Corrigendum: Does mosquito control by Bti spraying affect the phytoplankton community? A 5-year study in Camargue temporary wetlands (France)

Abstract

This article is a corrigendum of a former version by Fayolle et al., originally published in Ann. Limnol. -Int. J. Lim. 51: 189-198, 2015. In its original form, the article contained portions of text that were identical to Duguma et al., J. Appl. Ecol. 52: 763-773, 2015, similarities that were not detected by our plagiarism detection software upon initial submission of Fayolle et al.'s manuscript. Based on independent investigations, the Editors of Ann. Limnol. Where Ann. Limnol. -Int. J. Lim. is concerned, plagiarism check remains a common practice at the time of first submission, but we will now systematically check revised manuscripts as well. Last, we wish to thank the authors of both articles as well as the Editor of J. Appl. Ecol. for helping us sorting out a very difficult situation. The EditorsAbstract -Mosquitoes are both vectors of disease and a hindrance to outdoor activities. Since its discovery in 1976, the larvicide Bacillus thuringiensis var. israelensis (Bti) has proven its effectiveness in controlling mosquito populations, with negligible environmental impact. We performed an integrated, 5-year study of the direct and indirect effects of Bacillus thuringiensis var. israelensis (Bti applied as VectoBac 1 WG) on phytoplankton communities in the Camargue temporary wetlands of the French Mediterranean coast. Mosquito larvae are considered major algae predators, so a significant reduction in mosquito larval density ( > 80%) in natural wetlands due to Bti treatment could indirectly affect phytoplankton communities. Physical parameters and phytoplankton were sampled in the water of three temporary oligohaline pools between 2006 and 2011 in the following order: T0 = 1 day before treatment (control), T2 = 2 days after treatment, T5 = 5 days after treatment, T11 = 11 days after treatment. We found no negative effects of Bti treatments on total phytoplankton density and community diversity (Shannon's entropy and Pielou's evenness). However, we observed changes in the density of some taxonomic groups; Diatoms were replaced by drought-resistant algae typical of temporary wetlands. These results suggest that changes in phytoplankton community structure are largely driven by natural environmental factors and by the ecological complexity of these temporary wetlands.

No association between the use of Bti for mosquito control and the dynamics of non-target aquatic invertebrates in French coastal and continental wetlands

“…Bean plot representation of the Bray-Curtis dissimilarity between control and VectoBac®-treated areas for non-target invertebrate (A) and chironomid (B) communities within the study period in all sites. Overall, these results support the absence of relevant effects of Bti on aquatic food webs, as already evidenced by a number of field studies in wetlands (Painter et al, 1996;Blum et al, 1997;Balcer et al, 1999;Niemi et al, 1999;Lagadic et al, 2014;Fayolle et al, 2015).…”

“…More importantly, Duguma et al (2015) demonstrated that the reduced grazing pressure resulting from the reduction of mosquito larvae populations did not enhance microalgal biomass. This supports the absence of a top-down regulation of microorganism communities by mosquito larvae (Su and Mulla, 1999a;Fayolle et al, 2015).…”

Interactions between Bt crops and aquatic ecosystems: A review

“…They reported reduced clutch size and fledgling survival of house martins ( Delichon urbicum ), which they explained as an indirect effect of the use of Bti spray, correlating the use of the spray with decreased availability of certain house martin prey (Nematocera and the spiders and dragonflies that feed on them). This study was criticized for having its reference sites too far from its study sites, and a later study by Lagadic et al in a different area of France did not find any effects as a result of the application of Bt sprays, in agreement with a number of other studies .…”

A participatory approach for malaria control in southern Malawi : Effects of the environment and community on larval source management

“…israelensis (Bti) and Bacillus sphaericus (Bs), are effective larvicides against mosquitoes (Walker and Lynch 2007). The use of Bti has demonstrated no harm to non-target organisms, which can be attributed to the specificity of its endotoxins (Gwal et al 2015), as well as no harm to the environment due to its low persistence under field conditions (Davis and Peterson 2008, Tetreau et al 2012, Fayolle et al 2016).…”

“…In mosquitoes, the protein crystals bind to specific receptors exposed on the surface of the plasma membrane and then insert into the membrane, creating lytic pores in microvilli of apical membranes (Aronson and Shai 2001) that disturb the cell's osmotic balance, resulting in cell lysis and consequently death of the larvae (De Maagd et al 2001, Bravo et al 2007. The low persistence of Bti toxins under field conditions (Tetreau et al 2012) makes Bti an ecofriendly larvicide even when used in repeated treatments from three to seven years (Fayolle et al 2016). This rapid degradation, however, necessitates repeated applications of the larvicide for effective control of target organisms.…”