There are two main types of pruning: one that gives a shape to the plant (fence, topiaria, training in the youth of the trees...) and another that makes the grain of the fruit more and faster.
The plants bear fruit and seed for new trees to be born that give continuity to their caste. If the plant lives very well, it will not spend much energy to bear the fruit, it is she who holds many raw, thick and steep castes. Pruning wants to fly this: do a lot of wounds to the plant, prevent the passage to where it wants to grow, tie it, tilt it, etc. The plant sits in the mint and in case it starts to bear fruit. This is the pruning to bear more fruit.
This pruned tree has to bring the flower to fructify. And when she opens the flowers, she needs pollinators. Some fruit trees have enough wind to make this exchange of pollen from flower to flower: hazelnuts and nogales, for example. Many others need pollen carriers, but birds (hummingbird, bats, etc.) It's insects. Beetles, flies, butterflies, moths, ants, bees and wasp bees, etc., do the indispensable work in fruticulture. The treatment between insects and plants is the success of the evolution of flowering plants. At the Jurassic, 130 million years ago, when flowering plants were created, he committed to collaborating with insects. The key is in flower design: nectar and pollen, in exchange for a little food, insects will conduct pollination. Today, they account for about 90 percent of the world's plants. These plants and pollinators have evolved together, adapting the plants flowers (shape, smell, length…) and insects the body parts (mouth, spirit).
Sometimes the mutual need is great. A group of researchers from the Swiss public university ETH of Zurich (Pashalidou, Lambert, Peybernes, Mescher and De Moraes) analyzed the behavior of a singular bumblebee and came to a surprising conclusion, as well as to publish it in the well-known journal Science: while the bumblebee builds the summer colony, the pollen needs. However, not every year the same days of flowering occur, which can lead to hunger. Faced with the shortage of pollen, bees actively damaged the leaves of the plants in a special way, resulting in a flowering 30 days earlier. Similar damage by researchers did not anticipate flourishing. The bottom line is that apiculture has a special method to accelerate flowering. Curl the plant.
What fruit holders do with pruning is done by bumblebees, know for millions of years.