There need to be loads more bug Pokémon. There aren't any ant Pokémon, cockroach, fly or mosquito. We need lots more.
For an ant Pokémon it could start off as a larval, then if it's male and has a high attack or something it becomes a soldier ant, if it's male and has a high HP or something it becomes a worker ant. If the larval is female (which would be very rare, like female Combee) it would become a queen ant.