NPR on how the best fighters climb the ranks to reach televised glory:
Here's how the game works. Two crickets — always males — are weighed to the closest hundredth of a gram and then paired off by weight class like prizefighters. They are placed in a clear plastic ring nearly the size of a dinner plate, with a dividing wall separating the two insects. A referee signals go time, then slides out the ring divider to let the bugs face off.
The owners poke a special reed in to lightly brush their crickets, which goads them into fighting. The critters lunge and swipe their pincer-like mandibles at each other. A referee closely monitors the tiny combatants, noting the number of attacks and retreats.
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They are precious enough that their owners never let them fight to the death, and injuries are rare.
Vice posted a documentary a few years ago: