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No Genetic Tradeoffs between Hygienic Behavior and Individual Innate Immunity in the Honey Bee, Apis mellifera
Many animals have individual and social mechanisms for combating pathogens. Animals may exhibit short-term physiological tradeoffs between social and individual immunity because the latter is often energetically costly. Genetic tradeoffs between these two traits can also occur if mutations that enhance social immunity diminish individual immunity, or vice versa. Physiological tradeoffs between individual and social immunity have been previously documented in insects, but there has been no study of genetic tradeoffs involving these traits. There is strong evidence that some genes influence both innate immunity and behavior in social insects – a prerequisite for genetic tradeoffs. Quantifying genetic tradeoffs is critical for understanding the evolution of immunity in social insects and for devising effective strategies for breeding disease-resistant pollinator populations. We conducted two experiments to test the hypothesis of a genetic tradeoff between social and individual immunity in the honey bee, Apis mellifera. First, we estimated the relative contribution of genetics to individual variation in innate immunity of honey bee workers, as only heritable traits can experience genetic tradeoffs. Second, we examined if worker bees with hygienic sisters have reduced individual innate immune response. We genotyped several hundred workers from two colonies and found that patriline genotype does not significantly influence the antimicrobial activity of a worker’s hemolymph. Further, we did not find a negative correlation between hygienic behavior and the average antimicrobial activity of a worker’s hemolymph across 30 honey bee colonies. Taken together, our work indicates no genetic tradeoffs between hygienic behavior and innate immunity in honey bees. Our work suggests that using artificial selection to increase hygienic behavior of honey bee colonies is not expected to concurrently compromise individual innate immunity of worker bees.
http://www.plosone.org/article/info:doi/10.1371/journal.pone.0104214
 

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The study used (10) year-old double deeps and (20) 4-frame nucs. The supplementary material presents the raw data for mite count (using sugar shake) and hygenic impulse (using freeze killed brood).

I downloaded the supplementary raw data and looked for correlation between mite # and hygenic % in the two colony classes.
1. No correlation between Hyg% and Mite#
2. 4 frame Young Nucs were carrying mites at near the economic threshold.
3. Limited number of hives had "broken out" and were carrying mites at >20 per 250 ml (about 1 cup)

My conclusions:
I think the Hygenic measure is a poor predictor of mite management capacity, and this study reinforces that observation.
Young Nucs can carry epidemic level of mites, the "first year free" idea is not really supported.
Mite explosion is idiosyncratic to the measured variables (including their innate immune assay (the ZOI variable).

 
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