pollinators

Looking at the pictures it’s hard to believe that this has been happening for 100 million years! Plants and pollinators are entwined in a dance of co-dependency and it is such a fragile relationship that should one party be removed, life as we know it would be very different. So why did it all start? Why did a plant start making flowers and using complicated chemical reactions to make attractive scents and make nectar, all of which are very expensive in terms of energy?