I don't really know much (or anything) about that. But I haven't noticed any change of behaviour on bees coming onto my garden. The only change is when I remove one of the plants they like to lick they stop coming... So am currently working on having a bee free garden for next summer by having all those plants/flowers identified and removed.
Now go suck my "magnets" you bees (and wasps)!
I can understand not wanting wasps but whats wrong with Bees?
I noticed Bees missing about 3 years ago and a small green metallic fly was pollinating my berry bushes so i guess life is not quite as fragile as we think. Last year i had some "Queens Bees" start showing up.
Well, wasps can bite and bees can sting, can't they? Enough reason to not welcome them to my garden I think. To be honest I have never been sting by a bee but.... I hate when one disturbs my peace of mind while I am sunbathing because I think/fear it could sting me. I don't even like flies nor mosquitoes even if those won't bite me.