So, the idea was to have the Big Bugs attend the insect olimpics after you evolve them. That got cut, but I still had all the assets and a system to determine how the larva would evolve.
In the end I thought that explaining everything would only build false expectations as it's all setup with no punchline. So keeping the game nice and snappy became a priority. But if you are curious, diferent excersises will give you diferent bugs. Eg. If a bug is good at Weightlifting and good at Special it will turn into a demon fly.