In some fields pollinators will only work blossoms in the morning, until around 9 or 10 AM. In other fields of the same plant species, pollinators are collecting nectar from dawn to dusk.
In some orchards, honeybees prefer the dandelions and healing herbs (weeds) to the fruit tree blossoms. In other orchards, bees ignore the dandelions, and are visiting fruit tree blossoms all day long.
Healthy plants produce larger amounts of nectar that has a higher sugar content, which increases it’s attractiveness to pollinators.
Less healthy plants have less nectar, and the sugar content can be dramatically lower.
As an example, the sugar content of apple nectar can vary from a low of 2% up to 60%.
When apple blossom nectar contains 2% sugar, do you think honeybees will prefer the dandelions over the apples or vice versa? What about when the sugar concentration is 60% in the nectar?
An agronomist with decades of experience has reported that honeybees avoid visiting flowers where the nectar brix is below 7, since they consume more energy than they gain in return.
Before our transition to regenerative agriculture and nutrition management, honeybees would only visit cucurbit crop blossoms until 9 AM. Within two years of changing nutrition management, they were present all day.
You can observe how much time a bee spends on each flower. A flower worth visiting for 80 or 90 seconds will contain much more nectar (and of higher quality) than a flower only worth visiting for 5 seconds.
You can also observe how long during the day pollinators are active in a crop.
Both of these observations will correlate to nectar attractiveness, and to overall plant brix readings and health.