Question 21M.2.SL.TZ2.f

Honeybees (Apis mellifera) are key pollinators in most ecosystems. The worldwide use of neonicotinoid pesticides has caused concern because they may be contributing to the decline of honeybee populations.

Scientists measured the concentration of five neonicotinoids (acetamiprid, clothianidin, imidacloprid, thiacloprid and thiamethoxam) in honey samples from 198 different locations across the world. Each pie chart shows the relative frequency of neonicotinoids in honey samples from a continent.

[Source: Republished with permission of American Association for the Advancement of Science, from A worldwide survey of neonicotinoids in honey, Mitchell, E.A., et al., Science, Volume 358, Issue 6359, 2017. Permission conveyed through Copyright Clearance Center, Inc. https://science.sciencemag.org/content/358/6359/109.full.]

The neonicotinoids can be used alone or together with other neonicotinoids. The percentage of honey samples with 0, 1, 2, 3, 4 or 5 different neonicotinoids in each continent are shown in the stacked bar chart.

[Source: Republished with permission of American Association for the Advancement of Science, from A worldwide survey of neonicotinoids in honey, Mitchell, E.A., et al., Science, Volume 358, Issue 6359, 2017. Permission conveyed through Copyright Clearance Center, Inc. https://science.sciencemag.org/content/358/6359/109.full.]

In order to grow, honeybee larvae are fed royal jelly, a high energy food with very high acetylcholine concentrations.

In an experiment, larvae were bred artificially on a diet with reduced acetylcholine content in the royal jelly. The graph shows the mean survival rate of these larvae compared to control larvae fed on a normal diet.

[Source: Wessler I, Gärtner H-A, Michel-Schmidt R, Brochhausen C, Schmitz L, Anspach L, et al. (2016) Honeybees Produce Millimolar Concentrations of Non-Neuronal Acetylcholine for Breeding: Possible Adverse Effects of Neonicotinoids. PLOS ONE 11(6):e0156886. doi:10.1371/journal.pone.0156886 Copyright: © 2016 Wessler et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.]

The concentration of acetylcholine was measured in royal jelly produced by honeybees that had never been exposed to neonicotinoids (control) and honeybees that had been exposed for three weeks to two neonicotinoids; clothianidin and thiacloprid.

Wessler I, Gärtner H-A, Michel-Schmidt R, Brochhausen C, Schmitz L, Anspach L, et al. (2016) Honeybees Produce Millimolar Concentrations of Non-Neuronal Acetylcholine for Breeding: Possible Adverse Effects of Neonicotinoids. PLOS ONE 11(6):e0156886. doi:10.1371/journal.pone.0156886 Copyright: © 2016 Wessler et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.