It Won't Work if the Body and Legs Don't Cooperate
On MasterChef and other shows when the competitors are put together in teams this happens a lot. You'll watch as the egos of a few of the team members bring down the entire team. Someone on the team believes that he or she can do it all, and what winds up happening is the person either doesn't delegate enough of the tasks to other members or doesn't communicate well enough with other team members. While sometimes this is the team leader, it can also be a team member who takes on more than he or she can handle.
In a recent episode of said show, one of the contestants brought her team down by failing to communicate with the team that making dessert was not something she was comfortable with. She wound up struggling, and didn't communicate this until the very end of the challenge.
Communication is the glue that holds your project together. If you're the project manager, it is vital that you understand the importance of solid team communication. Listen to your team. Delegate tasks appropriately. If Ashley says she is not comfortable taking on tasks x, y, and z, then don't delegate those tasks to her. It's that simple.
Likewise, encourage all team members to raise their concerns. Do not encourage a culture where your team members are afraid to voice their concerns. Otherwise, you could find yourself in a situation where people are struggling and not saying anything until a minor problem becomes a crisis. Be diligent about checking in with team members as to the status of their projects.