Colony collapse disorder (CCD) is unexplained loss of entire bee colonies that has been occurring in increased numbers across the world. The cause of the disorder is unknown, although it has been suggested that pesticides may play a role. To study this phenomenon, 300 bee colonies at 20 different sites across the U. S. are analyzed. Colonies are classified as having no CCD symptoms (group 1) or as having CCD symptoms (group 2). Bee pollen is isolated from group 1 and group 2 colonies and analyzed for the presence of pesticides. Significantly higher average pesticide levels being found in group 2 colonies, the conclusion of the study states that increasing pesticides use may be leading to the death of bees and a loss of bee colonies in CCD. Does this study have a control group