Leaf cutter ants are incredible. Every time we see their paths, a few inches wide, clear of vegetation and sometimes worn deep into the soil, populated with streams of workers carrying leaves back and heading out for more, it’s a little bit mind-expanding. While comparing such radically different kinds of organisms can be a bit problematic, the parallels with ourselves that can’t help coming to mind are so intriguing; some would say that it is hardly surprising that perhaps the most successful agricultural system in the world exists in an organism where the interests of the individual are entirely subsumed by the hierarchies of the state (http://environmentalhumanities.org/arch/vol1/EH1.9.pdf).
But apart from that, it is also incredible to realize that they are such major defoliators in tropical ecosystems. A few nights ago, Jake and I watched a stream of them harvesting the leaves of some kind of small bush. Their efficiency is remarkable. In just a few minutes, the number of leaves that were gone was noticeable in the overall contour of the bush. And of course, while leaf cutters might be the dominate defoliators, there are many many many more creatures’ mouths attacking leaves. The question of how plants survive such an onslaught is a recurring one in tropical ecology, and is one that has also vexed people who try to apply temperate-zone industrial agriculture in the tropics, often resulting in very very high levels of pesticide use, with all the associated implications for human and beyond human health.
Yet around the world in tropical places there are people who have been practicing subsistence horticulture for centuries, in sometimes remarkably stable and productive systems. How are they able to do this? What kind of techniques protect their plants from loss or, historically speaking, gave them enough of a margin of security as to be able to absorb some likely inevitable losses? There are plenty of answers that are easy to imagine. In particular, it seems plausible that, just as tropical trees grow in a highly diverse mosaic of species, tropical horticulture would historically have derived some protection simply through the diversity of species grown together. But that is conjecture on my part, and I’m curious to see how people are dealing with that particular problem when I’m back in a few months. How can leaf cutters and farmers share a landscape?