It's OK, space has too much radiation for things to migrate off world unshielded. Except if you are a tardigrade though, but the reasons for them being like that are due to the types of niches they occupy on earth. Mosquitos on earth that have some sort of space proof shielding in their exoskeleton would probably be quickly outcompeted by those more fit mosquitos that don't have to invest resources into this space proof exoskeleton.