Acute and chronic toxicity of imidacloprid in the pollinator fly, Eristalis tenax L., assessed using a novel oral bioassay
Imidacloprid is a neonicotinoid neurotoxin that remains widely used worldwide and persists in the environment, resulting in chronic exposure to non-target insects. To accurately map dose-dependent effects of such exposure across taxa, toxicological assays need to assess relevant modes of exposure ac...
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| Format: | Article |
| Language: | English |
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Elsevier
2023-02-01
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| Series: | Ecotoxicology and Environmental Safety |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S014765132300009X |
| _version_ | 1797936426426302464 |
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| author | Nicolas Nagloo Elisa Rigosi David C. O’Carroll |
| author_facet | Nicolas Nagloo Elisa Rigosi David C. O’Carroll |
| author_sort | Nicolas Nagloo |
| collection | DOAJ |
| description | Imidacloprid is a neonicotinoid neurotoxin that remains widely used worldwide and persists in the environment, resulting in chronic exposure to non-target insects. To accurately map dose-dependent effects of such exposure across taxa, toxicological assays need to assess relevant modes of exposure across indicator species. However, due to the difficulty of these experiments, contact bioassays are most frequently used to quantify dose. Here, we developed a novel naturalistic feeding bioassay to precisely measure imidacloprid ingestion and its toxicity for acute and chronic exposure in a dipteran, Eristalis tenax L., an important member of an under-represented pollinator group. Flies which ingested imidacloprid dosages lower than 12.1 ng/mg all showed consistent intake volumes and learned improved feeding efficiency over successive feeding sessions. In contrast, at doses of 12.1 ng/mg and higher flies showed a rapid onset of severe locomotive impairment which prevented them from completing the feeding task. Neither probability of survival nor severe locomotive impairment were significantly higher than the control group until doses of 1.43 ng/mg or higher were reached. We were unable to measure a median lethal dose for acute exposure (72 h) due to flies possessing a relatively high tolerance for imidacloprid. However, with chronic exposure (18 days), mortality went up and an LD50 of 0.41 ng/mg was estimated. Severe locomotive impairment (immobilisation) tended to occur earlier and at lower dosages than lethality, with ED50s of 7.82 ng/mg and 0.17 ng/mg for acute and chronic exposure, respectively. We conclude that adult Eristalis possess a much higher tolerance to this toxin than the honeybees that they mimic. The similarity of the LD50 to other dipterans such as the fruitfly and the housefly suggests that there may be a phylogenetic component to pesticide tolerance that merits further investigation. The absence of obvious adverse effects at sublethal dosages also underscores a need to develop better tools for quantifying animal behaviour to evaluate the impact of insecticides on foraging efficiency in economically important species. |
| first_indexed | 2024-04-10T18:29:31Z |
| format | Article |
| id | doaj.art-14cd57b0b9794fd7941f2aa1104c710f |
| institution | Directory Open Access Journal |
| issn | 0147-6513 |
| language | English |
| last_indexed | 2024-04-10T18:29:31Z |
| publishDate | 2023-02-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Ecotoxicology and Environmental Safety |
| spelling | doaj.art-14cd57b0b9794fd7941f2aa1104c710f2023-02-02T04:46:52ZengElsevierEcotoxicology and Environmental Safety0147-65132023-02-01251114505Acute and chronic toxicity of imidacloprid in the pollinator fly, Eristalis tenax L., assessed using a novel oral bioassayNicolas Nagloo0Elisa Rigosi1David C. O’Carroll2Correspondence to: Department of Biology, Lund University, Sölvegatan 35, Lund S-22362, Sweden.; Department of Biology Lund University, Lund, SwedenDepartment of Biology Lund University, Lund, SwedenDepartment of Biology Lund University, Lund, SwedenImidacloprid is a neonicotinoid neurotoxin that remains widely used worldwide and persists in the environment, resulting in chronic exposure to non-target insects. To accurately map dose-dependent effects of such exposure across taxa, toxicological assays need to assess relevant modes of exposure across indicator species. However, due to the difficulty of these experiments, contact bioassays are most frequently used to quantify dose. Here, we developed a novel naturalistic feeding bioassay to precisely measure imidacloprid ingestion and its toxicity for acute and chronic exposure in a dipteran, Eristalis tenax L., an important member of an under-represented pollinator group. Flies which ingested imidacloprid dosages lower than 12.1 ng/mg all showed consistent intake volumes and learned improved feeding efficiency over successive feeding sessions. In contrast, at doses of 12.1 ng/mg and higher flies showed a rapid onset of severe locomotive impairment which prevented them from completing the feeding task. Neither probability of survival nor severe locomotive impairment were significantly higher than the control group until doses of 1.43 ng/mg or higher were reached. We were unable to measure a median lethal dose for acute exposure (72 h) due to flies possessing a relatively high tolerance for imidacloprid. However, with chronic exposure (18 days), mortality went up and an LD50 of 0.41 ng/mg was estimated. Severe locomotive impairment (immobilisation) tended to occur earlier and at lower dosages than lethality, with ED50s of 7.82 ng/mg and 0.17 ng/mg for acute and chronic exposure, respectively. We conclude that adult Eristalis possess a much higher tolerance to this toxin than the honeybees that they mimic. The similarity of the LD50 to other dipterans such as the fruitfly and the housefly suggests that there may be a phylogenetic component to pesticide tolerance that merits further investigation. The absence of obvious adverse effects at sublethal dosages also underscores a need to develop better tools for quantifying animal behaviour to evaluate the impact of insecticides on foraging efficiency in economically important species.http://www.sciencedirect.com/science/article/pii/S014765132300009XImidaclopridToxicological assayLD50Chronic exposureAcute exposureLocomotion |
| spellingShingle | Nicolas Nagloo Elisa Rigosi David C. O’Carroll Acute and chronic toxicity of imidacloprid in the pollinator fly, Eristalis tenax L., assessed using a novel oral bioassay Ecotoxicology and Environmental Safety Imidacloprid Toxicological assay LD50 Chronic exposure Acute exposure Locomotion |
| title | Acute and chronic toxicity of imidacloprid in the pollinator fly, Eristalis tenax L., assessed using a novel oral bioassay |
| title_full | Acute and chronic toxicity of imidacloprid in the pollinator fly, Eristalis tenax L., assessed using a novel oral bioassay |
| title_fullStr | Acute and chronic toxicity of imidacloprid in the pollinator fly, Eristalis tenax L., assessed using a novel oral bioassay |
| title_full_unstemmed | Acute and chronic toxicity of imidacloprid in the pollinator fly, Eristalis tenax L., assessed using a novel oral bioassay |
| title_short | Acute and chronic toxicity of imidacloprid in the pollinator fly, Eristalis tenax L., assessed using a novel oral bioassay |
| title_sort | acute and chronic toxicity of imidacloprid in the pollinator fly eristalis tenax l assessed using a novel oral bioassay |
| topic | Imidacloprid Toxicological assay LD50 Chronic exposure Acute exposure Locomotion |
| url | http://www.sciencedirect.com/science/article/pii/S014765132300009X |
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