Re: Summer bees vs winter bees?
I've posted this before, but it really summarizes what I think causes most problems with our bees. Do insecticides play a part, I believe so. But also fungicides, miticides, etc. But virus issues, vectored by varroa are the real culprit. IMO, keep varroa under control and the other issues are manageable.
PLoS One. 2012;7(8):e43562. doi: 10.1371/journal.pone.0043562. Epub 2012 Aug 21.
Pathogen webs in collapsing honey bee colonies.
Cornman RS, Tarpy DR, Chen Y, Jeffreys L, Lopez D, Pettis JS, vanEngelsdorp D, Evans JD.
Source
Bee Research Laboratory, Agricultural Research Service, United States Department of Agriculture, Beltsville, Maryland, United States of America.
Abstract
Recent losses in honey bee colonies are unusual in their severity, geographical distribution, and, in some cases, failure to present recognized characteristics of known disease. Domesticated honey bees face numerous pests and pathogens, tempting hypotheses that colony collapses arise from exposure to new or resurgent pathogens. Here we explore the incidence and abundance of currently known honey bee pathogens in colonies suffering from Colony Collapse Disorder (CCD), otherwise weak colonies, and strong colonies from across the United States. Although pathogen identities differed between the eastern and western United States, there was a greater incidence and abundance of pathogens in CCD colonies. Pathogen loads were highly covariant in CCD but not control hives, suggesting that CCD colonies rapidly become susceptible to a diverse set of pathogens, or that co-infections can act synergistically to produce the rapid depletion of workers that characterizes the disorder. We also tested workers from a CCD-free apiary to confirm that significant positive correlations among pathogen loads can develop at the level of individual bees and not merely as a secondary effect of CCD. This observation and other recent data highlight pathogen interactions as important components of bee disease. Finally, we used deep RNA sequencing to further characterize microbial diversity in CCD and non-CCD hives. We identified novel strains of the recently described Lake Sinai viruses (LSV) and found evidence of a shift in gut bacterial composition that may be a biomarker of CCD. The results are discussed with respect to host-parasite interactions and other environmental stressors of honey bees.
PMID:
22927991
[PubMed - indexed for MEDLINE]
PMCID:
PMC3424165
http://www.ncbi.nlm.nih.gov/pubmed/22927991
full paper free at the above link.