Pollination is a complex process. It’s not as easy as an insect simply visiting a flower.
This is important to remember when talking about which species are the ‘best’ or ‘most important’ pollinators. Simply observing an animal visiting a flower is not, on its own, evidence that the animal is pollinating the flower.
Click on the link for more information: Flower Visitors vs. Pollinators: no evidence that honey bees are the most important pollinator worldwide – Ecology is not a dirty word