Mixture effects of thiamethoxam and seven pesticides with different modes of action on honey bees (Aplis mellifera)

Abstract

Even though honey bees in the field are routinely exposed to a complex mixture of many different agrochemicals, few studies have surveyed toxic effects of pesticide mixtures on bees. To elucidate the interactive actions of pesticides on crop pollinators, we determined the individual and joint toxicities of thiamethoxam (THI) and other seven pesticides [dimethoate (DIM), methomyl (MET), zeta-cypermethrin (ZCY), cyfluthrin (CYF), permethrin (PER), esfenvalerate (ESF) and tetraconazole (TET)] to honey bees (Aplis mellifera) with feeding toxicity test. Results from the 7-days toxicity test implied that THI elicited the highest toxicity with a LC50 data of 0.25 (0.20–0.29) μg mL−1, followed by MET and DIM with LC50 data of 4.19 (3.58–4.88) and 5.30 (4.65–6.03) μg mL−1, respectively. By comparison, pyrethroids and TET possessed relatively low toxicities with their LC50 data from the range of 33.78 (29.12–38.39) to 1125 (922.4–1,442) μg mL−1. Among 98 evaluated THI-containing binary to octonary mixtures, 29.59% of combinations exhibited synergistic effects. In contrast, 18.37% of combinations exhibited antagonistic effects on A. mellifera. Moreover, 54.8% pesticide combinations incorporating THI and TET displayed synergistic toxicities to the insects. Our findings emphasized that the coexistence of several pesticides might induce enhanced toxicity to honey bees. Overall, our results afforded worthful toxicological information on the combined actions of neonicotinoids and current-use pesticides on honey bees, which could accelerate farther comprehend on the possible detriments of other pesticide mixtures in agro-environment.

Toxic effects of bisphenol analogues and their mixture on two freshwater algae Chlorella vulgaris and Desmodesmus armatus

“…Based on EC 50 values, the overall toxicity ranking is MIX>BPPH>BPB>BPC>BPFL>BPF>BPE for C. vulgaris and BPB>MIX>BPFL>BPC>BPPH>BPE>BPF for D. armatus. by Elersek et al (2021), in their studies observing that BPF (EC 50 (3 day): 9.2 mg L -1 ) was less toxic than BPA (EC 50 (3 day): 6.8 mg L -1 ) to Pseudokirchneriella subcapitata (Elersek et al 2021) (synergistic, additive, or antagonistic effects) between these pollutants is very important since determining the toxic effects of only single substances may underestimate the actual risk to the ecosystems (Czarny-Krzyminska et al 2023;Li et al 2023). Unfortunately, even though green algae are simultaneously exposed to complex combinations of many different bisphenol analogs, only a few research have studied the harmful effects of their mixtures on these microorganisms.…”

Laboratory Determination of Particulate‐Matter–Bound Agrochemical Toxicity among Honeybees, Mason Bees, and Painted Lady Butterflies

“…Many research reports have detailed the lethal and sublethal toxic effects on insects of a variety of chemicals used in agriculture (Ansell et al, 2021;Bargar et al, 2020;Heller et al, 2020;Hladik et al, 2016;Ingram et al, 2015;Longing et al, 2020;Lv et al, 2023;Peterson et al, 2021a;Sandrock et al, 2014;Weaving et al, 2020;Zhao et al, 2020;Zhu et al, 2014). In terms of the present study, pyrethroids, neonicotinoids, and macrocyclic lactones are toxic to pollinators (see Li et al, 2023;Lv et al, 2023;Peterson et al, 2019;Peterson et al, 2021a). Insect toxicity data for agrochemicals are typically generated using standardized testing methods such as acute contact or oral tests (see Organisation for Economic Co-operation and Development [OECD], 1998) wherein an individual agrochemical is applied directly to a test organism or its food source.…”

Electrochemical Processes Used to Degrade Thiamethoxam in Water and Toxicity Analyses in Non-Target Organisms

“…Thiamethoxam (TMX) is a systemic neonicotinoid insecticide (the first second-generation neonicotinoid pesticide) that is used on several crops in Brazil and worldwide. In a similar manner to other neonicotinoids, its toxicity toward pollinating agents, such as bees, has been widely discussed in the literature; it is associated with disorders observed in the entire population, with harmful consequences for agriculture and species survival [1][2][3][4][5]. TMX has the potential to induce a variety of behavioral difficulties in foraging honeybees, including memory and learning dysfunction and altered navigational skills, even at sublethal doses (i.e., doses that do not lead to direct mortality) [2].…”

“…Accordingly, the individual and joint toxicities of TMX and seven other pesticides toward bees have been analyzed to elucidate how the combined actions of pesticides affect crop pollinators. Seven-day food toxicity testing revealed that TMX exhibited the greatest toxicity, with an LC 50 of 0.25 µg mL −1 [3].…”