Final answer:
The index of diversity of insects is higher in the hedge than in the barley field due to the presence of a greater variety of food sources and reduced pesticide use.
Step-by-step explanation:
The index of diversity of insects was higher in the hedge than in the barley field due to the presence of a greater variety of food sources and reduced pesticide use. In the hedge, there are more wild plants and trees, providing a diverse habitat and food sources for insects. On the other hand, the barley field is a monoculture, with only one type of plant, resulting in fewer food options for insects. Additionally, the use of pesticides in the barley field may have further reduced the diversity of insect species.