okayy, so it dont actually say no anywhere. but im guessing that since they can fight off bears, lions ect without feeling anything, that a little insect wouldnt sting them (:
They could be stung but they wouldn't feel anything and it wouldn't leave a mark. Its kind of like a くま, クマ can scratch them but it doesn't hurt them because ヴァンパイア and pretty much invinsible
