See this recent paper. I doubt they can discriminate infected pollen.

Furst, M. A., et al. (2014). "Disease associations between honeybees and bumblebees as a threat to wild pollinators." Nature 506(7488): 364-366.

Emerging infectious diseases (EIDs) pose a risk to human welfare, both directly1 and indirectly, by affecting managed livestock and wildlife that provide valuable resources and ecosystem services, such as the pollination of crops. Honeybees (Apis mellifera), the prevailing managed insect crop pollinator, suffer from a range of emerging and exotic high-impact pathogens, and population maintenance requires active management by beekeepers to control them. Wild pollinators such as bumblebees (Bombus spp.) are in global decline, one cause of which may be pathogen spillover from managed pollinators like honeybees or commercial colonies of bumblebees. Here we use a combination of infection experiments and landscape-scale field data to show that honeybee EIDs are indeed widespread infectious agents within the pollinator assemblage. The prevalence of deformed wing virus (DWV) and the exotic parasite Nosema ceranae in honeybees and bumblebees is linked; as honeybees have higher DWV prevalence, and sympatric bumblebees and honeybees are infected by the same DWV strains, Apis is the likely source of at least one major EID in wild pollinators. Lessons learned from vertebrates highlight the need for increased pathogen control in managed bee species to maintain wild pollinators, as declines in native pollinators may be caused by interspecies pathogen transmission originating from managed pollinators.

Dear David,

Happy to see you in researchgate!

Many thanks for your complete answers. I could not see the link because bbc is filtered here. So the answer is yes. They can transfer the infected pollen. The main question is if pollens could infected by Viruses or not. I heard that viruses can not transfer by pollen, is it right?

Cheers

I don't know the answer about virus transmission. I think the transmission could be via other mechanisms, such as contamination of floral nectar by the tongue of a bee, or feces on the flower, etc.

There is a recent paper: Li, Ji Lian, R. Scott Cornman, Jay D. Evans, Jeffery S. Pettis, Yan Zhao, Charles Murphy, Wen Jun Peng et al. "Systemic Spread and Propagation of a Plant-Pathogenic Virus in European Honeybees, Apis mellifera." mBio 5, no. 1 (2014): e00898-13, showing that bees can actually host a plant virus. That is a nice study.

We tried a bit longer, to see if bees could transmit a viroid from sick plants to healthy plants within and between species, however without success: http://dx.doi.org/10.1007/s10658-012-9937-0

Pollination is complex, and things happen, we haven't known of before.

Here's a recent paper that reviews what we know on the subject:

McArt, S. H., Koch, H., Irwin, R. E., Adler, L. S. (2014), Arranging the bouquet of disease: floral traits and the transmission of plant and animal pathogens. Ecology Letters. doi: 10.1111/ele.12257

The answer is "yes".

There are a number of plant pathogens that pollinating/foraging insects, including bees, transfer from plant to plant. A few, such as Ustilago violacea and Monilinia vaccinii-corymbosi have pollinators/anthophiles as part of their life-histories. There are other examples. The yeast, Metschnikowia reukaufii is also dispersed effectively between flowers and plants by anthophiles. I think there is published information on raspberry dwarfing virus vectored by pollen by pollen dusted bees. If one considers that mites can be agents of disease, then there are examples of those dispersed by bird pollinators (humminbirds).

Then there is the evidence that pollinator diseases can be transmitted from pollinator to pollinator via floral intermediaries. This is implicated in various honeybee diseases, and even for the spread of Varroa mites.

Recently developed technology has used managed pollinators to disperse microbial biological control agents to flowering crops to effect suppression of fungal and insect pests.

I have written several papers over the years on all those aspects of diseases spread to crop plants and amongst flower visitors. Most of my papers have been uploaded to RG, so please feel free to consult them, and ask more questions.

What is the system you are interested in.

Best wishes,

Peter

Peter Kevan

Hello, 

What are the main hypothesis of viruses or other pollinator pathogens like Crithidia spp and Nosema spp may arrive on flowers pollen or nectar ? Is it by infected faeces deposition, infected salivary (when feeding on flowers),  infected cuticle and contact with floral surfaces ? 

Thanks you,

Best wishes,

Gregoire