Kindly see here too..

https://oup.silverchair-cdn.com/oup/backfile/Content_public/Journal/aob/103/9/10.1093/aob/mcp122/2/mcp122.pdf?Expires=1491579397&Signature=Ngkd77xGXP~CZNteQJW7o5WYHFatXV0hM0j1SiJnOvpvDHDZQ3GLEhwMBVjK1NV5YLhrNBUou1HIizeOB~8t4eu~j6NIUwg3ygwvAkXG~xJsF0252dUStpi0p3JEj7EWFL-wS~vxXHztxg-y4gJlSXI5D0ktulSOid67FSl1F~JZ2h038ROQxeqMBAzvwSnOvQdtEUzVMjimtS~M2W6Yb05vQNv1kcR-BWgdVHwWPLzBYm0BpDBmVucyTqmsw6YzT6-d86AWkj1Ym5ytklWj33HMAOTz-91wQk7sp6ceDQclSbZLB1r3ulK~7cWEi72FmwEcQSJZqj0IgSFVvSnCDA__&Key-Pair-Id=APKAIUCZBIA4LVPAVW3Q

Dear Dr. Singh,

thank you very much for this paper.

Kind regards,

Michał Filipiak

Dear Michal,

                        I had the experience of working on pollen collection by Apis mellifera. The colonies were placed in area cultivated with mustard crop. Bees were bringing only mustard pollen for the first 15 days, thereafter when the mustard came in full bloom, bees to my surprise also tried to bring pollen from Asphodelus weed  in a quantity quiet  equal to mustard pollen though the population of asphodelus weed was less compared to full fledged mustard area. certainly nutritional demands may have prompted bees to collect pollen from other sources

Thank you very much for sharing your observation!

According to the literature data bees (Apidae, not only honeybee) favor certain species of pollen. These preferences might be related to the nutritional quality of the pollen but do not appear to be related to the total protein content of the pollen. It was also demonstrated that honeybees significantly prefer multifloral pollen to single-species pollen. You will find adequate citations on the 9th page of the paper mentioned in my question. 

Kind regards,

Michał Filipiak

This study may contribute to the discussion:

Article Generalist social bees maximize diversity intake in plant sp...

The amount of nutrients in plants it depends on their content in the soil and and the particularities of certain species (Urtica dioica, for example is a plant which grown on soils rich in N). Therefore these mason bees may change their food spectrum, feeding on pollen from other plants, plants through with different mechanisms that can supplement their low amount of nutrients in the soil (carnivorous plants, for example - Drosera rotundifolia,Pinguicula vulgaris, Utricularia vulgaris, etc)

In most cases, the  nature species have a great ability to adapt.

Dear Professor Gheorghe,

thank you for your answer!

I think that intraspecific variability of pollen nutritional value, related to environmental conditions, is possible within the physiological frame, related to the main function of pollen - fertilization.

However, it is also possible that contents of atoms of certain elements in pollen of specific plant species are conservative and related to the reproductive function of pollen.

Do you know any studies testing these two mutually exclusive hypotheses?

Kind regards,

Michał Filipiak

Indeed the variability of pollen nutritional value is related to environmental conditions only for euribionte - organism biologically versatile, adaptable to different environmental and nutritional conditions such as to permit the colonization of different habitats (contrary: stenobionte) - species. In particular conditions these forming so-called eco forms.

I am sorry, unfortunately I do not know a study to verify the hypothesis

Iuliana

Thank you very much!

Michał Filipiak

Thank you for the two interesting papers. You ask: Is it possible that the nutritional quality of pollen influences foraging behavior and life-history traits of pollen-eaters? My answer is that if these qualities vary among species - as we know they do - then natural selection would produce foragers that are influenced by them. Where pollen is collected but not eaten, such as by male or sterile worker bees, then their ability to assess pollen quality may be limited, but all solitary bee females seem to eat pollen for the protein needed to develop eggs, so post-ingestive feedback should give them detailed information on quality. I know of no data on this, but some solitary bees are narrow specialists for pollen so it would be interesting to start by looking at the quality of the pollen taxa they depend on. Remember also that nectar is not just sugar and water. so you need to look at the whole diet.

Dear Professor Corlett,

thank you for your answer!

Michał Filipiak

Here is a study related to this question:

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0183236

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0183236

Article Ecological stoichiometry of the honeybee: Pollen diversity a...