Fly-half Wakarua has been dropped from the starting line-up and will be replaced by De Marigny, who played at full-back against France.
"Rima Wakarua played against England and France and he did a few good things and a few not so good," said Bollesan.
"He will be replaced by Roland De Marigny - a player of the same standard. If you compare the two players, Wakarua has strengths and weaknesses. Against Scotland we need somebody who will play deep and Roland is better suited to doing this.
"But Rima will be ready to enter the action at any time, he is a loyal and professional man so I don't think it was difficult for him to accept the decision."