Just wanna mention that pollens resist thousands of years and are used in aging sediment layers of soil in paleontology.

Therefore, you may require specific enzymes (like bees) or very low pH to digest them.

Thank you, for your answer, Ebrahim.

That's true, pollen resist thousands of years if not eaten, because its extracellular walls are hardly chemically-degradable (but also - in some cases pollen grains does not resist as a whole but are empty and only walls resist). At the same time you can buy and eat pollen pellets considered to be a beneficial diet supplement. A lot of animals consume pollen while not having special adaptation for its digestion. That's what confuses me. Below I paste two links to the papers concerning pollen consumption by predatory invertebrates. In the third one the authors discuss pollen digestion by beetles (in this case the mechanism may be more complicated). I found some literature reporting pollen feeding in various springtails, beetles, ants, mites, harvestman, snails and slugs, bugs, earwings etc (even spiders) that are not considered as pollen-eaters. It seems that facultative feeding on pollen is common in invertebrates. This idea is also supported by the two papers posted above. I would like to read more detailed literature dealing with this issue.

Kind regards!

Article Pollen Feeding and Fitness in Praying Mantids: The Vegetaria...

Article Pollen digestion by flower-feeding Scarabaeidae: protea beet...

Book Relationships of Natural Enemies and Non-Prey Foods

Please check the following link for said query.

http://link.springer.com/article/10.1007/BF02436031#page-1

Thank you for your answer, Arvind.

 Michal:

Have a look at this old paper for insights:

http://www4.ncsu.edu/~jhhunt/PollenProteases.pdf

Best

Syed

Thank you.

Whether digestion is difficult or not will depend on the digestive systems of the animal species involved. And, difficult versus slow should be distinguished. In honeybees the workers digest the pollen and produce a protein-rich secretion with which they feed the queen and larvae, to increase egg laying and development rates. I wrote a short paper for Bee World 73:77-89, 1991 on the implications of pollen digestion and the evolution of sociality in bees.

Thank you for your answer.

Dear Michal,

You never mentioned which animal species you want to feed pollen. Basically, plant food materials are not easily digestible to monogastric animals such as poultry and humans except rabbits which have specialized caecum with microorganisms (similar to ruminants) in addition to copraphogia/caecotrophy. However, ruminant animals easily digest plant materials including pollen because they have specialized rumen for this purpose. If pollen is to be easily digested by no-ruminants, appropriate processing techniques should be developed.  Elly  

Thank you.

Dear all,

I would like to mention toxicity of pollen which plays a major role for oligolectic bees; see for example: Praz C.J., Müller A., Dorn S. (2008) Specialized bees fail to develop on non-host pollen: Do plants chemically protect their pollen? Ecology 89, 795–

804.

Klaus

Thank you very much, this issue definitely should be taken into consideration.

There is quite a variance in the digestibility of pollen as this depends on several factors. As H. H. W. Velthuis said it depends on the digestive systems of the animal species involved but also keep in mind that every plant species produces pollen with different characteristics and chemical properties. On average a pollen sample will contain:

water 16%

protein 20%

free aminoacids 22%

sugars 37%

other substances (minerals, vitamins, etc.) 5%

Obviously, if pollen is consumed fresh, the high content of water will/should accelerate digestion however, pollen that is sold on the market has to be dehydrated because the same water during storage would spoil this product. Molded pollen, or fermented pollen could be noxious to human health. See also:

Contessi Alberto (2009). Le api. Biologia, allevamento, prodotti. 3rd Ed. Edagricole, Italy.

hardly digestible