ABSTRACT
Flowering plants and their insect pollinators evolved during the same period, the Cretaceous (Table 2.1A). During prehistory and most of the historical period, sufficient pollinating insects were generally present to pollinate crops grown by man, and with a few exceptions no special attention to the process was needed. But by the late 1800s and early 1900s a single crop (monoculture) was grown on larger plots of cultivated land, as in Figure 45.5a. Yields from certain crops proved to be unsatisfactory in some areas , and investigations showed that this was due to insufficient insect pollination. Also, some varieties of fruit were self-sterile, and a tree did not set fruit unless a tree of a compatible variety was planted nearby and insect pollinators were present to transfer the pollen.
