Measuring biological age to assess colony demographics in honeybees

PLoS One. 2018 Dec 13;13(12):e0209192. doi: 10.1371/journal.pone.0209192. eCollection 2018.

Abstract

Honeybee colonies are increasingly exposed to environmental stress factors, which can lead to their decline or failure. However, there are major gaps in stressor risk assessment due to the difficulty of assessing the honeybee colony state and detecting abnormal events. Since stress factors usually induce a demographic disturbance in the colony (e.g. loss of foragers, early transition from nurse to forager state), we suggest that disturbances could be revealed indirectly by measuring the age- and task-related physiological state of bees, which can be referred to as biological age (an indicator of the changes in physiological state that occur throughout an individual lifespan). We therefore estimated the biological age of bees from the relationship between age and biomarkers of task specialization (vitellogenin and the adipokinetic hormone receptor). This relationship was determined from a calibrated sample set of known-age bees and mathematically modelled for biological age prediction. Then, we determined throughout the foraging season the evolution of the biological age of bees from colonies with low (conventional apiary) or high Varroa destructor infestation rates (organic apiary). We found that the biological age of bees from the conventional apiary progressively decreased from the spring (17 days) to the fall (6 days). However, in colonies from the organic apiary, the population aged from spring (13 days) to summer (18.5 days) and then rejuvenated in the fall (13 days) after Varroa treatment. Biological age was positively correlated with the amount of brood (open and closed cells) in the apiary with low Varroa pressure, and negatively correlated with Varroa infestation level in the apiary with high Varroa pressure. Altogether, these results show that the estimation of biological age is a useful and effective method for assessing colony demographic state and likely detrimental effects of stress factors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aging
  • Algorithms
  • Animals
  • Beekeeping
  • Bees / parasitology*
  • Bees / physiology*
  • Gene Expression
  • Insect Proteins / metabolism
  • Mites*
  • Models, Biological
  • Seasons
  • Stress, Physiological
  • Varroidae
  • Vitellogenins / metabolism

Substances

  • Insect Proteins
  • Vitellogenins

Grants and funding

This work was funded by a grant from France Agrimer (Probee, 14-01-R), http://www.franceagrimer.fr/. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.