March Upcountry (Empire of Man Series #1)

Roger Ramius Sergei Chiang MacClintock is young, handsome, athletic, an excellent dresser, and third in line for the Throne of Man. But that's before his mother the Empress packs him off to a backwater planet, a saboteur tries to blow up his ship, and he finds himself shipwrecked on a jungle planet filled with damnbeasts, killerpillars, carnivorous plants, and barbarian hordes with really bad dispositions.