Comparative assessment of food consumption, longevity, thermoregulation, and molecular health markers in mite-resistant and Italian honey bee stocks

Authors: Meikle, William; Weiss, Milagra; Adjaye, Daniela; Ricigliano, Vincent

Submitted to: Apidologie
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/5/2024
Publication Date: 4/25/2024
Citation: Meikle, W.G., Weiss, M., Adjaye, D.F., Ricigliano, V.A. 2024. Comparative assessment of food consumption, longevity, thermoregulation, and molecular health markers in mite-resistant and Italian honey bee stocks. Apidologie. 55. Article 28. https://doi.org/10.1007/s13592-024-01071-x.
DOI: https://doi.org/10.1007/s13592-024-01071-x

Interpretive Summary: It is important, especially with climate change, to determine the characteristics of different bee races so that we can select for those characteristics that might help bee colonies in the field. We conducted three cage studies using newly-emerged adult bees, in an incubator that was warm (30C) for 12 hours and cool (15C) for 12 hours every day, with bees from three different bee races: Pol-line, Russian and Italian. The objective was to monitor how much food the bees from the different races ate, how warm they kept their cluster in the cage when the temperature dropped, and how long they lived. We also measured gene expression, including one gene involving nutritional state (vitellogenin), two genes involving stress (heat shock proteins) and one gene involving disease (Deformed Wing Virus B, or DWV-B). We found that the Italian bees ate more per day but had lower cluster temperatures and shorter adult lives than the other two races. We also found that they had less vitellogenin (lower nutritional state) and more virus than the other two races. Using a mathematical model, we estimated that the Italian bees would need about 16% more brood just to maintain a colony the same size as the Pol-line and Russian bees, which are both considered resistant to bee mites (which transmit DWV-B). This indicates that Pol-line and Russian bees may have important genetic benefits to beekeeping in the U.S.

Technical Abstract: Identifying traits for adaptation to different management and environmental factors is key to maintaining robust honey bee populations under global change. Here, we compared mite resistant (Pol-line and Russian) and Italian honey bee stocks in cage experiments using a variable temperature incubator. We measured feed consumption, thermoregulation, gene expression, and survival replicated thrice across two years. Bee stock had a significant impact on both sugar and pollen consumption (Italian > Russian > Pol-line). Mite resistant stocks had superior thermoregulation and survival relative to Italian stock. This was consistent with increased expression of vitellogenin – a gene which influences worker lifespan – and reduced levels of deformed wing virus (DWV-B) in Pol-line and Russian bees. Modeling results indicated that, to maintain the same colony size, colonies of the Italian stock would need about 16% more sealed brood to offset the reduced lifespans of worker populations. Our findings provide novel fine-scale insights regarding the effects of genetic variation on bee attributes that may influence colony-level productivity and health.