If your touch moths will they die?

They will only die if the wing membrane is damaged or torn due to the loss of protective scales (the dust that coats their wings). Moths can still survive if you touch them and remove some of their scales. Throughout their lives they naturally lose scales doing their everyday activities, yet this does not cause them to die. The scales protect the delicate membrane that makes up their wings, so if too much of them are removed (say if you rub the dust off their wings) they are more susceptible to wing damage, which would make them unable to fly, which would in turn cause them to die since they couldn't do what they need to survive.