In Pokemon GO, Wurmple falls under a low populated category where one evolution of a Pokemon is a mystery or a gamble. They generally cost less candy to evolve at first, but getting both forms can prove a challenge if bad luck persists.
Wurmple is the first evolution before that mystery category. Once players decide to evolve a Wurmple, it can change into a Silcoon or a Cascoon. The evolution costs 12 candies and is entirely random, regardless of the sex of the Pokemon.
After evolution, there is still no difference in sex for Silcoon and Cascoon, unlike some Pokemon after they have a mystery evolution. However, the first evolution of Wurmple does matter a good deal after the fact. Both Silcoon and Cascoon evolve into separate Pokemon, and the process is guaranteed.
Silcoon is based around a butterfly, and the evolution is called Beautifly. Cascoon, on the other hand, is moth-based, and the final form is called Dustox. They are both considered different Pokemon, and gamers will need them to complete the Pokedex in that region.
To actually achieve the final evolution of Wurmple, players will need an additional 50 candy. In total, that's 62 candies to evolve from Wurmple to either a Silcoon or a Dustox. If players plan on getting both final evolutions, they'll need 124 candy if both forms evolve as desired.
Where to catch Wurmple in Pokemon
There is, unfortunately, no guaranteed way to get a Wurmple in Pokemon GO at the moment. But Pokemon GO is a continually changing game, and which Pokemon appear is essentially a flavor of the month.
One way to look for a Wurmple is to simply walk around in a region with nicer weather or when the seasons change to Spring and Summer. The region and current climate will decide which Pokemon spawn and Bug-types can be more common at warmer times.
Events are also something that will directly affect the spawn rate of a Wurmple in Pokemon GO. Wurmple is a Generation III Pokemon, which means that any events for that region will likely feature the Pokemon. Last year, there was also a Bug-type even where Wurmple was in abundance for days at a time.
It all comes down to playing Pokemon Go at the right time to catch enough Wurmple.