Viral species differentially influence macronutrient preferences based on honey bee genotype

Area of Science:

• Apiculture and Insect Pathology
• Animal Nutrition and Immunology

Background:

• Honey bee (Apis mellifera) health and colony survival are influenced by diet quantity and macronutrient composition, affecting immune responses.
• Chronic bee paralysis virus (CBPV) and deformed wing virus (DWV) are significant threats to honey bee populations globally.

Purpose of the Study:

• To investigate how food quantity and macronutrient preferences mediate immune responses in honey bees challenged with CBPV and DWV.
• To compare dietary consumption and macronutrient preferences among Varroa-resistant (Pol-Line, Russian) and Varroa-susceptible (Italian) honey bee stocks.

Main Methods:

• Honey bee stocks (Italian, Pol-Line, Russian) were fed pollen-substitute diets and syrup.
• Consumption rates and macronutrient (protein:lipid ratio) preferences were measured.
• Bees were injected with CBPV or DWV to assess treatment effects on diet consumption and preferences.

Main Results:

• Italian bees consumed more diet than Pol-Line and Russian bees, but Italian and Russian bees selected higher protein:lipid (P:L) ratios.
• CBPV injection positively correlated with syrup consumption, while DWV did not show a significant correlation.
• The interaction between bee stock and virus treatment significantly affected P:L ratios of consumed diets, with differing trends for CBPV and DWV.

Conclusions:

• Macronutrient preferences vary with honey bee virus species, potentially reflecting different energetic demands of immune responses.
• Interactions between virus species and honey bee genotypes suggest diverse mechanisms of viral resistance or tolerance.