[mvidal01]

Some insects gather nectar from a flower and don't pollinate the flower. This is called nectar robbing.

See https://www.backyardecology.net/not-all-flower-visitors-are-...

[baxtr]

What’s the best security control against this robbery?!

[rags2riches]

This is what the shape of the flower and its placement of the stamen and pistils are all about.

[cyberjar]

If it becomes a problem I would imagine that most victim plants will evolve certain defence mechanisms. For example, some insects will simply chew through flowers to reach the nectar stores - so I think in such cases a flower would just evolve a tougher skin, or secrete something that deters insects from doing that.

[adm4]

great idea... How do you make sure there is an exchange.