Bergamot Polyphenolic Fraction for the Control of Flupyradifurone-Induced Poisoning in Honeybees

Abstract

Flupyradifurone (FLU) is a butenolide insecticide that has come onto the market relatively recently. It is used in agriculture to control aphids, psyllids, and whiteflies. Toxicity studies have decreed its low toxicity to honeybees. However, recent research has challenged these claims; oral exposure to the pesticide can lead to behavioral abnormalities and in the worst cases, lethal phenomena. Compounds with antioxidant activity, such as flavonoids and polyphenols, have been shown to protect against the toxic effects of pesticides. The aim of this research was to evaluate the possible protective effect of the bergamot polyphenolic fraction (BPF) against behavioral abnormalities and lethality induced by toxic doses of FLU orally administered to honeybees under laboratory conditions. Honeybees were assigned to experimental groups in which two toxic doses of FLU, 50 mg/L and 100 mg/L were administered. In other replicates, three doses (1, 2 and 5 mg/kg) of the bergamot polyphenolic fraction (BPF) were added to the above toxic doses. In the experimental groups intoxicated with FLU at the highest dose tested, all caged subjects (20 individuals) died within the second day of administration. The survival probability of the groups to which the BPF was added was compared to that of the groups to which only the toxic doses of FLU were administered. The mortality rate in the BPF groups was statistically lower (p < 0.05) than in the intoxicated groups; in addition, a lower percentage of individuals exhibited behavioral abnormalities. According to this research, the ingestion of the BPF attenuates the harmful effects of FLU. Further studies are needed before proposing BPF incorporation into the honeybees' diet, but there already seem to be beneficial effects associated with its intake.

Keywords: animal health and welfare; bergamot (Citrus bergamia Risso et Poiteau) bergamot polyphenolic fraction (BPF); flupyradifurone; honeybee (Apis mellifera); natural products; poisoning.

Figure 1

Survival graph. CTRL: control; BPF: bergamot polyphenolic fraction; FLU: flupyradifurone. BPF 1 vs. CTRL: p value > 0.05; BPF 2 vs. CTRL: p value > 0.05; BPF 5 vs. CTRL: p value > 0.05; FLU 50 vs. CTRL: p value < 0.001; FLU 100 vs. CTRL: p value < 0.001; FLU 100 vs. FLU 50: p value < 0.001; FLU 50 + BPF 1 vs. FLU 50: p value < 0.05; FLU 50 + BPF 2 vs. FLU 50: p value < 0.05; FLU 50 + BPF 5 vs. FLU 50: p value < 0.05; FLU 100 + BPF 1 vs. FLU 100: p value < 0.001; FLU 100 + BPF 2 vs. FLU 100: p value < 0.001; FLU 100 + BPF 5 vs. FLU 100: p value < 0.001.

Figure 2

Abnormal behavior. CTRL: control; BPF: bergamot polyphenolic fraction; FLU: flupyradifurone. *** p value < 0.001 vs. CTRL; ## p value < 0.01 vs. FLU 50; ### p value < 0.01 vs. FLU 50; ^^ p value < 0.01 vs. FLU 100.

Figure 3

Treatment consumption. CTRL: control; BPF: bergamot polyphenolic fraction; FLU: flupyradifurone. ** p value < 0.01 vs. CTRL; *** p value < 0.001 vs. CTRL; ## p value < 0.01 vs. FLU 50; ### p value < 0.001 vs. FLU 50; ^^ p value < 0.001 vs. FLU 100.