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Catching grasshoppers!

A project log for Neuroscience of Grasshopper Jumps

Why are grasshoppers so hard to catch? Let's explore the visual neurons behind the grasshopper's escape mechanism!

Dieu My Nguyen 06/29/2016 at 02:440 Comments

I went out to the field in Ann Arbor, MI yesterday and in my mind, I wanted to catch at least 20 grasshoppers to last me about two weeks of data collection. After two hours of navigating through a vast tall grass field in the Nichols Arboretum in the scorching summer heat, I had to lower my expectation, to maybe about 1 little grasshopper in my cage and I'd happily go home.

The grasshopper's abilities to camouflage and escape are responsible for my wasted time. But I shouldn't think of it as wasted time! After all, I am studying one of the reasons why these bugs can escape dangerous predators, like myself who will make the grasshoppers watch circles expanding and contracting on the iPad screen.

Today, with practice and learning from the WikiHow article on how to catch grasshoppers, I became a capable predator. With one hand, I now can simply come from behind a grasshopper sitting on a leaf and enclose my hand with both leaf and grasshopper wiggling inside. They don't only struggle to escape from my hand, they also vomit a tobacco-colored bile as part of their escape mechanism after being caught. (So many escape methods! I study the mechanism they use to avoid being caught in the first place.) A paper studied this regurgitation behavior as the self-defense of the grasshoppers and found that the vomit can make lizards reject the grasshopper before complete ingestion. But the vomit might not protect the insect from vile humans, at least not when the human is me, determined to catch my study organisms despite the discolorations of my hands.

For a successful catch in a tall grass field, sweep through the field despite the itch and the thorns. Use both the central and peripheral visual fields. Spot the grasshoppers who blend in too well with the plants and ground (they come in many shapes and colors--mostly green and brown). And be decisive! Grab and pluck that leaf that the alien-eyed bug is sitting on. And ta-da! Happiness.

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