It all starts with drinking a bit too much water and having a tolerance for ants crawling all over you.
I once read a study about leaf cutter ants discussing how important they are to rainforest ecosystems in terms of the sheer quantity of leaves they eat- researchers found they can eat around 15% of leaves in the forest, which is really a huge chunk of all of the green stuff out there (Costa et al., 2008).
However interesting the results, I thought the methods stood out even more as being quite entertaining:
“We then placed fragments of plastic sheeting (1 cm2; 0.1 mm thick) coated
with a solution of human urine and water (1:1) as an attractant on all foraging trails.”
No doubt about it, they peed in a cup, mixed it with water, and dipped bits of plastic in it, all in the name of science. You see, the minerals in urine (especially sodium) are really quite rare in the Amazon, and are much desired by all sorts of animals, not just ants. So apparently, you can even pee on a bit of plastic (a far cry from a leaf) and the ants will still take that back to their nest.
Afterwards, I saw this awesome video of ants ‘protesting’ pesticide use, it is hilarious and I recommend checking it out. I’m unsure if they used the urine technique or another, but I loved it. So, I figured I should give this a shot and see if we can use this Amazon sodium-deficiency to our advantage.
With the help of Destin from Smarter Every Day, we set out on a Peruvian Amazon night. We headed to one of the largest leaf cutter ant nests I’ve seen, which was easily 20 ft across with superhighways of millions of ants leading from it, especially at night. Prepping by drinking too much water that day, I delivered my ‘mineral-rich yellow liquid’ onto a large leaf nearby.
Then, I ripped small pieces of paper of various sizes with TheRevScience (and Smarter Every Day for Destin) written on it and dabbed them lightly into the urine. From there, we put those pieces into the trail of ants, and let them get to work. They quickly took to the tiny signs, but it seemed too many went to it at once. The larger signs got ripped into smaller bits, so we let those go. So we eventually made the signs smaller, the perfect size seemed to be about 0.5cm x 1.5cm.
The tricky part was getting the ants to pick up the sign in the correct orientation, and to get only one ant to be holding it at a time. This required a lot of picking the ants off the signs, placing it back down, and hoping they would finally get it right… which they eventually did (ants aren’t great readers).
We got bit by countless ants and mosquitoes while sitting still with the camera and light, and I shook out about a dozen ants from my pants upon returning to the lodge.
For the final touch, I added a music track I wrote and recorded for the video and stuck it on with the bumbling leaf cutters. All in all, a successful venture, and I like ants!
Costa, A. N., Vasconcelos, H. L., Vieira-Neto, E. H.M. and Bruna, E. M. (2008), Do herbivores exert top-down effects in Neotropical savannas? Estimates of biomass consumption by leaf-cutter ants. Journal of Vegetation Science, 19: 849–854. doi: 10.3170/2008-8-18461