Sure can. I have heard that ants are a huge problem in the cars. We made sure to vacuum our car before we left WDW (however DD got many more on the floor). We didn't have any ants, but check out the Cruise Line board.
We've never had a problem with ants. Last Nov we parked our car at the Radisson where we stayed the night before our Carnival cruise and took their shuttle to the ship. This Nov we're staying at the Radisson again, but driving and parking at the pier.