Pesticides Harm Royal Jelly.

Green for 2024.

Green is the in colour for queens this year. I still have a couple from the end of last season’s production to mark with red paint. I’ve been caught out in the past by marking queens late in the season and finding that the colonies were not accepting of this. As soon as the marked queens started laying eggs supersedure cells and queens were produced. A couple of times, the newest queens didn’t get mated in time for winter so I’m not doing that again. Queens have a hard enough time without coming up against poor beekeeping decisions.

Chemical Damage.

A couple of weeks ago Dr Bee from Inside The HiveTV presented some interesting new findings on the effects of pesticides on royal jelly and the bad news for developing queens https://youtu.be/xNaeifZMOmA. We already know that what happens in early life can greatly affect health outcomes and disease in later life. Chemical exposure to human foetuses in utero has been well documented and most people remember the shocking limb deformities in newborn babies resulting from pregnant mothers being given a sedative drug called thalidomide in the 1950s and 60’s to prevent morning sickness and excessive vomiting in pregnancy (hyperemesis gravidarum). Thalidomide is still used today but for cancer treatment and never during pregnancy.

We know a lot about how pesticides affect honey bees, but not everything. Acute poisoning might present as a pile of dead bees outside a hive, or more subtly as the gradual dwindling of a colony as foragers suffer neurological damage and forget how to navigate back to the hive. The signs of sublethal pesticide exposure are usually not so obvious and it is easy to forget about them when not faced with dead bees. There is often ignorance around fungicide use because some people don’t understand the role of a healthy bee gut biome and how fungicides can kill the good bacteria and compromise honey bee immunity.

Recently an experienced beekeeper friend called me to tell me about a big council project in his home city to plant a wildflower meadow. Ironically, to clear the ground to plant for pollinators the council decided to use a glyphosate product though it is known to be brought back to the hive by foragers and incorporated into brood food with negative results for developing brood. Fortunately, the particular council is open to discussing alternative methods of preparing the ground. My friend is working with them to try for a better alternative solution.

Oral Pesticide Exposure.

Milone et al.¹ published a study that investigated oral pesticide exposure in honey bees. Previous work found that there is a very low level of pesticides transferred to royal jelly but the Milone study hypothesized that the pesticides detected in the commercial colonies, chosen for study, can influence royal jelly composition and production.

A mixture of nine pesticides included Atrazine, Carbaryl, Coumaphos, and fluvalinate was fed to the test colonies. The chemical cocktail comprised 2 miticides, 2 fungicides, 2 herbicides, and 3 insecticides. The researchers discovered that pesticides did indeed negatively impact the nutritional composition of royal jelly and this was more marked than the quantity and weight of royal jelly in each cell which were not significantly different from the control colonies.

Pesticide ingestion led to degeneration of nurse bees’ brood food producing hypopharyngeal glands which had an indirect effect on queen development. In the treated colonies there was a lower amount of phytosterols which are really important plant sterols and the key lipid component in honey bee nutrition. Sterols are subgroup of steroids and phytosterols are a cholesterol-like compound found in many plant based foods. Humans use plant sterols for lowering cholersterol and treating heart disease and cancers. There was also a reduction in the major royal jelly proteins in the treated colonies.

Royal Jelly.

Larval queens need royal jelly during the development stage and it is their only source of nutrition, unlike worker bees that are fed royal jelly for the first three days then a mixture of glandular secretions and pollen. It has been shown in previous studies that nurse bees can buffer chemical residues but this recent work shows clearly the damage caused by chemicals and how important queen-making components such as 10-hydroxy-2-decenoic acid and other main royal jelly components were reduced and negatively influenced queen development. This is the first study to show how colony level pesticide exposure can influence queen development and it is another piece of the puzzle of queen failure in our time.

As beekeepers, the more we understand about these complex chemicals the better we can care for our bees. We can reduce our own use of chemicals and negotiate with local councils, farmers, etc, to reduce their use, or give us warning of treatments so that we can protect our bees. However, firstly we need to be out there meeting the stakeholders and being aware of local forage and what is going on in our neighbourhoods regarding chemical treatments.

¹Joseph P. Milone, Priyadarshini Chakrabarti, Ramesh R. Sagili, & David R. Tarpy (2021) Colony-level pesticide exposure affects honey bee (Apis mellifera L.) royal jelly production and nutritional composition, Chemosphere 263 (2021) 128183  https://doi.org/10.1016/j.chemosphere.2020.128183