If you are interested in animal architecture, there are ant nests that do deserve attention. Take a look, for example, at this leafcutter ant nest. It definitely rivals that of the fungus-growing termites in its complexity and size.

Another excellent example of elaborate engineering by ants is found in Holldobler and Wilson’s Superorganism book on pages 338-339. Harpegnathus saltator ants build a nest that comes complete with “wallpaper,” and is thought to withstand flooding that occurs during the monsoon season.

Ants are also capable of making decisions about potential new nests sites, a similar issue that faces honey bees when swarming. The nest emigrations of tiny acorn ants of the genus Temnothorax have been studied extensively. Evidence suggests that scout ants investigating potential new nest sites actually have a way to “measure” the interior of a cavity to determine if it is suitable.

Here’s an example experimental set up:

temnothorax

And finally, check out Alex Wild’s wonderful photographs of examples of ant architecture.

What do you think? Are ants capable of intricate architecture?

Harvester Ant Mounds II

While observing the Messor Pogonomyrmex rugosus nest last week, I noticed one ant working on a seedling that was in a patch of other small plants to one side of the mound. (These are mostly Pectocarya – combseed).

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The worker ant seemed to be using its mandibles on the base of the plant.

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Of course, Messor worker ants clear plants from the area around the mound.

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It makes sense to prevent plants from shading the mound too much. Ants are known to regulate the temperature within the nest via mound architecture.

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Wish I had more time to spend observing this activity.

Do you have any ideas what this ant is doing?

Harvester Ant Nest Midden

During a quick hike through South Mountain Park in Phoenix, Arizona yesterday, I spotted a Messor Pogonomyrmex rugosus harvester ant mound.

messor-nest

The refuse or midden pile was covered with a fluffy material.

chaff-messor-nest

The ants apparently have been collecting the seeds of this plant, and discarding the seed coats.

creosote

It is a common plant in the Sonoran desert. Do you know what it is?

creosote-with-bee

The plant is a food source to a range of insects as well as Messor harvester ants, including more than 20 species of bees.

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It is the common creosote bush, Larrea tridentata.

The midden piles of harvester ants, as with many other types of ants, are known to improve the nutrient levels in the soil in the immediate area.

Tomorrow I will post more about Messor harvester ants.

Hum, now that I think about it, I wonder if “midden piles” is redundant, because midden is a trash heap. Anyone out there help me out on this?

Edit:  Thanks to Alex Wild for pointing out that these ants were Pogonomyrmex rugosus, not Messor.

Edit: Here’s a photo of Pogonomyrmex rugosus.

For more information, try:

Desert Harvester Ant, Messor pergandei

Dale Ward has some videos of Messor pergandei in action, as well as more information

More about cresote bush and the Zygophyllaceae (caltrop family) at the Arizona-Sonora Desert Museum

Ant Structures With GPS Addresses

Foresters are set to log the ancient Holystone Forest, in Northumberland, England. But first they need to locate and save a few homes located in the forest. Are these structures human dwellings? No, they are giant ant mounds.

The northern, or hairy wood ants  (Formica lugubris) build towering mounds out of pine needles, from three to seven feet tall. The nests act as solar collectors and heaters, allowing wood ants to live in places too cold for most other ants. In addition, the large black and red workers sometimes bask in the sun to warm up and then move underground to act as living heat radiators.

wood-ant-mound
Smaller wood ant mound from Switzerland

The hairy wood ants that build the mounds are now endangered, and every effort is being to made to protect them. Naturalists located of 69 mounds, which they mapped and gave GPS coordinates. Hopefully, the maps will help the loggers avoid getting too close.

For photographs and more information, see:
Guardian.co.uk has a story: Giant ants’ nests given special building protection

York Dales Country News story:  GPS used to protect ant ‘skyscrapers’

For photos and more information, see BBC – Potter ponders giant anthill

Edit:  And for children, see The Ant’s Nest book review at Simply Science.