There are many different ways in which a plant can pollinate:
Blueberries are called buzz pollinated crops. They need a bee to do high frequency buzzing to release the pollen from the anthers.
In the central valley of california in late march, 70% of the world's almonds are in bloom and produced. 1.7 million honeybee colonies (most of the ones in the US) are trucked in to california to help pollinate these crops. As the honeybee has issues, so do the almond crops.
Squash have both male and female flowers and the pollen needs to travel between these two flowers in order for the plant to produce.
Any monocots/grasses do not need pollinators as they are wind pollinated.
Chocolate is pollinated by the tiny midge fly. Since midge flies like to be in the rainforest, only 2-3% of the flowers on the cocoa trees are pollinated.
Importance of Animal Pollination
Habitat Loss, Insecticides and Parasites and Diseases negatively affect both the native bees and the honeybees.
How to Save the Bees?
Bee Life Cycle
Why garden for Pollinators?