INBIOTEC   24408
INSTITUTO DE INVESTIGACIONES EN BIODIVERSIDAD Y BIOTECNOLOGIA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Microalga as a potential agent for the mosquito biocontrol.
Autor/es:
BATTAGLIA M; GIL MF; BERÓN CM; FASSOLARI M
Lugar:
Buenos Aires
Reunión:
Congreso; XV CONGRESO ARGENTINO DE MICROBIOLOGÍA GENERAL SAMIGE; 2020
Institución organizadora:
SAMIGE-SAIB
Resumen:
The mosquito Culex quinquefasciatus is able to vectorize pathogens of medical importance causing diseases such as filariasis, West Nile virus and different encephalitis in Asia, Africa, Central and South America. Currently, the biological control of this vector populations is carried out using entomopathogenic bacteria based on formulations; however, microorganisms from other taxa are also potential tools to be included in integrated management programs of these insects. Although microalgae are a major component in the diet of mosquito larvae, some species kill larvae primarily because they are indigestible or produce toxic compounds, being potential biological agents for larvicidal control. During entomological surveillance samplings of mosquitoes of sanitary importance carried out in artificial breeding sites along Provincial Route N° 2, Buenos Aires, Argentina, we found a microalga with potential mosquitocidal effect. For that, the aim of this work was to identify this microorganism and explore its toxic activity against two Culex quinquefasciatus isolines, one of them naturally infected with the endosymbiont bacterium Wolbachia spp. (w+) and the other Wolbachia-free (w-). Additionally, its effect on female choice for oviposition-substratum was examined. The microalga was identified by molecular methods as a belonging to the genus Neochloris spp. In order to analyze the nutritional value or insecticidal activity, a survival test was carried out using second-stage larvae of each isoline feeding with a microalga suspension, fish food as control diet or microalga suspension + control diet. Larvae survival was monitored and measurements of total length, thorax and fat body width were taken at different times of development; in addition, percentage of adult emergence was determined. When larvae were fed only with the microalga suspension, a lack of development was observed, while larvae fed with algae + control diet were able to reach adult stage, taking more time to reach their complete development in contrast with the control treatment. To analyze the impact of the alga on the oviposition site preferences, thirty Cx. quinquefasciatus gravid females of each isoline were individualized in rearing cages with two oviposition containers, one containing dechlorinated water and the other the microalga suspension. The site of preference for oviposition was recorded and the data were analyzed by the Binomial test. The results obtained showed a marked preference for the microalga suspension in the isoline w+; however, no significant differences were observed on the w- line. To conclude, although the larval development was interrupted when alga was the only source of food, the Cx. quinquefasciatus gravid females chose Neochloris spp. suspension as oviposition site. So, the effect of Neochloris spp. on mosquito larvae will require further studies.