Hungry bees: How limited food affects bee behavior and health

Greg Howard
18th January, 2026

Hungry bees: How limited food affects bee behavior and health

Western Honey Bee (Apis mellifera)

Photo adapted from: Gavin Slater / CC BY (Source)

Key Findings

  • Honey bee colonies in Louisiana exhibited increased defensive behavior when pollen availability was experimentally reduced for five weeks
  • Larval exposure to pollen deprivation appeared to prime adult bees, influencing gene expression related to defensiveness, specifically Cyp6g1/2
  • Changes in colony defense correlated with alterations in gene expression, particularly GB53860, and physiological markers like hypopharyngeal gland size
Nutritional stress is a growing concern for honey bee populations, contributing to colony decline through increased mortality, weakened immune systems, and altered behaviours. Honey bees rely on pollen as their primary protein source, and periods of pollen scarcity – known as pollen dearths – can significantly impact colony health. Researchers at the USDA-ARS recently investigated how realistic protein deficiency affects honey bee behaviour and physiology[1]. This study aimed to determine if limited pollen availability leads to changes in bee temperament and, importantly, how these changes manifest at the individual and colony levels. The research team simulated a pollen dearth in half of their experimental bee colonies by preventing incoming foragers from depositing pollen at the hive entrance. This effectively reduced the protein intake for the entire colony. They then monitored the temperament of each colony weekly, comparing the behaviour of pollen-deprived bees to a control group with normal pollen access. In addition to behavioural observations, the researchers identified the plant species the bees were foraging from and measured various physiological indicators of nutritional status, including the size of specific glands, lipid (fat) levels, and gene expression patterns within the bees. The study revealed that colonies experiencing pollen deprivation exhibited a marked increase in defensive behaviour. This finding builds upon earlier work highlighting the critical role of bees in agriculture[2], as stressed colonies may become less effective pollinators due to altered foraging patterns and increased aggression. Interestingly, the researchers found that the effects of nutritional stress weren't limited to adult bees. Immature bees appeared to receive cues during their development – likely through the food they were fed by nurse bees – that primed their gene expression and subsequent behaviour as adults. This suggests that environmental stressors can induce long-lasting changes in bee behaviour, even before they emerge from their cells. This observation is particularly intriguing when considered alongside research into the division of labour within honey bee colonies[3]. That study demonstrated how bees specialize in different tasks, such as guarding the hive or foraging for food, and how these roles are influenced by both genetics and environmental factors. The current study suggests that nutritional stress may alter the developmental pathways that determine these roles, potentially leading to a higher proportion of defensive bees within a colony. A key question in bee behavioural research is the relative contribution of genetics versus environment. While temperament is often linked to an individual bee’s genotype, these new findings demonstrate the significant, and often underestimated, impact of environmental cues. This study serves to bridge a gap left by historical work, such as genome-wide association studies (GWAS) previously conducted by members of the same research group. One earlier study revealed that colony-level aggression was strongly correlated with the frequency of specific alleles (versions of genes) within the colony, but individual aggression did not show a clear link to specific alleles[4]. While past studies suggested that collective behaviour is strongly determined by genetic makeup, the current research highlights that environmental context, specifically nutrition, is a critical variable that can dramatically shift these behavioural outcomes. Complementing this genetic perspective, related research using single-cell transcriptomics has helped pinpoint changes in brain gene regulation as a key mechanism driving behavioural differences[5]. This separate analysis identified hundreds of genes associated with colony aggression, specifically noting that the regulatory dynamics of genes involved in olfaction (sense of smell) and vision were altered in bees from more aggressive colonies. The current study builds on this biological framework, demonstrating that nutritional stress is a powerful external factor capable of modulating similar gene expression profiles and triggering defensive states. The findings of this new study tie together these previous works by demonstrating how environmental stress can modulate individual brain gene regulatory networks, ultimately shaping collective behaviour. The observed changes in gene expression and behaviour are likely a result of altered resource availability and the resulting impact on colony genetics and individual development. As droughts become more frequent and resource availability changes over time, understanding these complex interactions is crucial for developing effective management practices to support honey bee populations.

AgricultureEcologyAnimal Science

References

Main Study

1) Hangry bees: Pollen dearth impacts honey bee (Apis mellifera) behavior and physiology

Published 16th January, 2026

https://doi.org/10.1371/journal.pone.0338712

Related Studies

2) Overview of Bee Pollination and Its Economic Value for Crop Production.

https://doi.org/10.3390/insects12080688

3) Division of labour during honeybee colony defence: poetic and scientific views.

https://doi.org/10.1098/rstb.2023.0272

4) Genomic regions influencing aggressive behavior in honey bees are defined by colony allele frequencies.

https://doi.org/10.1073/pnas.1922927117

5) Single-cell dissection of aggression in honeybee colonies.

https://doi.org/10.1038/s41559-023-02090-0


Related Articles

An unhandled error has occurred. Reload 🗙