Where do you get thunderbugs in Monster Hunter Tri

Pretty much any where you find bugs you can catch thunderbugs. they are sort of rare so you'll probably need to find several bug gathering areas. Butterflies or fireflies mark the areas for gathering bugs. You also must have a bug net to catch bugs.

Make leather armor and equip it with gathering gems and whim gems. Now you get double the items at each gathering spot, you gather quicker and your bugnet/pickaxe will hardly ever break. Now take 5 mega/normal/old bugnets to sandy plains or volcanoe.