So doing a little more research into the domino effect of what would happen if the bumblebee was to go extinct, I did not find any massively detailed about what would happen but what I did find was quite shocking. Some describing it as the beginning of the 6th mass extinction which would end the world as we know it. Although it was again blurry around how the down fall happens but what I have managed to gather from the reports I have read is as follows:
The Bee is said to pollinate 70% of all the plants/crops on the planet. This would be the first victim of the lack of the bee. This lack of pollination would also effect trees. Many of the plants would die out which would also kill off a lot of are food source. However this would also affect herbivores, for example, sheep cows etc which would die out due to the lack of food. This in turn would effect predators as the herbivores would be dyeing out and thus no food the predator. Finally the human race would begin to die out due to a lack of food and most probably war. This would become the 6th mass extinction.
In the image below I have just drawn out a basic symbol for these key points to the worlds end.