In the scene where Bud and Doyle are in the rain forest with the flowers and leaves in their hair, you see that Bud has turned his plaid pants into cut-offs. Then two scenes later in the bug laboratory, Bud's pants are back to their full length. Later on when they are playing golf with the billy goat, he's wearing cut-offs. Two scenes later when they are putting up the fly paper, he has pants again!