Viral species differentially influence macronutrient preferences based on honey bee genotype

Authors: Penn, Hannah; Simone-Finstrom, Michael; De Guzman, Lilia; Tokarz, Philip; Dickens, Rachel

Submitted to: Biology Open
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/5/2022
Publication Date: 9/29/2022
Citation: Penn, H., Simone-Finstrom, M., De Guzman, L.I., Tokarz, P.G., Dickens, R.D. 2022. Viral species differentially influence macronutrient preferences based on honey bee genotype. Biology Open. 11(10):bio059039. https://doi.org/10.1242/bio.059039.
DOI: https://doi.org/10.1242/bio.059039

Interpretive Summary: Honey bee individuals experiencing virus-induced illnesses may change both the quantity and the nutritional profiles of the foods (pollen and nectar) that they consume in an attempt to self-medicate. This study sought to determine if this was the case for two common honey bee viruses - Deformed wing virus genotype A (DWV-A) and Chronic bee paralysis virus (CBPV). DWV-A often does not kill bees outright but may cause symptoms such as crumpled wings, while CBPV is more likely to cause neurological damage and death. We examined how bees change their food consumption patterns due to viral infection for three different stocks of honey bees, two of which (Pol-Line and Russian) have been bred for resistance to the virus-transmitting varroa mite. We found that bees changed their eating habits based on the level of infection and the specific type of viral infection present. DWV-A generally had fewer impacts than CBPV on bee food preferences. CBPV caused bees to increase their protein and nectar consumption but decrease overall pollen consumption. The different stocks of bees consumed different quantities of food, with mite-susceptible Italian bees eating the most pollen and nectar. The stocks with known mite-resistance also differed from the mite-susceptible bees in their reactions to infections via both food quantity and nutritional preferences.

Technical Abstract: The quantity and macronutrients of food resources contribute to the health of individual honey bees and colony survival by mediating immune responses. Here, we determined if this held true for bees injected with Deformed wing virus genotype A (DWV-A) and Chronic bee paralysis virus (CBPV), two common honey bee ssRNA viruses known to impact individual bee health. Pollen-substitute diet and syrup consumption rates and macronutrient preferences of two Varroa mite-resistant stocks (Pol-Line and Russian bees) were compared to that of Italian bees known to be susceptible to mites. Honey bee genotypes varied in overall diet consumption, where Italian bees consumed more than Pol-Line and Russian bees. However, the protein: lipid (P:L) ratios of diet consumed by the Italian and Russian bees were greater than that of the Pol-Line. Regardless of stock, virus type and titers had different effects on diet consumption as well as changes in P:L. CBPV was positively associated with P:L ratios and syrup consumption, but these effects varied when coupled with stock and injection treatment. In contrast, DWV-A was not correlated with consumed diet. Variation in macronutrient preferences based on viral type and titer may indicate differences in energetic costs associated with immune responses to viral infections impacting different systems. Further, the type and titer of virus interacted with bee genotype to influence diet preferences and mortality, indicating different mechanisms of viral resistance or tolerance among honey bee genotypes.