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ARS Home » Southeast Area » Baton Rouge, Louisiana » Honey Bee Lab » Research » Publications at this Location » Publication #364410
Research Project: Genetics and Breeding in Support of Honey Bee Health

Location: Honey Bee Breeding, Genetics, and Physiology Research

Title: Susceptibility to viral infection in honey bees driven by genotypic differences in tolerance and resistance

Author
item Simone-Finstrom, Michael
item PENN, HANNAH - LSU Agcenter
item HEALY, KRISTEN - LSU Agcenter

Submitted to: Entomology Society of America Pacific Branch Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 6/1/2019
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The ectoparasitic mite Varroa destructor is the biggest threat affecting honey bee health in large part because of the viruses that mites vector while feeding during reproduction and development on honey bee pupae. Deformed wing virus (DWV), in particular, has been associated with colony losses. Because of the significance of Varroa-DWV dynamics, there has been much interest in the relationship between colony mite infestation and viral prevalence. In a few cases, it has been noted that colonies that have natural resistance mechanisms against Varroa have lower incidences of DWV infection. However in other populations mite-resistance seems to be correlated with tolerance to DWV, meaning that mite-resistant colonies survive with high levels of DWV and exhibit fewer symptoms. To clarify whether resistance (maintain low viral titers despite infection) or tolerance (high survival, no symptoms with high virus) to DWV appears to be driving these differential effects, a series of experiments have been conducted. 1) Pupae from single-drone inseminated queens were injected with low, moderate or high levels of a DWV inoculum and followed through emergence to examine survival and expression of symptoms. A subset of these pupae were analyzed from putatively resistant and susceptible colonies to determine differences in viral titer and antiviral responses as a way to detect whether the colonies exhibit resistance or tolerance to DWV. Additionally, pupae from the same colonies that displayed differential symptom development after injection with the same dose were examined to understand possible individual differences in tolerance or resistance to viral infection. 2) Newly emerged bees collected from 3 mite-resistant stocks (Russian, Pol-line and Saskatraz) and 2 mite-susceptible stocks (Italian and Carniolan) were injected with a DWV inoculum. Bees were subsampled over time to determine how bee genotype influences rate of dissemination of the virus throughout an individual by analyzing viral load in different. Results suggest that tolerance may be the major factor explaining genotypic differences in susceptibility and development of symptoms in pupae. Further, sufficient variation exists within a stock and across stocks with some stocks exhibiting greater variation than others indicating that tests for viral susceptibility could be valuable for breeding programs.