John Lewis wrote
 
> After about ten months of observations I have concluded that mango
> trees do not produce enough nectar for the bees to convert to excess honey
> and that the bees do not collect pollen from these trees.
 
I agree with your observation.  I had bees working mangoes in north Queensland when I lived there and, although they worked the mango flowers hard, there was no surplus nectar in the boxes.
 
I know beekeepers who professionally pollinate mangoes and they say the same thing.  Those that claim to have got a honey crop off mangoes have not, in my opinion, looked over the boundary fence at what was flowering outside.  I have tasted so called mango honey and it tasted more like honey from the trees that were flowering outside the orchard.
 
> If anyone has experience with the pollination of passion fruit I would like
> to speak with you.
 
I have seen bees on passionfruit.  With the large flower, I have seen bees walking in and out of the flower without touching the anthers.  However, those that put bees on passionfruit say the growers have noticed an increase in yield when bees are there compared to when they are not.  So as long as the grower is happy, so should the beekeeper, particularly if the beekeeper is being paid for the service.
 
Again, I believe that there is no honey yield from the passionfruit and you would need to keep an eye on the hives if there are no other sources of nectar or pollen nearby.
 
Trevor Weatherhead
AUSTRALIA