Transcriptional Response of Honey Bee (\u3cem\u3eApis mellifera\u3c/em\u3e) to Differential Nutritional Status and \u3cem\u3eNosema\u3c/em\u3e Infection

Background: Bees are confronting several environmental challenges, including the intermingled effects of malnutrition and disease. Intuitively, pollen is the healthiest nutritional choice, however, commercial substitutes, such as Bee-Pro and MegaBee, are widely used. Herein we examined how feeding natural and artificial diets shapes transcription in the abdomen of the honey bee, and how transcription shifts in combination with Nosema parasitism. Results: Gene ontology enrichment revealed that, compared with poor diet (carbohydrates [C]), bees fed pollen (P \u3e C), Bee-Pro (B \u3e C), and MegaBee (M \u3e C) showed a broad upregulation of metabolic processes, especially lipids; however, pollen feeding promoted more functions, and superior proteolysis. The superiority of the pollen diet was also evident through the remarkable overexpression of vitellogenin in bees fed pollen instead of MegaBee or Bee-Pro. Upregulation of bioprocesses under carbohydrates feeding compared to pollen (C \u3e P) provided a clear poor nutritional status, uncovering stark expression changes that were slight or absent relatively to Bee-Pro (C \u3e B) or MegaBee (C \u3e M). Poor diet feeding (C \u3e P) induced starvation response genes and hippo signaling pathway, while it repressed growth through different mechanisms. Carbohydrate feeding (C \u3e P) also elicited ‘adult behavior’, and developmental processes suggesting transition to foraging. Finally, it altered the ‘circadian rhythm’, reflecting the role of this mechanism in the adaptation to nutritional stress in mammals. Nosema-infected bees fed pollen compared to carbohydrates (PN \u3e CN) upheld certain bioprocesses of uninfected bees (P \u3e C). Poor nutritional status was more apparent against pollen (CN \u3e PN) than Bee-Pro (CN \u3e BN) or MegaBee (CN \u3e MN). Nosema accentuated the effects of malnutrition since more starvation-response genes and stress response mechanisms were upregulated in CN \u3e PN compared to C \u3e P. The bioprocess ‘Macromolecular complex assembly’ was also enriched in CN \u3e PN, and involved genes associated with human HIV and/or influenza, thus providing potential candidates for bee-Nosema interactions. Finally, the enzyme Duox emerged as essential for guts defense in bees, similarly to Drosophila. Conclusions: These results provide evidence of the superior nutritional status of bees fed pollen instead of artificial substitutes in terms of overall health, even in the presence of a pathogen

Temporal Analysis of the Honey Bee Microbiome Reveals Four Novel Viruses and Seasonal Prevalence of Known Viruses, Nosema, and Crithidia

Honey bees (Apis mellifera) play a critical role in global food production as pollinators of numerous crops. Recently, honey bee populations in the United States, Canada, and Europe have suffered an unexplained increase in annual losses due to a phenomenon known as Colony Collapse Disorder (CCD). Epidemiological analysis of CCD is confounded by a relative dearth of bee pathogen field studies. To identify what constitutes an abnormal pathophysiological condition in a honey bee colony, it is critical to have characterized the spectrum of exogenous infectious agents in healthy hives over time. We conducted a prospective study of a large scale migratory bee keeping operation using high-frequency sampling paired with comprehensive molecular detection methods, including a custom microarray, qPCR, and ultra deep sequencing. We established seasonal incidence and abundance of known viruses, Nosema sp., Crithidia mellificae, and bacteria. Ultra deep sequence analysis further identified four novel RNA viruses, two of which were the most abundant observed components of the honey bee microbiome (∼1011 viruses per honey bee). Our results demonstrate episodic viral incidence and distinct pathogen patterns between summer and winter time-points. Peak infection of common honey bee viruses and Nosema occurred in the summer, whereas levels of the trypanosomatid Crithidia mellificae and Lake Sinai virus 2, a novel virus, peaked in January

Colony Collapse Disorder: A Descriptive Study

BACKGROUND: Over the last two winters, there have been large-scale, unexplained losses of managed honey bee (Apis mellifera L.) colonies in the United States. In the absence of a known cause, this syndrome was named Colony Collapse Disorder (CCD) because the main trait was a rapid loss of adult worker bees. We initiated a descriptive epizootiological study in order to better characterize CCD and compare risk factor exposure between populations afflicted by and not afflicted by CCD. METHODS AND PRINCIPAL FINDINGS: Of 61 quantified variables (including adult bee physiology, pathogen loads, and pesticide levels), no single measure emerged as a most-likely cause of CCD. Bees in CCD colonies had higher pathogen loads and were co-infected with a greater number of pathogens than control populations, suggesting either an increased exposure to pathogens or a reduced resistance of bees toward pathogens. Levels of the synthetic acaricide coumaphos (used by beekeepers to control the parasitic mite Varroa destructor) were higher in control colonies than CCD-affected colonies. CONCLUSIONS/SIGNIFICANCE: This is the first comprehensive survey of CCD-affected bee populations that suggests CCD involves an interaction between pathogens and other stress factors. We present evidence that this condition is contagious or the result of exposure to a common risk factor. Potentially important areas for future hypothesis-driven research, including the possible legacy effect of mite parasitism and the role of honey bee resistance to pesticides, are highlighted

Does in-hive pollen transfer by honey bees contribute to cross-pollination and seed set in hybrid cotton?

Whether or not sufficient amounts of cotton pollen are transferred among nestmates in honey bee hives to influence cross-pollination and seed set in cotton was tested. Honey bees foraged on genetic cytoplasmic male sterile (CMS) cotton flowers in greater numbers than on male fertile (MF) flowers, and most of the foragers on MF flowers collected nectar rather than pollen. Pollen-free worker bees either pinned at the hive entrance or released in the hive obtained very little cotton pollen on their bodies from nestmate contacts, although all of them obtained large amounts of pollen from other plant species. Seed set on CMS plants did not decrease significantly with distance from MF plants in 1988 when foraging activity on CMS plants was high relative to that in 1989. In 1989 when there was less foraging activity on CMS flowers, seed set on CMS plants decreased significantly with distance from the MF row. These studies indicate that there were insufficient numbers of honey bees returning to their colonies with significant amounts of cotton pollen on their bodies to ensure effective transfer of cotton pollen among nestmates in the hive