Good Vibrations

Over that supper we had the other night, Pinkie, Spike and Rarity got to discussing rock culture. Rarity was interested in knowing why there are so many big and beautiful gems in the bat cave she has been spelunking (while trying valiantly to avoid getting covered in bat guano). Pinkie is mostly familiar with open-air rock farming and bat-free grottoes, but she and Spike were in agreement that a combination of the acoustics in the cave and the ultrasonic squeaks of the bats probably augmented the growth of the gems that were naturally there. Together they came up with the suggestion that Rarity should plant gem grit in the cave, thus seeding it for future gem crops. Fluttershy weighed in that they should also make sure that their bat population is stable and sustainable in the long term. She's going to go with Rarity next time to see the cave and survey the bats on their way out, with the goal of finding out which ecosystems they're exploiting.