Identifying Early Warning Signals of Bee Colony Stress with BEEHAVE

In this study, we utilized the BEEHAVE simulation model to identify early warning indicators of stress in honey bee colonies. This research is crucial for understanding how various stressors impact bee health and for developing effective management strategies to minimize colony losses.

Why Early Warning Signals Matter

Honey bees are essential for pollination and the overall health of our ecosystems. However, they face numerous challenges, including resource stress, Varroa mites, and environmental changes. Detecting stress early in the year is vital for timely interventions that can save colonies from severe impacts later on. Our study aimed to determine which colony-level indicators could reliably signal stress before it leads to significant problems, such as increased winter mortality.

The Six Indicators We Tested

In our simulation experiments using BEEHAVE, we examined six potential indicators of colony stress:

  1. Number of adult bees
  2. Number of capped brood cells (pupae)
  3. Flight activity
  4. Number of Varroa mites
  5. Honey reserves
  6. Brood-bee ratio

These indicators were chosen to cover various aspects of colony health, from population dynamics to resource availability and parasite load.

Key Findings: Brood Cells and Brood-Bee Ratio

Our results indicate that the number of capped brood cells (pupae) and the brood-bee ratio are the most reliable early warning signals of resource stress in the landscape. These indicators provide crucial information about the colony’s reproductive potential and resource balance. Monitoring the number of pupae can be relatively straightforward and offers a clear picture of the colony’s developmental status.

Interestingly, our study found that these indicators are more sensitive to early-year stress compared to other indicators like honey reserves, which are more informative at the end of the season.

Varroa Mites: An Essential Focus

For biotic stress caused by Varroa mites, continuous monitoring remains indispensable. Effective Varroa mite control is critical to prevent the cascading effects of mite infestations over time. Despite the complexity, integrating mite monitoring with other indicators provides a comprehensive view of colony health.

The Power of Simulation Models

The BEEHAVE model has proven invaluable in simulating different stress scenarios and their impacts on bee colonies. By replicating various environmental and management conditions, we can better understand how different factors interact and influence colony health. This approach allows us to identify robust indicators that can be used in real-world monitoring and management.

Looking Forward: Combining Empirical and Simulation Studies

Our findings underscore the importance of combining empirical studies with simulation models. This integrated approach can accelerate the development of reliable health indicators and improve the assessment of environmental risks to honey bees. Future research should aim at refining these indicators and developing practical monitoring protocols that beekeepers can easily implement.


The VIBEE project is dedicated to advancing our understanding of honey bee health and developing tools to protect these vital pollinators. Our latest research highlights the number of brood cells and the brood-bee ratio as critical early warning signals of colony stress. By focusing on these indicators, we can enhance bee management practices and safeguard bee populations for future generations.


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Groeneveld, Jürgen; Odemer, Richard; Requier, Fabrice

Brood indicators are an early warning signal of honey bee colony loss—a simulation-based study Journal Article

In: PLOS ONE, 2024.

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