What is your favorite clever/funny experimental design in ecology?

Imagine you’re a behavioral ecologist. You want to know how ants find their way back to the nest after foraging. One possibility is that they count their steps. How would you test that?

Why, you’d glue stilts to the ants’ legs, thereby lengthening their strides. If they’re counting their steps, they’ll overshoot the nest on the way back from foraging. Which is exactly what happens.

You’d also do some other experiments to test alternative hypotheses, of course. For instance, blindfolding ants to test whether they navigate by memorizing visual cues.

Those are pretty funny experiments. Putting ants on tiny stilts is just funny. Putting tiny blindfolds on ants is just funny. The stilt experiment is also very clever. The recipe for designing an experiment to test a mechanism is to mess with the mechanism, in such a way that the messed-up mechanism will fail in a predictable fashion. Ideally, you want to mess with the mechanism in such a way that you don’t mess with any other mechanism. That often takes cleverness. For instance, if ants are counting their steps, your first instinct might be to try to mess with their counting. But how would you make an ant miscount? I don’t think you can (can you?). So you have to figure out some other way to mess with their pedometer mechanism. You could move the nest while the ant is out foraging, so that an ant that’s counting its steps will either over- or undershoot the nest, depending on whether the nest has been moved closer or farther away. But moving the nest would mess with several mechanisms that ants might use to navigate. I think it would’ve taken me a long time to hit on the idea of putting ants on stilts, if I ever hit on it at all, so that just strikes me as tremendously clever.

This old post compiles a few other examples of study methods and experimental designs that seem very clever to Meghan and I. Using a CT scanner to reconstruct earthworm burrow systems. Using vibrators to mimic buzz pollination. Putting dung beetles in a planetarium to test whether they navigate by the Milky Way. Some of them are pretty funny too.

What are your favorite examples of clever or funny experimental designs in ecology?

15 thoughts on “What is your favorite clever/funny experimental design in ecology?

  1. This study confirmed that dung beetles used the milky way for navigation by setting up experimental treatments in a planetarium: https://www.sciencedirect.com/science/article/pii/S0960982212015072

    The authors incrementally removed stars and showed that these beetles rely on the whole milky way, rather than a few specific bright stars, to navigate. I think it is super creative, but the authors won an Ignobel Prize in Biology/Astronomy for this work…

  2. In the 1930s Niko Tinbergen studied how digger wasps find their way back to nests in sand dunes in Holland, where the nests are holes in the ground with side cells for individual offspring. Mom must make many trips away and back to provision the cells. tinbergen manipulated the landscape features to see what the wasps used to navigate, and also studied how they ‘learned’ the features for a new nest location. A hierarchy of clues were used, depending upon spatial scale, and several of his manipulations tricked the mothers into going/looking elsewhere. My favorite was to encircle a nest opening with pebbles during its construction but before the wasp had learned its location; the wasp then did some learning flights, and soon began foraging going out and coming back from far away. While she was away Tinbergen simply moved the ring of pebbles; yup, mom came back and went to the pebble circle and was surprized[ just kidding] when the center of it did not contain the nest opening. She soon began a PLAN B local search routine….
    European Ethologist did many clever field experiments like these.

  3. Sometimes an experiment is clever because it tests a fundamental theory, where the theory predicts something non-intuitive. sex ratio evolution theory has many such predictions, perhaps its central being that in a large pop the ESS ratio will be 1:1 AMONG THE VERY YOUNG, independent of survival to maturity. Furthermore the equilibrium 1:1 can be achieved in pretty much any genetical way ; XX,XY is the simplest, but any recurring mixture of genotypes that yields 1:1 will be ok.
    Basolo [Am Nat, 1994,144:373-390] and Conover[Science 250(4987) 1556-1558] used very different means to produce biased initial sex ratios [ in both directions] in fish and let selection go on for several generations. Natural Selection moved the pop sex ratios back to 1:1 after just a few generations. Many interesting details here; The genetical system used by Basolo was simple enough for her to predict the trajectories the genotypes should take on the way to 1:1…. theory worked just fine for the directional selection on the way to equilibrium.

  4. This is my favourite. It involves the training of bees. This experiment has been substantially duplicated under other conditions (eg., bees training other bees to play football), and the results may have applications when bees enter the general workforce, for example, in the garment or underground-mining industries:

    Researchers at Queen Mary University of London couldn’t get bumble bees to tug on a string attached to a hidden small disc of sugar water. They trained several bees by incrementally hiding the disc until they only way to access it was by pulling the string, which the bees did. Now, the fun part. Untrained bees of the same species were placed behind glass where they could watch their colleagues. They acquired the string-pulling skill by observing, not by training.
    “Associative Mechanisms Allow for Social Learning and Cultural Transmission of String Pulling in an Insect”, PLOS Biology 2016.

  5. A graduate student needed to track current flow in a coastal Atlantic area, but could not afford GPS devices. Instead, she tattooed a URL onto each of a large box of oranges and dropped them into the ocean upcurrent. People who found them visited the URL, which asked for the location where they were found; she successfully drew current maps from the resulting data. She was proud of the fact that oranges are fully biodegradable. (No cite, sorry, my memory for names is a sieve.)

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