Good nutrition is key to honey bee survival

Honey bees, the diligent workers of fields and gardens, face three major threats – nutritional stress, viral infections, and pesticide exposure.

In a new study conducted at the University of Illinois Urbana-Champaign, researchers have intricately dissected this interconnected network of stressors. Their discovery? Good nutrition boosts honey bee resilience.

Honey bees, stress, and nutrition

“Multiple stressors are often bad for survival,” said graduate student Edward Hsieh, who led the research Professor Adam Dolezal.

“However, it is always context-dependent, and you have to be aware of all these factors when you’re trying to make broad statements about how interactive effects affect honey bees.”

According to Hsieh, most scientific studies focus on just one or two factors at a time. Some may explore the mashup of poor nutrition and pesticide exposure, while others may investigate the union of pesticides and viral infections.

Yet, none have explored how all three stressors together may impact honey bee populations.

Complex mix of pesticides

Even understanding how bees respond to all of the agricultural chemicals they encounter is a complicated task, said Professor Dolezal.

“Some insecticides will work better against some insects than others, but they tend to be more lethal than fungicides or herbicides. Some fungicides, however, are known to make insecticides more toxic to insects,” explained Professor Dolezal.

Exposing bees to chemicals and viruses

For the investigation, caged bees were exposed to different combinations of dietary, viral, and chemical treatments.

The agricultural pesticides used were chlorpyrifos, an organophosphate; lambda-cyhalothrin, a pyrethroid; and thiamethoxam, a neonicotinoid.

The bees were also exposed to the Israeli Acute Paralysis Virus, one of several viruses implicated in the global decline of honey bee colonies.

The role of honey bee nutrition

The experiments led to some surprising results. For example, if bees were fed artificial pollen and exposed to the virus and pesticide, they died in large numbers. However, when the artificial pollen was replaced with natural pollen, the results were very different.

On the natural pollen diet, virus-exposed bees still faced higher mortality. But if they were also exposed to a mixture of chlorpyrifos and a fungicide, surprisingly fewer of them died.

According to Professor Dolezal, it’s as if the bees have an inherent ability to deal with stress, but only if they have the nutritional resources to do so.

The researchers emphasized that this doesn’t mean that chemical exposures are harmless. The findings do not advocate careless use of pesticides. It all depends on the chemical – different pesticides have different molecular targets and exert different effects.

High-quality habitats

The study confirms that creating and maintaining high-quality prairie habitats near agricultural sites can enhance bee resilience.

These habitats are not an “ecological trap,” enticing bees with flowers only to poison them with agricultural chemicals.

According to Dolezal, the study showed that bees are quite resilient even to the interaction of pesticides and viruses if they have good nutrition.

Genetic diversity provides a buffer

In the quest to enhance bee resilience, genetic diversity emerges as a critical factor. The research indicates that colonies with a greater diversity of worker genotypes tend to exhibit more adaptable responses to stressors.

This diversity can buffer against the impact of various threats, providing a genetic toolbox that helps honey bee populations withstand nutritional deficiencies, infections, and pesticide exposures.

By maintaining or even bolstering this genetic diversity, either through selective breeding or preservation of natural wild populations, researchers and conservationists can potentially enhance the adaptability and survival of bees amidst increasing environmental challenges.

Implications for agricultural practices

The insights gained from this study have profound implications for agricultural practices.

Farmers and land managers can adopt bee-friendly approaches, which involve minimizing pesticide applications, selecting compounds with the least potential harm to bees, and timing applications to avoid periods of high bee activity.

Furthermore, incorporating diverse floral resources in agricultural areas can provide essential nutritional supplements to bees.

These sustainable practices not only safeguard bee populations but also benefit agricultural productivity by ensuring the continued provision of pollination services critical for many crops.

Nutrition and honey bee resilience

One thing stands clear – while good nutrition can boost honey bee resilience, it is not a get-out-of-jail-free card for pesticide use. In almost all cases, pesticides (alone or in conjunction with viruses) are harmful to bees.

But in our battle to increase bee resilience, high-quality habitats play a significant role. As Hsieh pointed out, it’s gratifying to know that we can help the bees out, at least a little, by providing them a good habitat.