title: No association between the use of Bti for mosquito control and the dynamics of non-target aquatic invertebrates in French coastal and continental wetlands.
abstract: The environmental safety of Bacillus thuringiensis subsp. israelensis (Bti) is still controversial, mainly because most of the previous field studies on its undesired effects were spatially limited and did not address the relationship between community similarity and application time and frequency. No general statement can therefore be drawn on the usage conditions of Bti that insure protection of non-target organisms. The present study was conducted in eight sites distributed over the main geographical sectors where mosquito control is implemented in mainland France and Corsica. Changes in non-target aquatic invertebrates were followed at elapsed time after repeated applications of two Bti formulations (VectoBac® WDG or 12AS) up to four consecutive years. We examined the influence of both larvicide treatments and environmental variables on community dynamics and dissimilarity between treated and control areas. As it can be argued that chironomids are the most vulnerable group of non-target invertebrates, we scrutinised potential Bti-related effects on the dynamics of their community. The use of VectoBac® WDG and 12AS in coastal and continental wetlands had no immediate or long-term detectable effect on the taxonomic structure and taxa abundance of non-target aquatic invertebrate communities, including chironomids. This applied to the main habitats where mosquito larvae occur, regardless of their geographic location. Flooding, whose frequency and duration depend on local meteorological and hydrological conditions, was identified as the main environmental driver of invertebrate community dynamics. Our findings add support to the environmental safety of currently available Bti formulations when following recommended application rates and best mosquito control practices.
authors.affiliation: INRA, UMR985 Écologie et Santé des Écosystèmes, Agrocampus Ouest, 65 rue de Saint Brieuc, F-35042 Rennes, France. Electronic address: Laurent.Lagadic@rennes.inra.fr.
authors.forename: Laurent
authors.initials: L
authors.lastname: Lagadic
authors.affiliation: Quantitative Landscape Ecology, Institute for Environmental Sciences, University of Koblenz-Landau, Fortstraße 7, D-76829 Landau, Germany.
authors.forename: Ralf B
authors.initials: RB
authors.lastname: Schäfer
authors.affiliation: INRA, UMR985 Écologie et Santé des Écosystèmes, Agrocampus Ouest, 65 rue de Saint Brieuc, F-35042 Rennes, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Roucaute
authors.affiliation: Quantitative Landscape Ecology, Institute for Environmental Sciences, University of Koblenz-Landau, Fortstraße 7, D-76829 Landau, Germany.
authors.forename: Eduard
authors.initials: E
authors.lastname: Szöcs
authors.affiliation: Etablissement Interdépartemental pour la Démoustication du Littoral Atlantique, 1 rue Toufaire, F-17300 Rochefort-sur-Mer, France.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Chouin
authors.affiliation: Etablissement Interdépartemental pour la Démoustication du Littoral Atlantique, 1 rue Toufaire, F-17300 Rochefort-sur-Mer, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: de Maupeou
authors.affiliation: Entente Interdépartementale pour la Démoustication du Littoral Méditerranéen, 165 avenue Paul-Rimbaud, F-34184 Montpellier, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Duchet
authors.affiliation: Aix Marseille Université, Institut Méditerranéen de Biodiversité et d'Ecologie marine et continentale (IMBE), UMR CNRS IRD Avignon Université, Faculté de Sciences et Techniques de St-Jérôme, F-13397 Marseille, France.
authors.forename: Evelyne
authors.initials: E
authors.lastname: Franquet
authors.affiliation: Etablissement Interdépartemental pour la Démoustication du Littoral Atlantique, 1 rue Toufaire, F-17300 Rochefort-sur-Mer, France.
authors.forename: Benoit
authors.initials: B
authors.lastname: Le Hunsec
authors.affiliation: Aix Marseille Université, Institut Méditerranéen de Biodiversité et d'Ecologie marine et continentale (IMBE), UMR CNRS IRD Avignon Université, Faculté de Sciences et Techniques de St-Jérôme, F-13397 Marseille, France.
authors.forename: Céline
authors.initials: C
authors.lastname: Bertrand
authors.affiliation: Aix Marseille Université, Institut Méditerranéen de Biodiversité et d'Ecologie marine et continentale (IMBE), UMR CNRS IRD Avignon Université, Faculté de Sciences et Techniques de St-Jérôme, F-13397 Marseille, France.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Fayolle
authors.affiliation: Entente Interdépartementale pour la Démoustication du Littoral Méditerranéen, 165 avenue Paul-Rimbaud, F-34184 Montpellier, France.
authors.forename: Benoît
authors.initials: B
authors.lastname: Francés
authors.affiliation: Entente Interdépartementale Rhône-Alpes pour la Démoustication, 31 Chemin des Prés de la Tour, F-73310 Chindrieux, France.
authors.forename: Yves
authors.initials: Y
authors.lastname: Rozier
authors.affiliation: Entente Interdépartementale Rhône-Alpes pour la Démoustication, 31 Chemin des Prés de la Tour, F-73310 Chindrieux, France.
authors.forename: Rémi
authors.initials: R
authors.lastname: Foussadier
authors.affiliation: Conseil Départemental de Corse du Sud, Service de Lutte Antivectorielle, Hôtel du Département, Palais Lantivy, BP 414, F-20183 Ajaccio, France.
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Santoni
authors.affiliation: Entente Interdépartementale pour la Démoustication du Littoral Méditerranéen, 165 avenue Paul-Rimbaud, F-34184 Montpellier, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Lagneau
mesh_terms: D000818:Animals; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000633:toxicity*; D017753:Ecosystem; D004731:Endotoxins / Q000633:toxicity*; D004784:Environmental Monitoring; D005602:France; D006460:Hemolysin Proteins / Q000633:toxicity*; D007306:Insecticides / Q000633:toxicity*; D007448:Invertebrates / Q000502:physiology*; D009032:Mosquito Control / Q000379:methods*; D010572:Pest Control, Biological / Q000379:methods*; D053833:Wetlands
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; D007306:Insecticides; C030956:insecticidal crystal protein, Bacillus Thuringiensis
keywords: Aquatic non-target invertebrates; Bacillus thuringiensis israelensis; Biopesticide; Chironomids; Field biomonitoring; Mosquito control