Iowa Code § 621.6: Additional security.

In an action in which a bond for costs has been given, the defendant may, at any time before trial, make a motion for additional security, and if on such motion the court is satisfied that the surety in the plaintiff’s bond has removed from the state, or it is not sufficient for the amount thereof, it may dismiss the action unless, in a reasonable time to be fixed by the court, sufficient security is given by the plaintiff.