The susceptibility larvae of Ae. aegypti, kept under controlled conditions, was assessed using plastic cups containing 10 mL of drinking distilled water, 1 mL of the total bacterial culture and 10 third-instar Ae. aegypti larvae. The negative control consisted of 10 larvae placed in a plastic cup with water, but without bacterial culture and the positive control with the standard B. thuringiensis var. israelensis (Bti) serotype H-14 (VectorBac®WG), following the same protocol previously described for B. thuringiensis isolates. All bioassays were performed in three replications. After 24 h and 48 h, the larval mortality was verified by counting living and dead larvae. The larvae that did not move when touched with a sterile stick were considered dead.
Author(s) Details:
Maria Cleoneide da Silva
Entomopathogenic Bacteria and Molecular Markers Laboratory, Maranhão State University (UEMA), Campus Caxias, Caxias, MA, Brazil.
Jeverson Renato Moraes Brito
Entomopathogenic Bacteria and Molecular Markers Laboratory, Maranhão State University (UEMA), Campus Caxias, Caxias, MA, Brazil.
Emanuelle Cristine Pereira de Sousa
Entomopathogenic Bacteria and Molecular Markers Laboratory, Maranhão State University (UEMA), Campus Caxias, Caxias, MA, Brazil.
Dalton Kaynnan de Prado Costa
Complex Genetics and Molecular Biology Laboratory, Maranhão State University (UEMA), Campus Caxias, Caxias, MA, Brazil.
Alessandra Maria Silva Vidigal
Complex Genetics and Molecular Biology Laboratory, Maranhão State University (UEMA), Campus Caxias, Caxias, MA, Brazil.
Recent Global Research Developments in Impact of Bacillus thuringiensis Bioinsecticides on Drosophila melanogaster Larval Development
Bacillus thuringiensis (Bt) and its products are commonly used to control insect pests. However, there have been concerns about their limited field stability. To address this, researchers have explored various techniques to develop new recombinant Bt toxins with broader insect spectra, improved environmental stability, and more efficient delivery to pest insects [1]
Effects on Non-Target Insects:
- Using concentrations achievable in the field, Bt-based products were found to impair the growth and developmental time of non-target insects like Drosophila melanogaster (fruit flies) through a synergy between Bt bacteria and insecticidal toxins [2].
- Scarce data are available on the unintended effects of Bt strains on non-target insects, but this study sheds light on the developmental defects caused by Bt strains targeting lepidopteran larvae [3].
Strategies for Enhanced Control:
- Researchers continue to develop hybrid/mutated Bt insecticidal toxins with improved activity and a broader spectrum of target insects. These toxins are crucial for controlling resistant insect pests and delaying resistance evolution [1].
- Additionally, exploring other genes encoding non-Bt proteins (such as protease inhibitors, lectins, cholesterol oxidases, and chitinases) from various sources may provide new tools for combating insect damage [1].
References
- Azizoglu, U., Salehi Jouzani, G., Sansinenea, E. et al. Biotechnological advances in Bacillus thuringiensis and its toxins: Recent updates. Rev Environ Sci Biotechnol 22, 319–348 (2023). https://doi.org/10.1007/s11157-023-09652-5
- Nawrot-Esposito M-P, Babin A, Pasco M, Poirié M, Gatti J-L, Gallet A. Bacillus thuringiensis Bioinsecticides Induce Developmental Defects in Non-Target Drosophila melanogaster Larvae. Insects. 2020; 11(10):697. https://doi.org/10.3390/insects11100697
- Nawrot-Esposito, M. P., Babin, A., Pasco, M., Poirié, M., Gatti, J. L., & Gallet, A. (2020). Bacillus thuringiensis bioinsecticides induce developmental defects in non-target Drosophila melanogaster larvae. Insects, 11(10), 697.