There are many bats that live on the nectar from the flower of plants. There are some flowers that only bloom at night and the bat is the only animal that assists in the pollination of these plants. Cactus like the Agave are an example.
Bananas, avocados, dates, figs, peaches, mangoes, cloves, cashews, and agave are other trees that all benefit from bats as they pollinate or spread their seeds.
Bats will also eat bugs that destroy crops and plants.