Chronic exposure of honeybees, Apis mellifera (Hymenoptera: Apidae), to a pesticide mixture in realistic field exposure rates

Abstract

Pollen might be contaminated by multiple pesticides representing a risk for long-term contamination of honeybees when collected. Standardized methodology to assess the effects of pesticide mixtures under field conditions is lacking. We conducted an experiment on chronic feeding of a diet contaminated with a field-realistic pesticide mixture on free-flying honeybee colonies. Pesticide residues in larvae and adult tagmata were detected in trace amounts. In colonies treated with a pesticide mixture, larval weight was higher and acini diameters of the hypopharyngeal glands of nurse bees were smaller than in the untreated control. Brood termination and adult lifespan did not differ between both groups. Our study offers a reproducible and applicable approach for testing effects of pesticides on bee health. As feeding of a field-realistic pesticide mixture did not elicit acute bee toxic effects, the described differences might be explained by sub-lethal effects or joint action of single compounds. pesticide combination / field test / long-term uptake / mini hives / multi-residue analysis Electronic supplementary material The online version of this article (

Field-relevant doses of the systemic insecticide fipronil and fungicide pyraclostrobin impair mandibular and hypopharyngeal glands in nurse honeybees (Apis mellifera)

“…However, we observed neither additive nor synergistic effects of pyraclostrobin + fipronil on the development of this gland, likely because of the high reduction of acini area as observed in single-pesticide exposure to fipronil or pyraclostrobin. These data corroborate previous studies showing hypopharyngeal-gland impairment in honeybees exposed to pesticides in the laboratory 35 , 55 – 58 and in bees exposed to pesticides in the field 58 , 59 . As far as we are aware, our study is the first to examine both the mandibular and hypopharyngeal glands in honeybees exposed to pesticides.…”

From field to food—will pesticide-contaminated pollen diet lead to a contamination of royal jelly?

“…For our test, we used substances that are commonly used in agricultural practice and have been found in bee-collected pollen (Genersch et al 2010, Böhme et al 2017. The concentrations chosen are higher than average concentrations regularly found in pollen and bee bread collected from honeybees under field conditions, although there are sometimes reports on peak values from field studies that are in the range of our applied pesticide concentrations (Pettis et al 2013, Rosenkranz et al 2014, Traynor et al 2016.…”

“…On the next day, the colonies were positioned in the spacious garden of the Apicultural State Institute in Stuttgart-Hohenheim and hive entrances were opened again. Two of the colonies were assigned the pesticides group, which were offered 70-g packages of a pollen-honey diet enriched with a mixture of pesticides (commercial products in their respective formulations, Table I) that are commonly found in pollen pellets collected in intensively used agricultural areas in Southern Germany (Böhme et al 2017).…”

“…The objective of this research was to trace possible pesticide residues in RJ back to the protein source. Thus, we designed a field-realistic, yet worst-case trial where we fed a mixture of commonly found pesticides (Böhme et al 2017) mixed in high concentrations into a pollen-honey diet, providing proteins for RJ similar to bee bread. While feeding, we initiated a queen rearing within the colony to obtain RJ, presumably contaminated with the given pesticides, which was subjected to a multi-residue analysis.…”

Multi-dimensional modelling tools supporting decision-making for the beekeeping sector

“…The causes that influence honey bee colony health are multiple (Goulson et al, 2015;) and may be subdivided into 5 categories: (1) chemical exposure (Böhme et al, 2017); (2) diseases and biological agents (Higes et al, 2009); (3) change in land use and landscape fragmentation ; (4) climate change and variability ; (5) beekeeping practices (Jacques et al, 2017).…”