To 1 gallon of R/O water I put 1ml (glass eyedropper full) of YG standard formula.
I also add a 1/4 - 1/2 strength orchid fertilizer for the macro nutrients (nitrogen, phosphate, potassium) and do a bi-weekly or monthly soil flush. If you don't want to use the macro nutrients you can leave the orchid fertilizer out, if you're feeding insects it really isn't necessary to use the macronutrients but I do anyway and see no bad effects from it.
I keep a seperate mister bottle full of this mix *for an occasional foliar mist maybe weekly or bi weekly whenever I think of it but I always remember to *mist off the plants with pure R/O the next day with another mister that is only used with pure R/O water-just to prevent any possible chance of a nutrient build up on the leaf surfaces.
I've never added fertilizer to the pitchers only crickets and fruitflies (when the plants were tiny). I once added bloodworms to the pitchers and it blackened them so ever since I'm a bit wary of adding anything too "rich" to the pitchers.