Toxicity of Bacillus thuringiensis var. israelensis in aqueous suspension on the South American common frog Leptodactylus latrans (Anura: Leptodactylidae) tadpoles

Junges, Celina María; Cabagna-Zenklusen, Mariana C.; Attademo, Andrés M.; Peltzer, Paola M.; Maglianese, Mariana; Márquez, Vanina Elizabet; Beccaria, Alejandro José

doi:10.1016/j.envres.2014.10.022

Cited by 42 publications

(27 citation statements)

References 46 publications

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“…Solid arrows represent positive coefficients, and dashed arrows negative coefficients. However, in a recent study, Lajmanovich et al (2015) demonstrated negative effects of Bti on glutathione S-transferase activities, and histological anomalies of intestines of tadpoles of the South American common frog (Leptodactylus latrans), but at a very high dosage (between 4-to 80-fold the recommended application rate). abundance was of short duration and immediate after the treatment at high dosage.…”

Section: Discussionmentioning

confidence: 99%

“…Laboratory tests and field studies have shown that Bti may be safe to the environment due to its selectivity (Mulla et al 1982, Barnes and Chapman 1998, Boisvert and Lacoursi ere 2004, Duchet et al 2010b. However, in a recent study, Lajmanovich et al (2015) demonstrated negative effects of Bti on glutathione S-transferase activities, and histological anomalies of intestines of tadpoles of the South American common frog (Leptodactylus latrans), but at a very high dosage (between 4-to 80-fold the recommended application rate). Most wetlands studies, including long-term monitoring (6 yr or more), did not show any significant effects of Bti on aquatic invertebrate communities (Vijverberg 1980, Russell et al 2009, Vinnersten et al 2009, Caquet et al 2011, Lagadic et al 2014, 2016, although results of in situ studies on non-target organisms remain controversial (Hershey et al 1995, Liber et al 1998, Niemi et al 1999, Poulin et al 2010.…”

Section: ) Ecological Traps Have Been Observed Withmentioning

confidence: 96%

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Pesticide‐mediated trophic cascade and an ecological trap for mosquitoes

et al. 2018

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Broad-spectrum pesticides can have immediate toxic effects both on target pest species and on non-target species. They may also have positive residual effects on mosquitoes after pesticide degradation, by altering the community structure, that is, by reducing abundances of mosquito competitors and predators, and via a trophic cascade, which may increase food resources for mosquito larvae. Alternatively, if a pesticidemediated trophic cascade results in toxic or inedible algae, the pesticide can act as an ecological trap for some taxa by attracting oviposition in sites where algae are abundant but unsuitable. The present study assessed mosquito oviposition habitat selection, mosquito larval performance, and community structure alterations after applications of various pesticides. The experiment was conducted in outdoor mesocosms assigned to one of four treatments: (1) control, no pesticides; (2) Bacillus thuringiensis var. israelensis (Bti), a narrow-spectrum bacterium well known for its larvicidal activity on mosquitoes and other dipterans; (3) temephos, an organophosphate mosquito larvicide with community-wide spectrum effects; and (4) pyriproxyfen, a pyridine-based insect growth regulator (IGR) class with wide-spectrum effects. Soon after pesticide application, Culex pipiens oviposition was highest in the control pools. Invertebrate species richness and abundance were strongly reduced in the broad-spectrum pesticide treatments (temephos and pyriproxyfen) when compared to control. One month after pesticide application, Cx. pipiens oviposition was highest in the pyriproxyfen-treated pools, although larval survival remained lowest in the pyriproxyfen-treated pools. Our results suggest that pyriproxyfen causes a chemically mediated trophic cascade and provides an ecological trap, that is, attracting mosquito oviposition due to an altered community structure, but causing high mosquito larval mortality.

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Section: Discussionmentioning

confidence: 99%

Section: ) Ecological Traps Have Been Observed Withmentioning

confidence: 96%

Pesticide‐mediated trophic cascade and an ecological trap for mosquitoes

et al. 2018

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“…Furthermore, the increasing use of microbial insecticides has raised concerns regarding their ability to disseminate, survive and multiply in other environments where there is a risk of infection of non‐target species . In fact, deleterious effects of microbial insecticides on non‐target species have been reported and further ecotoxicological assays evaluating their potential impact on freshwater non‐target insects are needed. This evaluation should rely on not only acute toxicity tests, but also sublethal effects including sub‐organismal and immunological responses that can be altered by different natural and chemical insecticidal compounds .…”

Section: Introductionmentioning

confidence: 99%

Toxicity of microbial insecticides toward the non‐target freshwater insect Chironomus xanthus

Dornelas

Sarmento

Silva

et al. 2019

Pest Management Science

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BACKGROUND Commercial formulations based on Bacillus thuringiensis subs. kurstaki (Btk) and Beauveria bassiana (Bb) are commonly used microbial insecticides in Brazil and other tropical regions. However, and despite being considered environmentally friendly, their use generates concerns regarding possible adverse ecological effects in freshwater ecosystems. Here, we evaluate the effects of these bioinsecticides on the tropical aquatic dipteran Chironomus xanthus under laboratory conditions. RESULTS After laboratory exposures to these compounds 48‐h median lethal concentration (LC50) values of 1534 μg a.i./L for Btk and of 6.35 μg a.i./L for Bb were estimated. Chronic assays revealed different sublethal effects: Btk‐based bioinsecticide exposure reduced C. xanthus growth [lowest observed effect concentration (LOEC) was 126 μg a.i./L for head width], decreased emergence rate (LOEC = 8 μg a.i./L) and increased immunological response (LOEC = 50 μg a.i./L) measured as total hemocyte count in larvae hemolymph. Exposure to low concentrations of Bb‐based insecticide also reduced C. xanthus growth (LOEC = 0.07 μg a.i./L for larvae body length measurements), and emergence rate (LOEC = 0.28 μg a.i./L), despite no clear effects on the total hemocyte counts. CONCLUSION Our results suggest that low concentrations of Btk and Bb bioinsecticides are toxic to C. xanthus. Given their widespread use and occurrence in tropical freshwater systems, research is needed to evaluate the potential effects of these compounds concerning natural freshwater insect communities and ecosystem functioning. © 2019 Society of Chemical Industry

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“…In particular, nonbiting midges (Chironomidae) may be susceptible to Bti [8][9][10], albeit at doses more than ten times greater than those recommended for mosquito control [11]. Nevertheless, some evidence for direct impacts of Bti on NTOs exists [12,13], including on vertebrate species [14].…”

Section: Introductionmentioning

confidence: 99%

What are the effects of control of mosquitoes and other nematoceran Diptera using the microbial agent Bacillus thuringiensis israelensis (Bti) on aquatic and terrestrial ecosystems? A systematic review protocol

et al. 2019

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Background: The bacterium Bacillus thuringiensis serovar israelensis (Bti) is used in many countries as a biological larvicide to control dipteran insects of the suborder Nematocera, especially mosquitoes and black flies. Bti is generally accepted to be target-specific and efficient, with low potential for development of resistance among the target species. However, even though Bti may have minimal direct effects on non-target organisms, it might potentially be associated with knock-on effects on food webs and other ecosystem properties, including biodiversity and ecosystem functioning. Evidence from previous research is mixed, with some finding no evidence for indirect effects on biodiversity and ecosystem-level properties, but others indicating that such effects are possible. The fact that many studies have been conducted by organisations coordinating the control programs, and that many of those studies have been published outside peer reviewed scientific journals, highlights the challenges for decision makers and others to assess the results of the existing studies. In this protocol we outline how we aim to systematically and transparently synthesise all available evidence in a forthcoming systematic review. Methods: We will use six bibliographic databases/platforms and the online search engines Google and Google Scholar in searches for literature. Searches will also be made on specialist websites. We will screen the search results for eligibility in stage one based on title and abstract, and in stage two based on the full text of the material. At stage one, after testing and clarifying the eligibility criteria, two reviewers will split and single screen the search results. At stage two the articles will be screened independently by two reviewers. We have developed a preliminary critical appraisal tool that will be used as basis for assessing study validity. Each study will be critically appraised independently by two reviewers. Disagreements will be reconciled through discussions seeking to reach consensus. It is unclear whether a quantitative synthesis based on meta-analysis will be feasible. A narrative synthesis will include descriptive statistics outlining the evidence base in terms of bibliographic information and study metadata. A narrative synthesis table in the form of an Excel spreadsheet will be provided.

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Toxicity of Bacillus thuringiensis var. israelensis in aqueous suspension on the South American common frog Leptodactylus latrans (Anura: Leptodactylidae) tadpoles

Cited by 42 publications

References 46 publications

Pesticide‐mediated trophic cascade and an ecological trap for mosquitoes

Pesticide‐mediated trophic cascade and an ecological trap for mosquitoes

Toxicity of microbial insecticides toward the non‐target freshwater insect Chironomus xanthus

What are the effects of control of mosquitoes and other nematoceran Diptera using the microbial agent Bacillus thuringiensis israelensis (Bti) on aquatic and terrestrial ecosystems? A systematic review protocol

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