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Röder N, Stoll VS, Jupke JF, Kolbenschlag S, Bundschuh M, Theißinger K, Schwenk K. How non-target chironomid communities respond to mosquito control: Integrating DNA metabarcoding and joint species distribution modelling. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 913:169735. [PMID: 38163597 DOI: 10.1016/j.scitotenv.2023.169735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 11/26/2023] [Accepted: 12/26/2023] [Indexed: 01/03/2024]
Abstract
The conservation and management of riparian ecosystems rely on understanding the ecological consequences of anthropogenic stressors that impact natural communities. In this context, studies investigating the effects of anthropogenic stressors require reliable methods capable of mapping the relationships between taxa occurrence or abundance and environmental predictors within a spatio-temporal framework. Here, we present an integrative approach using DNA metabarcoding and Hierarchical Modelling of Species Communities (HMSC) to unravel the intricate dynamics and resilience of chironomid communities exposed to Bacillus thuringiensis var. israelensis (Bti). Chironomid emergence was sampled from a total of 12 floodplain pond mesocosms, half of which received Bti treatment, during a 16-week period spanning spring and summer of 2020. Subsequently, we determined the community compositions of chironomids and examined their genus-specific responses to the Bti treatment, considering their phylogenetic affiliations and ecological traits of the larvae. Additionally, we investigated the impact of the Bti treatment on the body size distribution of emerging chironomids. Our study revealed consistent responses to Bti among different chironomid genera, indicating that neither phylogenetic affiliations nor larval feeding strategies significantly contributed to the observed patterns. Both taxonomic and genetic diversity were positively correlated with the number of emerged individuals. Furthermore, our findings demonstrated Bti-related effects on chironomid body size distribution, which could have relevant implications for size-selective terrestrial predators. Hence, our study highlights the value of employing a combination of DNA metabarcoding and HMSC to unravel the complex dynamics of Bti-related non-target effects on chironomid communities. The insights gained from this integrated framework contribute to our understanding of the ecological consequences of anthropogenic stressors and provide a foundation for informed decision-making regarding the conservation and management of riparian ecosystems.
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Affiliation(s)
- Nina Röder
- iES - Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany.
| | - V Sophie Stoll
- iES - Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany
| | - Jonathan F Jupke
- iES - Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany
| | - Sara Kolbenschlag
- iES - Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany
| | - Mirco Bundschuh
- iES - Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany; Department of Aquatic Science and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Kathrin Theißinger
- LOEWE Centre for Translational Biodiversity Genomics, Senckenberg Biodiversity and Climate Research Centre, Frankfurt am Main, Germany
| | - Klaus Schwenk
- iES - Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany; LOEWE Centre for Translational Biodiversity Genomics, Senckenberg Biodiversity and Climate Research Centre, Frankfurt am Main, Germany
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Schulz R, Bundschuh M, Entling MH, Jungkunst HF, Lorke A, Schwenk K, Schäfer RB. A synthesis of anthropogenic stress effects on emergence-mediated aquatic-terrestrial linkages and riparian food webs. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 908:168186. [PMID: 37914130 DOI: 10.1016/j.scitotenv.2023.168186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 10/23/2023] [Accepted: 10/27/2023] [Indexed: 11/03/2023]
Abstract
Anthropogenic stress alters the linkage between aquatic and terrestrial ecosystems in various ways. Here, we review the contemporary literature on how alterations in aquatic systems through environmental pollution, invasive species and hydromorphological changes carry-over to terrestrial ecosystems and the food webs therein. We consider both the aquatic insect emergence and flooding as pathways through which stressors can propagate from the aquatic to the terrestrial system. We specifically synthesize and contextualize results on the roles of pollutants in the emergence pathway and their top-down consequences. Our review revealed that the emergence and flooding pathway are only considered in isolation and that the overall effects of invasive species or pollutants on food webs at the water-land interface require further attention. While very few recent studies looked at invasive species, a larger number of studies focused on metal transfer compared to pesticides, pharmaceuticals or PCBs, and multiple stress studies up to now left aquatic-terrestrial linkages unconsidered. Recent research on pollutants and emergence used aquatic-terrestrial mesocosms to elucidate the effects of aquatic stressors such as the mosquito control agent Bti, metals or pesticides to understand the effects on riparian spiders. Quality parameters, such as the structural and functional composition of emergent insect communities, the fatty acid profiles, yet also the composition of pollutants transferred to land prove to be important for the effects on riparian spiders. Process-based models including quality of emergence are useful to predict the resulting top-down directed food web effects in the terrestrial recipient ecosystem. In conclusion, we present and recommend a combination of empirical and modelling approaches in order to understand the complexity of aquatic-terrestrial stressor propagation and its spatial and temporal variation.
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Affiliation(s)
- Ralf Schulz
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany.
| | - Mirco Bundschuh
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany; Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Martin H Entling
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany
| | - Hermann F Jungkunst
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany
| | - Andreas Lorke
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany
| | - Klaus Schwenk
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany
| | - Ralf B Schäfer
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany
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3
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Kolbenschlag S, Gerstle V, Eberhardt J, Bollinger E, Schulz R, Brühl CA, Bundschuh M. A temporal perspective on aquatic subsidy: Bti affects emergence of Chironomidae. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 250:114503. [PMID: 36610297 DOI: 10.1016/j.ecoenv.2023.114503] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 11/05/2022] [Accepted: 01/02/2023] [Indexed: 06/17/2023]
Abstract
Emerging aquatic insects serve as one link between aquatic and adjacent riparian food webs via the flux of energy and nutrients. These insects provide high-quality subsidy to terrestrial predators. Thus, any disturbance of emergence processes may cascade to higher trophic levels and lead to effects across ecosystem boundaries. One stressor with potential impact on non-target aquatic insects, especially on non-biting midges (Diptera: Chironomidae), is the widely used mosquito control agent Bacillus thuringiensis var. israelensis (Bti). In a field experiment, we investigated emerging insect communities from Bti-treated (three applications, maximum field rate) and control floodplain pond mesocosms (FPMs) over 3.5 months for changes in their composition, diversity as well as the emergence dynamics and the individual weight of emerged aquatic insects over time. Bti treatments altered community compositions over the entire study duration - an effect mainly attributed to an earlier (∼10 days) and reduced (∼26%) peak in the emergence of Chironomidae, the dominant family (88% of collected individuals). The most reasonable explanation for this significant alteration is less resource competition caused by a decrease in chironomid larval density due to lethal effects of Bti. This is supported by the higher individual weight of Chironomidae emerging from treated FPMs (∼21%) during Bti application (April - May). A temporal shift in the emergence dynamics can cause changes in the availability of prey in linked terrestrial ecosystems. Consequently, terrestrial predators may be affected by a lack of appropriate prey leading to bottom-up and top-down effects in terrestrial food webs. This study indicates the importance of a responsible and elaborated use of Bti and additionally, highlights the need to include a temporal perspective in evaluations of stressors in aquatic-terrestrial meta-ecosystems.
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Affiliation(s)
- Sara Kolbenschlag
- iES Landau, Institute for Environmental Sciences, University of Kaiserslautern-Landau (RPTU), Fortstr. 7, D-76829 Landau, Germany
| | - Verena Gerstle
- iES Landau, Institute for Environmental Sciences, University of Kaiserslautern-Landau (RPTU), Fortstr. 7, D-76829 Landau, Germany
| | - Julian Eberhardt
- iES Landau, Institute for Environmental Sciences, University of Kaiserslautern-Landau (RPTU), Fortstr. 7, D-76829 Landau, Germany
| | - Eric Bollinger
- iES Landau, Institute for Environmental Sciences, University of Kaiserslautern-Landau (RPTU), Fortstr. 7, D-76829 Landau, Germany
| | - Ralf Schulz
- iES Landau, Institute for Environmental Sciences, University of Kaiserslautern-Landau (RPTU), Fortstr. 7, D-76829 Landau, Germany; Eußerthal Ecosystem Research Station, University of Kaiserslautern-Landau (RPTU), Birkenthalstr. 13, D-76857 Eußerthal, Germany
| | - Carsten A Brühl
- iES Landau, Institute for Environmental Sciences, University of Kaiserslautern-Landau (RPTU), Fortstr. 7, D-76829 Landau, Germany
| | - Mirco Bundschuh
- iES Landau, Institute for Environmental Sciences, University of Kaiserslautern-Landau (RPTU), Fortstr. 7, D-76829 Landau, Germany; Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Lennart Hjelms väg 9, SWE-75007 Uppsala, Sweden.
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Gerstle V, Manfrin A, Kolbenschlag S, Gerken M, Islam ASMMU, Entling MH, Bundschuh M, Brühl CA. Benthic macroinvertebrate community shifts based on Bti-induced chironomid reduction also decrease Odonata emergence. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 316:120488. [PMID: 36306884 DOI: 10.1016/j.envpol.2022.120488] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 10/15/2022] [Accepted: 10/17/2022] [Indexed: 06/16/2023]
Abstract
Chironomid larvae (Diptera: Chironomidae) often dominate aquatic macroinvertebrate communities and are a key food source for many aquatic predators, such as dragonfly and damselfly larvae (Odonata). Changes in aquatic macroinvertebrate communities may propagate through terrestrial food webs via altered insect emergence. Bacillus thuringiensis israelensis (Bti)-based larvicides are widely used in mosquito control but can also reduce the abundance of non-biting chironomid larvae. We applied the maximum field rate of Bti used in mosquito control three times to six mesocosms in a replicated floodplain pond mesocosm (FPM) system in spring for two consecutive years, while the remaining six FPMs were untreated. Three weeks after the third Bti application in the first year, we recorded on average a 41% reduction of chironomid larvae in Bti-treated FPMs compared to untreated FPMs and a shift in benthic macroinvertebrate community composition driven by the reduced number of chironomid, Libellulidae and Coenagrionidae larvae (Odonata). Additionally, the number of emerging Libellulidae (estimated by sampling of exuviae in the second year) was reduced by 54% in Bti-treated FPMs. Since Odonata larvae are not directly susceptible to Bti, our results suggest indirect effects due to reduced prey availability (i.e., chironomid larvae) or increased intraguild predation. As Libellulidae include species of conservation concern, the necessity of Bti applications to their habitats, e.g. floodplains, should be carefully evaluated.
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Affiliation(s)
- Verena Gerstle
- Institute for Environmental Sciences, iES Landau, University of Koblenz-Landau, Fortstraße 7, D-76829, Landau, Germany.
| | - Alessandro Manfrin
- Institute for Environmental Sciences, iES Landau, University of Koblenz-Landau, Fortstraße 7, D-76829, Landau, Germany
| | - Sara Kolbenschlag
- Institute for Environmental Sciences, iES Landau, University of Koblenz-Landau, Fortstraße 7, D-76829, Landau, Germany
| | - Maximilian Gerken
- Institute for Environmental Sciences, iES Landau, University of Koblenz-Landau, Fortstraße 7, D-76829, Landau, Germany; Eußerthal Ecosystem Research Station, University of Koblenz-Landau, Birkenthalstraße 13, D-76857, Eußerthal, Germany
| | - A S M Mufachcher Ul Islam
- Institute for Environmental Sciences, iES Landau, University of Koblenz-Landau, Fortstraße 7, D-76829, Landau, Germany
| | - Martin H Entling
- Institute for Environmental Sciences, iES Landau, University of Koblenz-Landau, Fortstraße 7, D-76829, Landau, Germany
| | - Mirco Bundschuh
- Institute for Environmental Sciences, iES Landau, University of Koblenz-Landau, Fortstraße 7, D-76829, Landau, Germany; Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Lennart Hjelms väg 9, SWE-75007, Uppsala, Sweden
| | - Carsten A Brühl
- Institute for Environmental Sciences, iES Landau, University of Koblenz-Landau, Fortstraße 7, D-76829, Landau, Germany
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Poulin B, Lefebvre G, Hilaire S, Després L. Long-term persistence and recycling of Bacillus thuringiensis israelensis spores in wetlands sprayed for mosquito control. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2022; 243:114004. [PMID: 36007317 DOI: 10.1016/j.ecoenv.2022.114004] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 08/18/2022] [Accepted: 08/18/2022] [Indexed: 06/15/2023]
Abstract
Bacillus thuringiensis subsp. israelensis (Bti) is the main larvicide used to control mosquitoes worldwide. Although there is accumulating evidence of Bti having environmental effects on non-target fauna, relatively few field studies have documented the fate of Bti spores in the environment. Spore density was quantified over a 6-yr period (2012-2017) in Mediterranean marshes sprayed with Vectobac 12AS (32 ITU/ha) since 2006 to reduce the nuisance caused by Aedes caspius. Bti spores were naturally found in all habitat types. Spore density expressed as colony-forming units per gram of soil (CFU g-1) increased significantly at treated sites by a factor of 22 to 500 times relative to control sites, with mean values of 7730 CFU g-1 in halophilous scrubs, 38,000 in reed beds, 49,000 in bulrush beds and 50 000 in rush beds. Spore density varied little in the first months after the spraying season (April-October), but increased sharply in spring, just before the annual launch of mosquito control. Considering that Bti is an insect pathogen that cannot proliferate without a suitable insect host, this unexpected recrudescence in spring could be related to the warming of water that triggers activity and development of benthic organisms such as chironomids, which may contribute to Bti proliferation by ingesting accumulated spores at the surface of sediments. While spore density tends to decrease over time, presumably during the summer period as a result of increased UV exposure, three to four years were necessary for spore density to return to normal levels after mosquito-control interruption. This study is important because it demonstrates that environmental effects of mosquito-control using Bti can far exceed the short period of Bti efficacy against lentic mosquitoes. Considering that Bti is a microbial agent, these long-term effects should be addressed at multiple levels of ecosystem organization from a one-health perspective.
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Affiliation(s)
- Brigitte Poulin
- Tour duValat Research Institute for the Conservation of Mediterranean Wetlands, Le Sambuc, 13200 Arles, France.
| | - Gaëtan Lefebvre
- Tour duValat Research Institute for the Conservation of Mediterranean Wetlands, Le Sambuc, 13200 Arles, France.
| | - Samuel Hilaire
- Tour duValat Research Institute for the Conservation of Mediterranean Wetlands, Le Sambuc, 13200 Arles, France.
| | - Laurence Després
- Univ. Grenoble-Alpes, Univ. Savoie Mont Blanc, CNRS, Laboratoire d'Ecologie Alpine, 38000 Grenoble, France.
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6
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Bordalo MD, Machado AL, Campos D, Coelho SD, Rodrigues ACM, Lopes I, Pestana JLT. Responses of benthic macroinvertebrate communities to a Bti-based insecticide in artificial microcosm streams. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 282:117030. [PMID: 33831627 DOI: 10.1016/j.envpol.2021.117030] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 03/19/2021] [Accepted: 03/26/2021] [Indexed: 06/12/2023]
Abstract
Bioinsecticides based on the bacterium Bacillus thuringiensis subsp. israelensis (Bti) are increasingly being applied directly into aquatic compartments to control nuisance mosquitoes and blackflies and are generally considered environmentally friendly alternatives to synthetic insecticides. Bti-based insecticides are considered highly selective, being Diptera-specific, and supposedly decompose rapidly in the environment. Nevertheless, their safety to non-target species and freshwater ecosystems has been questioned by recent studies, which in fact document possible indirect effects in aquatic food webs such as the decrease of prey availability to predators. This work aimed to evaluate the potential effects of a Bti-based insecticide (VectoBac® 12AS) on a freshwater macroinvertebrate community and on stream ecological functions by using artificial microcosm streams. Artificial microcosm streams were colonized with a macroinvertebrate community plus periphyton collected in a stream together with Alnus glutinosa leaf packs. They were exposed for 7 days to different Bti treatments (0, 12, 120, 1200 μg/L), which are within the recommended concentrations of application in aquatic compartments for blackfly and mosquito control. Besides invertebrate community structure and abundance, effects were evaluated regarding leaf decomposition and primary production as measures of ecosystem functioning. Community structure was significantly altered in all Bti treatments after 7 days of exposure, mostly due to a decline in chironomids, followed by oligochaetes, which both belong to the deposit-feeders' functional group. Direct effects on oligochaetes are surprising and require further research. Also, reductions of leaf decomposition due to Bti-induced sublethal effects on shredders (reduced feeding) or mortality of chironomids (that can also feed on coarse organic matter) observed in our study, represent potential indirect effects of Bti in aquatic ecosystems. Our short-exposure experiment evidenced some negative effects on stream benthic invertebrate communities and on ecosystem functioning that must be considered whenever Bti is used in water bodies for blackfly or mosquito control programs.
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Affiliation(s)
- Maria D Bordalo
- CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Portugal.
| | - Ana L Machado
- CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Portugal
| | - Diana Campos
- CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Portugal
| | - Sónia D Coelho
- CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Portugal
| | - Andreia C M Rodrigues
- CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Portugal
| | - Isabel Lopes
- CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Portugal
| | - João L T Pestana
- CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Portugal
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Belousova ME, Malovichko YV, Shikov AE, Nizhnikov AA, Antonets KS. Dissecting the Environmental Consequences of Bacillus thuringiensis Application for Natural Ecosystems. Toxins (Basel) 2021; 13:toxins13050355. [PMID: 34065665 PMCID: PMC8155924 DOI: 10.3390/toxins13050355] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 05/10/2021] [Accepted: 05/13/2021] [Indexed: 12/30/2022] Open
Abstract
Bacillus thuringiensis (Bt), a natural pathogen of different invertebrates, primarily insects, is widely used as a biological control agent. While Bt-based preparations are claimed to be safe for non-target organisms due to the immense host specificity of the bacterium, the growing evidence witnesses the distant consequences of their application for natural communities. For instance, upon introduction to soil habitats, Bt strains can affect indigenous microorganisms, such as bacteria and fungi, and further establish complex relationships with local plants, ranging from a mostly beneficial demeanor, to pathogenesis-like plant colonization. By exerting a direct effect on target insects, Bt can indirectly affect other organisms in the food chain. Furthermore, they can also exert an off-target activity on various soil and terrestrial invertebrates, and the frequent acquisition of virulence factors unrelated to major insecticidal toxins can extend the Bt host range to vertebrates, including humans. Even in the absence of direct detrimental effects, the exposure to Bt treatment may affect non-target organisms by reducing prey base and its nutritional value, resulting in delayed alleviation of their viability. The immense phenotypic plasticity of Bt strains, coupled with the complexity of ecological relationships they can engage in, indicates that further assessment of future Bt-based pesticides' safety should consider multiple levels of ecosystem organization and extend to a wide variety of their inhabitants.
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Affiliation(s)
- Maria E. Belousova
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia; (M.E.B.); (Y.V.M.); (A.E.S.); (A.A.N.)
| | - Yury V. Malovichko
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia; (M.E.B.); (Y.V.M.); (A.E.S.); (A.A.N.)
- Faculty of Biology, St. Petersburg State University, 199034 St. Petersburg, Russia
| | - Anton E. Shikov
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia; (M.E.B.); (Y.V.M.); (A.E.S.); (A.A.N.)
- Faculty of Biology, St. Petersburg State University, 199034 St. Petersburg, Russia
| | - Anton A. Nizhnikov
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia; (M.E.B.); (Y.V.M.); (A.E.S.); (A.A.N.)
- Faculty of Biology, St. Petersburg State University, 199034 St. Petersburg, Russia
| | - Kirill S. Antonets
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia; (M.E.B.); (Y.V.M.); (A.E.S.); (A.A.N.)
- Faculty of Biology, St. Petersburg State University, 199034 St. Petersburg, Russia
- Correspondence:
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Holcomb KM, Reiner RC, Barker CM. Spatio-temporal impacts of aerial adulticide applications on populations of West Nile virus vector mosquitoes. Parasit Vectors 2021; 14:120. [PMID: 33627165 PMCID: PMC7905633 DOI: 10.1186/s13071-021-04616-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 01/29/2021] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Aerial applications of insecticides that target adult mosquitoes are widely used to reduce transmission of West Nile virus to humans during periods of epidemic risk. However, estimates of the reduction in abundance following these treatments typically focus on single events, rely on pre-defined, untreated control sites and can vary widely due to stochastic variation in population dynamics and trapping success unrelated to the treatment. METHODS To overcome these limitations, we developed generalized additive models fitted to mosquito surveillance data collected from CO2-baited traps in Sacramento and Yolo counties, California from 2006 to 2017. The models accounted for the expected spatial and temporal trends in the abundance of adult female Culex (Cx.) tarsalis and Cx. pipiens in the absence of aerial spraying. Estimates for the magnitude of deviation from baseline abundance following aerial spray events were obtained from the models. RESULTS At 1-week post-treatment with full spatial coverage of the trapping area by pyrethroid or pyrethrin products, Cx. pipiens abundance was reduced by a mean of 52.4% (95% confidence intrval [CI] - 65.6, - 36.5%) while the use of at least one organophosphate pesticide resulted in a mean reduction of 76.2% (95% CI - 82.8, - 67.9%). For Cx. tarsalis, at 1-week post-treatment with full coverage there was a reduction in abundance of 30.7% (95% CI - 54.5, 2.5%). Pesticide class was not a significant factor contributing to the reduction. In comparison, repetition of spraying over three to four consecutive weeks resulted in similar estimates for Cx. pipiens and estimates of somewhat smaller magnitude for Cx. tarsalis. CONCLUSIONS Aerial adulticides are effective for achieving a rapid short-term reduction of the abundance of the primary West Nile virus vectors, Cx. tarsalis and Cx. pipiens. A larger magnitude of reduction was estimated in Cx. pipiens, possibly due to the species' focal distribution. Effects of aerial sprays on Cx. tarsalis populations are likely modulated by the species' large dispersal ability, population sizes and vast productive larval habitat present in the study area. Our modeling approach provides a new way to estimate effects of public health pesticides on vector populations using routinely collected observational data and accounting for spatio-temporal trends and contextual factors like weather and habitat. This approach does not require pre-selected control sites and expands upon past studies that have focused on the effects of individual aerial treatment events.
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Affiliation(s)
- Karen M Holcomb
- Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, CA, 95616, USA
| | - Robert C Reiner
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, 98121, USA
| | - Christopher M Barker
- Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, CA, 95616, USA.
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9
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Reuss F, Kreß A, Braun M, Magdeburg A, Pfenninger M, Müller R, Mehring M. Knowledge on exotic mosquitoes in Germany, and public acceptance and effectiveness of Bti and two self-prepared insecticides against Aedes japonicus japonicus. Sci Rep 2020; 10:18901. [PMID: 33144626 PMCID: PMC7641113 DOI: 10.1038/s41598-020-75780-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 10/08/2020] [Indexed: 12/05/2022] Open
Abstract
Mosquito-borne diseases are a continuous challenge to public health. To prevent transmission, Integrated Vector Management (IVM) applies preventive, control, and communicational strategies that should be feasible, environmentally benign, and sustainable. IVM shows higher efficiency when being supported by local communities. Accordingly, we applied a social-ecological approach to identify the public acceptance of control measures and effectiveness of Eurocent coins containing copper, clove essential oil (EO) and Bacillus thuringiensis israelensis (Bti). We performed field and laboratory experiments to demonstrate the toxicity of alternative substances against Aedes japonicus japonicus. In expert interviews, we asked for (1) knowledge on exotic mosquitoes in Germany, (2) potential chances of alternative substances in future mosquito control, and (3) their needs for further clarification before application. We assessed potential users' (4) awareness of exotic mosquitoes and (5) willingness to apply the substances. Self-prepared copper coins and EO were clearly preferred by potential users over Bti. However, 100% mortality of the sensitive first stage could not be reached with the number of ten 5-Eurocent coins showing limited toxicity. Clove EO was shown to work as oviposition deterrent and larvicide with a LC50 of 17 mg l-1 (95% CI: 15-19 mg l-1). This study shows the importance of potential users' perspectives in IVM and the need for authorised insecticides.
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Affiliation(s)
- Friederike Reuss
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Georg-Voigt-Straße 14-16, 60325, Frankfurt am Main, Germany.
| | - Aljoscha Kreß
- Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Markus Braun
- Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Axel Magdeburg
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Georg-Voigt-Straße 14-16, 60325, Frankfurt am Main, Germany
- Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Markus Pfenninger
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Georg-Voigt-Straße 14-16, 60325, Frankfurt am Main, Germany
- LOEWE TBG (Translational Biodiversity Genomics), Senckenberganlage 25, 60325, Frankfurt am Main, Germany
- Institute of Organismic and Molecular Evolution (iOME), Johannes Gutenberg University, Gresemundweg 2, 55128, Mainz, Germany
| | - Ruth Müller
- Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
- Institute of Tropical Medicine, Nationalestraat 155, 2000, Antwerp, Belgium
| | - Marion Mehring
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Georg-Voigt-Straße 14-16, 60325, Frankfurt am Main, Germany
- ISOE - Institute for Social-Ecological Research, Biodiversity and People, Hamburger Allee 45, 60486, Frankfurt am Main, Germany
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10
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Brühl CA, Després L, Frör O, Patil CD, Poulin B, Tetreau G, Allgeier S. Environmental and socioeconomic effects of mosquito control in Europe using the biocide Bacillus thuringiensis subsp. israelensis (Bti). THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 724:137800. [PMID: 32249002 DOI: 10.1016/j.scitotenv.2020.137800] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 03/06/2020] [Accepted: 03/06/2020] [Indexed: 06/11/2023]
Abstract
Bacillus thuringiensis subsp. israelensis (Bti) has been used in mosquito control programs to reduce nuisance in Europe for decades and is generally considered an environmentally-safe, effective and target-specific biocide. However, the use of Bti is not uncontroversial. Target mosquitoes and affected midges represent an important food source for many aquatic and terrestrial predators and reduction of their populations is likely to result in food-web effects at higher trophic levels. In the context of global biodiversity loss, this appears particularly critical since treated wetlands are often representing conservation areas. In this review, we address the current large-scale use of Bti for mosquito nuisance control in Europe, provide a description of its regulation followed by an overview of the available evidence on the parameters that are essential to evaluate Bti use in mosquito control. Bti accumulation and toxin persistence could result in a chronic expose of mosquito populations ultimately affecting their susceptibility, although observed increase in resistance to Bti in mosquito populations is low due to the four toxins involved. A careful independent monitoring of mosquito susceptibility, using sensitive bioassays, is mandatory to detect resistance development timely. Direct Bti effects were documented for non-target chironomids and other invertebrate groups and are discussed for amphibians. Field studies revealed contrasting results on possible impacts on chironomid abundances. Indirect, food-web effects were rarely studied in the environment. Depending on study design and duration, Bti effects on higher trophic levels were demonstrated or not. Further long-term field studies are needed, especially with observations of bird declines in Bti-treated wetland areas. Socio-economic relevance of mosquito control requires considering nuisance, vector-borne diseases and environmental effects jointly. Existing studies indicate that a majority of the population is concerned regarding potential environmental effects of Bti mosquito control and that they are willing to pay for alternative, more environment-friendly techniques.
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Affiliation(s)
- Carsten A Brühl
- iES Landau, Institute for Environmental Sciences, University of Koblenz-Landau, D-76829 Landau, Germany.
| | - Laurence Després
- Université Grenoble Alpes, CNRS, Laboratoire d'Ecologie Alpine, F-38000 Grenoble, France
| | - Oliver Frör
- iES Landau, Institute for Environmental Sciences, University of Koblenz-Landau, D-76829 Landau, Germany
| | - Chandrashekhar D Patil
- Centre of Island Research and Environmental Observatory, PSL Université Paris: EPHE-UPVD-CNRS, USR 3278 CRIOBE, Université de Perpignan, F-66860 Perpignan, France
| | - Brigitte Poulin
- Tour du Valat, Research Institute for the Conservation of Mediterranean Wetlands, Le Sambuc, F-13200 Arles, France
| | | | - Stefanie Allgeier
- iES Landau, Institute for Environmental Sciences, University of Koblenz-Landau, D-76829 Landau, Germany
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11
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Allgeier S, Friedrich A, Brühl CA. Mosquito control based on Bacillus thuringiensis israelensis (Bti) interrupts artificial wetland food chains. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 686:1173-1184. [PMID: 31412513 DOI: 10.1016/j.scitotenv.2019.05.358] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 05/23/2019] [Accepted: 05/23/2019] [Indexed: 06/10/2023]
Abstract
The biocide Bacillus thuringiensis israelensis (Bti) has become the most commonly used larvicide to control mosquitoes in seasonal wetlands. Although Bti is considered non-toxic to most aquatic organisms, the non-biting chironomids show high susceptibilities towards Bti. As chironomids are a key element in wetland food webs, major declines in their abundance could lead to indirect effects that may be passed through aquatic and terrestrial food chains. We conducted two mesocosm experiments to address this hypothesis by assessing direct and indirect effects of Bti-modified availability of macroinvertebrate and zooplankton food resources on the predatory larvae of palmate and smooth newts (Urodelans: Lissotriton helveticus, Lissotriton vulgaris). We examined newt survival rates and dietary composition by means of stable isotope (δ15N and δ13C) analysis in the presence of Bti treatment and a predator (Odonata: Aeshna cyanea). We assessed palmate newts' body size at and time to metamorphosis while developing in Bti treated mesocosms. Chironomid larvae were the most severely affected aquatic invertebrates in all Bti treated food chains and experienced abundance reductions by 50 to 87%. Moreover, stable isotope analysis revealed that chironomids were preferred over other invertebrates and comprised the major part in newts' diet (56%) regardless of their availability. The dragonfly A. cyanea decreased survival of newt larvae by 27% in Bti treated mesocosms showing affected chironomid abundances. Increasing intraguild predation is most likely favored by the Bti-induced reduction of alternative prey such as chironomid larvae. The decreased food availability after Bti treatment led to slightly smaller L. helveticus metamorphs while their developmental time was not affected. Our findings highlight the crucial role of chironomids in the food webs of freshwater ecosystems. We are also emphasizing the importance of reconsidering human-induced indirect effects of mosquito control on valuable wetland ecosystems particularly in the context of worldwide amphibian and insect declines.
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Affiliation(s)
- Stefanie Allgeier
- iES Landau, Institute for Environmental Sciences, University of Koblenz-Landau, Fortstraße 7, 76829 Landau, Germany.
| | - Anna Friedrich
- iES Landau, Institute for Environmental Sciences, University of Koblenz-Landau, Fortstraße 7, 76829 Landau, Germany
| | - Carsten A Brühl
- iES Landau, Institute for Environmental Sciences, University of Koblenz-Landau, Fortstraße 7, 76829 Landau, Germany
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12
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Theissinger K, Röder N, Allgeier S, Beermann AJ, Brühl CA, Friedrich A, Michiels S, Schwenk K. Mosquito control actions affect chironomid diversity in temporary wetlands of the Upper Rhine Valley. Mol Ecol 2019; 28:4300-4316. [DOI: 10.1111/mec.15214] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 07/11/2019] [Accepted: 07/22/2019] [Indexed: 11/28/2022]
Affiliation(s)
- Kathrin Theissinger
- Institute for Environmental Sciences University of Koblenz‐Landau Landau Germany
| | - Nina Röder
- Institute for Environmental Sciences University of Koblenz‐Landau Landau Germany
| | - Stefanie Allgeier
- Institute for Environmental Sciences University of Koblenz‐Landau Landau Germany
| | - Arne J. Beermann
- Faculty of Biology Aquatic Ecosystem Research University of Duisburg‐Essen Essen Germany
| | - Carsten A. Brühl
- Institute for Environmental Sciences University of Koblenz‐Landau Landau Germany
| | - Anna Friedrich
- Institute for Environmental Sciences University of Koblenz‐Landau Landau Germany
| | | | - Klaus Schwenk
- Institute for Environmental Sciences University of Koblenz‐Landau Landau Germany
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