How do leafcutter ants cut leaves off of trees? #TeamTrees

About 50 million years ago, a group of ants started doing something that only three other types of animals, including humans, ever have. They started growing their own food. And about 40 million years after that, some of these fungus-farming ants started growing their underground fungus gardens by feeding them leaves that they collected by doing this. Recently I was given this colony of leafcutter ants, Atta cephalotes, and these are some of the most interesting and, actually, most well studied ants on earth. I don't currently have any research projects on these, but if there's one thing I'm interested in, in science, it's fine scale details of animal behavior. So, i've been filming one tiny little aspect of what they do throughout their lives and that's how they actually cut leaves off of trees. In a day a mature leafcutter ant nest can cut and gather hundreds of thousands of leaf fragments. Once an ant finds a suitable leaf and begins cutting it can recruit its nestmates to the leaf with a vibrational signal. It makes this signal by rapidly raising and lowering its abdomen while cutting the leaf. Sending vibrations through the jaws into the leaf and down the stem to nearby nestmates. The ant does this by moving its abdomen at this point here, scraping the series of microscopic grooves called stridulatory organ and producing a series of chirps at a frequency of one kilohertz. Leaf cutting isn't the only time these ants stridulate though. What you're hearing now are recordings made during digging, which is another context where stridulation also works as a short-range recruitment signal. During leaf cutting these chirps vibrate the mandible while it cuts. By vibrating the mandibles and by using the front foot to pull up on the leaf edge, cutting workers actively stiffen the leaf so they can make a smooth, easy cut. Ants cut semicircular wedges out of the leaves by anchoring their legs on the edges and surface while rotating their bodies during cutting. Slicing through a leaf involves piercing with a leading mandible and pulling a fixed cutting mandible through the leaf. Either mandible can function in either role, slicing through the leaf or advancing the path of the cut. Watching this happen from below, the cutting mandible slices and tears through the leaf as the ant uses the bite of the other jaw to pull it along. All of this is powered by massive muscles connecting to the jaws that account for 50% of the weight of the head and 25% of the ant's total body mass. All of this leaf cutting is just the first step in feeding a living garden of fungus found inside the nest. A garden that is continually grown over a decade or more of a colony's life, supporting one of the most advanced animal societies on earth. So, cutting leaves off trees is a tiny little fraction of what these ants do. There's so many more details. I mean even before that leaf fragment is fed to the fungus there's another round of cutting and cleaning that happens inside the nest. So this video has been all about ants that make their living from trees, and trees are pretty important to us too. And you might already know that across YouTube right now there's a campaign called #teamtrees which is calling for people to support forest restoration efforts by donating to the Arbor Day Foundation. I think this is a great idea and a way we can all do something to support healthy forest ecosystems across the world. So what I'm doing is I'm gonna donate 100%, all of the lifetime ad revenue that's ever been generated by this channel. Which happens to be a hundred and seventy eight dollars. And I'm gonna do that through teamtrees.org. I think it's only appropriate to give whatever this channel has made back to an organization that supports the natural world. So I encourage you to go to teamtrees.org and make your donation yourself today.

Channel: Ant Lab

Views: 41,531

Rating: 4.970191 out of 5

Keywords: leafcutter ants, leaf-cutter ants, leaf-cutter, leafcutter, atta, atta ants, parasol ants, fungus farming ants, ant agriculture, ant fungus, atta cephalotes, tropical leaf cutting, tropical ant leaves, ants carrying leaves, ants cutting leaves, #teamtrees, teamtrees, ant symbiosis, cutting leaves, leaf clipping, leaf harvesting, fungus farming, acromyrmex, fungus-farming ants, adrian smith ants, ant lab, antlab, dr adrian smith, north carolina museum, ncmns, entomology

Id: yqdD4lc20Wk

Length: 4min 46sec (286 seconds)

Published: Tue Nov 05 2019