I had not heard this before. It appears that plant compounds that honey bees consume may have an inhibitory effect on their reproductive abilities.
p-coumaric acid is a component in pollen and honey that may inhibit honey bee reproductive development.
Queen honey bees are never actually fed pollen and honey directly, ingesting ONLY royal jelly. Royal jelly was previously credited with containing the components needed to turn a larva into a queen, but it appears that isn't quite the whole story, or even the real story.
This also makes me kind of wonder if honey has any effects on ANTS? Presumably not, because people use it all the time without colony failure and it sounds like not even bumble bees make royal jelly.
But still.... ?!??!