Biological control may be an emergent property, an ecosystem service, of a functionally diverse ecosystem. It has been shown that there are greater numbers of predators and parasitoids in more diverse systems but it has been difficult to demonstrate increases in biological control. It has also been shown that these systems can produce similar yields (in amount and quality) to chemically intensive low diversity agroecosystems. As an emergent property of the system it may not be possible to detect increased biological control through our traditional reductionist approaches to research.