Translocation of Tebuconazole between Bee Matrices and Its Potential Threat on Honey Bee (Apis mellifera Linnaeus) Queens.

Risto Raimets,Reet Karise,Marika Mänd,Sigmar Naudi,Guy Smagghe,Vadims Bartkevičs

doi:10.3390/insects13010045

Abstract

Simple SummaryNumerous pesticide residues have been found in bee products. It is unclear whether and to what degree pesticides migrate between different bee matrices. Even though the use of many common insecticides is strictly regulated, fungicide residues are still ubiquitous in bee matrices and data regarding this problem are still insufficient. The aim of this work was to determine the migration of fungicide tebuconazole between bee matrices and to assess its potential risk to honey bee queens. We found that tebuconazole mixed into wax has the potential to migrate into royal jelly (RJ), but no residues were found in honey bee queen larvae and newly emerged queens. The residues of tebuconazole found in queen cell cups and RJ decreased over time and probably posed no direct lethal threat to queens. Nevertheless, sub-lethal effects of tebuconazole on honey bee queens might occur even at low concentrations.Various pesticide residues can be found in different bee colony components. The queen larvae of honey bee (Apis mellifera L.) receive non-contaminated food from nurse bees. However, there is little knowledge about how pesticide residues affect developing bees. Additionally, little is known about the migration of lipophilic pesticides between bee matrices. While wax, royal jelly (RJ), and bee larvae are chemically distinct, they all contain lipids and we expected the lipophilic fungicide tebuconazole to be absorbed by different contacting materials. Our aim was to analyze the translocation of tebuconazole residues from queen cell wax to RJ, queen larvae, and newly emerged queens and to evaluate its potential risk to queens. We demonstrated the potential for the migration of tebuconazole from wax to RJ, with a strong dilution effect from the original contamination source. No residues were detected in queen bee larvae and newly emerged queens, indicating that the migration of tebuconazole probably did not directly endanger the queen bee, but there was some risk that tebuconazole might still affect the homeostasis of developing bees.

Highlights

Pesticides are known to be amplify all stress elements related to honey bee colony losses [1]
Tebuconazole residues were found in the entire queen cell wax (0.19 mg kg−1 ), indicating that this substance was incorporated into wax during the experiment
The tebuconazole concentration found in royal jelly (RJ) was 0.08 mg kg−1 (0.08 μg per bee), which was 2.4 times lower than found in wax and probably should not pose a risk to the survival of honey bee queens

Summary

Introduction

Pesticides are known to be amplify all stress elements related to honey bee colony losses [1]. Various pesticides accumulate in different bee products [2,3] and often beeswax is the most contaminated bee product [3–5]. Most of the conducted studies have been focused on insecticide effects on bees, while fungicides have gained little attention. It has been shown that at least azole type fungicides can potentiate the toxicity of insecticides [6–8]. Tebuconazole is very commonly used and its residues have been found in bee matrices [2,10,11]. Tebuconazole has synergistic negative effects on honey bees together with insecticides [10]. It can separately affect microbial communities in different environments, including those in insect guts [11,12]

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