The use of β-CDs to improve honey bee health

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Honey bees are essential members of the natural ecosystems and the modern agriculture, yet their colonies are collapsing worldwide. In the U.S., the number of bee colonies has declined by 60 percent between 1947-2008. The bees are dying from a variety of factors, including chemical pesticides and herbicides applied to crops where bees are foraging. Studies show, that these substances can be directly toxic, or just generally weaken a hive.

Neonicotinoids, such as clothianidin and imidacloprid are widely used neuro-active insecticides. These compounds are partially water soluble, meaning they are taken up, and distributed throughout the plant. Honey bees foraging around these plants come in contact with the pollen and nectar, and that, in most cases results in death. Beehives are also treated against parasites with pyrethroids and organoposphates. These are the most common contaminants present in bees and beehive products. Acute dosages of these compounds are not toxic, but the general health of the colony declines.

According to a new invention [1], cyclodextrin (CD) complexes are able to reduce the impacts of chemical exposure on beehives. The composition contains a cyclodextrin, a carrier and optionally vitamins and/or nutrients.

Methyl-b-cyclodextrin (MBCD) and hydroxypropyl-b-cyclodextrin (HPBCD) are being used, which provide good binding to organophosphates, pyrethroids and neonicotinoid pesticides. The treatment of healthy adult worker honey bees with MBCD acts to extend the lifespan of the bees and is absent of any measured negative effects. The bees were fed using a syringe filled with 50% sucrose supplemented with either 1, 10, or 100 pg MBCD per bee/per week. A dosage of 10 pg/bee MBCD provided the greatest protection and surprisingly extended the median lifespan from 32 to 40 days. The upper limit for CD dosage appears to be about 100 pg/bee based on the observed diminishing effects.

About 50% of the colonies that received no extra treatment (only sugar syrup supplements) were lost. The group receiving only Amitraz (the current industry standard for mite control) lost about 20% of the colonies. HPBCD on its own was able to reduce hive loss to about 30%. Surprisingly and unexpectedly, when both Amitraz and HPBCD were combined, no colony losses were observed.

The carrier acts to attract the bees and ensures they feed on the composition. Preferred formulations for the mixture include, for example, honey bee dietary syrup, spray and strips that the bees are able to chew through to access the composition.

The formulation further contains one or more vitamins (vitamin A, D, E, etc.), minerals, nutrients, fat-soluble components that increases the overall well-being of the bees.

The CD-containing compositions are readily consumed by honey bees and provide significant and surprisingly unexpected increases in lifespan as well as a protective effect against potentially harmful biotic and abiotic threats such as pesticides, agrochemicals, viruses, cold weather, and possibly habitat loss and degradation and climate change.

„If the bee disappeared off the face of the Earth, man would only have four years left to live.”

            Albert Einstein

[1]       WO2021011568 – Compositions and methods for improved honey bee health

Photo: Ferenc Medve

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