Ant biology: October 2012 Archives

Hi!

I am Natalie, I'm in 8th grade in chicago and i Am doing science fair, I am putting ibuprofen in ants food and drink. My question is: Will trace amounts of ibuprofen affect the behavioral patterns of red harvester ants? I have both on my ant farms set up, and 15 ants in each, I just would like some help along the way so i can do a great science fair!

Thanks and hope to hear from you soon.
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Dear Natalie,

We are glad to hear that you are participating in a science fair and that you are planning to include ants in your experiment. Regarding the experiment you are planning to conduct, here are a few things to consider:

- How will you measure the behavioral patterns of the ants to see if they are different? There are many ways to do this, but you will want to come up with some way to standardize your measurements. Will it be how much food they consume and how will you determine this? How often the ants are active versus not moving for specific periods of time that you are watching them? How often do the ants engage in different behaviors between the treatments (grooming themselves, grooming other ants, etc.)? There are lots of observations you could make, just be sure to decide ahead of time what you will do. One idea might be to just spend some time watching your ants before starting the experiments to get ideas.
- To insure that you are measuring the effect of the ibuprofen, you will need to have a "control", which in your case would be a group of ants that you are not feeding ibuprofen, but otherwise are treated and fed exactly the same. This will allow you to determine if the ibuprofen is what is causing the differences.
- You would ideally also like to have multiple pairs of ants that are and are not fed ibuprofen (but I realize this may not be possible for your project this year).

We hope this helps and have fun watching your harvester ants! Harvester ants from the genus Pogonomyrmex are beautiful animals (to see what they look like up close click here).

Enjoy,
Corrie Moreau & the AntAsk Team


Thanks for your question, Nathalie!

It is true that ants are proportionately much stronger than we are. I don't think any human could dangle from the ceiling with 100 times his or her body weight, like the weaver ant Oecophylla pictured here. There are many adaptations that are working together to allow ants to perform impressive feats like these: hairs on their feet that can stick to very smooth surfaces, large muscles in their heads to close their jaws, and light lean bodies. Most worker ants don't have functional reproductive systems, so their strength-to-weight ratios are higher than many other insects that are weighed down with the burden of perpetuating their genes.

However, comparing the proportional strength of even the strongest humans to an ant is unfair. Even lions, tigers, and bears (oh my!) can't lift more than 10 times their own body weight, as many insects can. Some of the physics behind this is explained here. The strength of ants is "super," but it is not super-natural. It all makes sense once you know a little more about physics.

Briefly, smaller organisms will always have bigger strength-to-weight ratios, because it's the surface area of the muscle cross section that determines strength, but the volume of the animal that (all else being equal) determines mass.

Less briefly: imagine three perfect cubes, each of a different length: 2cm, 5cm, and 10cm. The 2cm cube has a cross-sectional area of 2x2=4cm^2 and a volume of 2x2x2=8cm^3. The 5cm cube has a cross-sectional area of 5x5=25, and volume of 5x5x5=125, and the 10cm cube has cross-sectional area of 10x10=100 and 10x10x10=1000. If these cubes were animals (admittedly, very strange ones), the 2cm cube could have a strength-to-weight ratio that was proportional to 4/8, while the 5cm animal's strength to weight ratio would be 25/125 = 1/5, and the largest, 10cm cube-animal would have a strength-to-weight ratio of 10/1000 = 1/100. Of course, this is an oversimplification, but I hope this helps clarify why all of the proportionately strongest animals are very small.

Although this is an ant blog, I feel it is only fair to point out that ants are not the strongest insect, even proportionately to their body weight. The prize goes to a dung beetle, which can drag more than 1000 times its body weight. These beetles are larger than any ant, which makes their strength-to-weight ratio even more impressive.

The feat of strength in which ants have beetles beat is how rapidly some of them can close their jaws. Ants of the genus Odontomachus can close their jaws at speeds of up to 230 km/hr (143mph), generating a force that is 500 times their body mass. Not only are these forces very effective at subduing prey and smaller enemies, some of them can use their jaws to launch themselves into the air. This youtube video is completely worth checking out if you like wathching slow-motion ants flail through the air. For a more dignified synopsis, one of the original articles on Odontomachus jaws is here.

I hope this helps!
best,
Jesse Czekanski-Moir & the AntAsk Team

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