Sci-Fi Wire have posted a small article on the creature effects in Alien vs Predator. Here’s a paragraph:
“Though Gillis and Woodruff indicated that AVP will utilize computer-generated effects, they also noted that the film will retain the same visceral edge as its predecessors. “The first couple of movies [there] was basically a guy in a suit,” said Woodruff, who wore alien suits in Alien 3 and Alien Resurrection and plays the lead alien in AVP. “Now, on this film, we have more opportunities to do more with facial hydraulics as well as a completely hydraulic version of the alien.”
One more thing .... A praetorian alien came out in the comic books and games as said above, and is a special alien form designed to be a guardian for the queen. The word praetorian comes from an ancient Roman word. Praetorians in ancient Rome were special guards of the Emperors or Ceasars, thus the praetorian alien is a special guardian for the queen alien and her brood.