I do know that during our four year drought in my part of California ... it's still continuing in southern California ... I saw very few pollinators. This year, we had a wet winter and the bees are back ...
This morning as I was spraying down plants to slow down the transpiration rate due to our triple digit temps, I found myself feeling sorry for the butterflies visiting the garden because I only had fried blooms to offer them. They did visit the plants for a sip of water and moved on. During the drought, I hardly saw any butterflies, either.