TY - JOUR
T1 - Dissemination of Metarhizium anisopliae of low and high virulence by mating behavior in Aedes aegypti
AU - Reyes-Villanueva, Filiberto
AU - Garza-Hernandez, Javier A.
AU - Garcia-Munguia, Alberto M.
AU - Tamez-Guerra, Patricia
AU - Howard, Annabel Fv
AU - Rodriguez-Perez, Mario A.
N1 - Funding Information:
This study was financially supported by Secretaría de Investigación y Posgrado-Instituto Politécnico Nacional (IPN)-Megaproyecto II Red Biotecnología. Filiberto Reyes-Villanueva holds a posdoctoral scholarship from Consejo Nacional de Ciencia y Tecnología-México. Mario A. Rodríguez-Pérez holds a scholarship from Comisión de Operación y Fomento de Actividades Académicas (COFAA)/IPN. We thank COFAA-IPN to cover the publication fees of the present research article. The strain of M. anisopliae Ma-CBG-2 of this study was deposited at the United States Department of Agriculture (USDA) with code NRRL 50458.
PY - 2011/9/14
Y1 - 2011/9/14
N2 - Abstract. Background: Dengue is a viral disease transmitted by Aedes mosquitoes. It is a threat for public health worldwide and its primary vector Aedes aegypti is becoming resistant to chemical insecticides. These factors have encouraged studies to evaluate entomopathogenic fungi against the vector. Here we evaluated mortality, infection, insemination and fecundity rates in A. aegypti females after infection by autodissemination with two Mexican strains of Metarhizium anisopliae. Methods. Two M. anisopliae strains were tested: The Ma-CBG-1 least virulent (lv), and the Ma-CBG-2 highly virulent (hv) strain. The lv was tested as non mosquito-passed (NMP), and mosquito-passed (MP), while the hv was examined only as MP version, therefore including the control four treatments were used. In the first bioassay virulence of fungal strains towards female mosquitoes was determined by indirect exposure for 48 hours to conidia-impregnated paper. In the second bioassay autodissemination of fungal conidia from fungus-contaminated males to females was evaluated. Daily mortality allowed computation of survival curves and calculation of the LT50by the Kaplan-Meier model. All combinations of fungal sporulation and mating insemination across the four treatments were analyzed by 2. The mean fecundity was analyzed by ANOVA and means contrasted with the Ryan test. Results: Indirect exposure to conidia allowed a faster rate of mortality, but exposure to a fungal-contaminated male was also an effective method of infecting female mosquitoes. All females confined with the hv strain-contaminated male died in fifteen days with a LT50of 7.57 ( 0.45) where the control was 24.82 ( 0.92). For the lv strain, it was possible to increase fungal virulence by passing the strain through mosquitoes. 85% of females exposed to hv-contaminated males became infected and of them just 10% were inseminated; control insemination was 46%. The hv strain reduced fecundity by up to 99%, and the lv strain caused a 40% reduction in fecundity. Conclusions: The hv isolate infringed a high mortality, allowed a low rate of insemination, and reduced fecundity to nearly zero in females confined with a fungus-contaminated male. This pathogenic impact exerted through sexual transmission makes the hv strain of M. anisopliae worthy of further research.
AB - Abstract. Background: Dengue is a viral disease transmitted by Aedes mosquitoes. It is a threat for public health worldwide and its primary vector Aedes aegypti is becoming resistant to chemical insecticides. These factors have encouraged studies to evaluate entomopathogenic fungi against the vector. Here we evaluated mortality, infection, insemination and fecundity rates in A. aegypti females after infection by autodissemination with two Mexican strains of Metarhizium anisopliae. Methods. Two M. anisopliae strains were tested: The Ma-CBG-1 least virulent (lv), and the Ma-CBG-2 highly virulent (hv) strain. The lv was tested as non mosquito-passed (NMP), and mosquito-passed (MP), while the hv was examined only as MP version, therefore including the control four treatments were used. In the first bioassay virulence of fungal strains towards female mosquitoes was determined by indirect exposure for 48 hours to conidia-impregnated paper. In the second bioassay autodissemination of fungal conidia from fungus-contaminated males to females was evaluated. Daily mortality allowed computation of survival curves and calculation of the LT50by the Kaplan-Meier model. All combinations of fungal sporulation and mating insemination across the four treatments were analyzed by 2. The mean fecundity was analyzed by ANOVA and means contrasted with the Ryan test. Results: Indirect exposure to conidia allowed a faster rate of mortality, but exposure to a fungal-contaminated male was also an effective method of infecting female mosquitoes. All females confined with the hv strain-contaminated male died in fifteen days with a LT50of 7.57 ( 0.45) where the control was 24.82 ( 0.92). For the lv strain, it was possible to increase fungal virulence by passing the strain through mosquitoes. 85% of females exposed to hv-contaminated males became infected and of them just 10% were inseminated; control insemination was 46%. The hv strain reduced fecundity by up to 99%, and the lv strain caused a 40% reduction in fecundity. Conclusions: The hv isolate infringed a high mortality, allowed a low rate of insemination, and reduced fecundity to nearly zero in females confined with a fungus-contaminated male. This pathogenic impact exerted through sexual transmission makes the hv strain of M. anisopliae worthy of further research.
KW - Aedes aegypti
KW - autodissemination
KW - mating behavior
KW - Metarhizium anisopliae
KW - sexual transmission
KW - vector
KW - virulence
UR - http://www.scopus.com/inward/record.url?scp=80052597613&partnerID=8YFLogxK
U2 - 10.1186/1756-3305-4-171
DO - 10.1186/1756-3305-4-171
M3 - Artículo
C2 - 21906283
AN - SCOPUS:80052597613
SN - 1756-3305
VL - 4
JO - Parasites and Vectors
JF - Parasites and Vectors
IS - 1
M1 - 171
ER -