How fast do blossoms manufacture nectar?

The only thing i could find was on the Dutch Wikipedia.
What follows is my translation.
It says that flowers produce nectar with their honey glands.
This to make the bees and the birds and the bats and the butterflies to fertilize(?) them (when they come to eat the nectar, they have to pass the reproductive organs (since the nectar is to be found in the bottom of the flower), which they will touch, thus transporting the pollen to other flowers).
Flowers that want to attract bees make less nectar then flowers who do the same for birds and bats.
Bees that are choosing those flowers will have to make more air miles and be visiting hundreds of flowers a day (which is highly effective for that type of flower).
Flowers that use animals for their reproduction produce nectar several times per day.
Edit: Obviously it’s something that is already known to you, how the birds and the bees and the honey works…, so maybe i could have skipped that whole part.

I found some links to actual studies. Here is another that is cited in others. And here is yet another with several promising links as well as an interesting study about jasmonic acid which is apparently aregulator of some sort.
GQ

I now have a new nickname for a certain part of the anatomy; honey gland. Thanks rebbel.

GQ by the way * sigh * it made me feel all National Geographicy this morning. Way to start the day. What Trillian linked cannot be improved upon.