Irradiated males of the mosquito Aedes aegypti as disseminators of the entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae under laboratory conditions

Abstract

The mosquito Aedes aegypti (L.) (Diptera: Culicidae) is a vector of diseases of global importance, such as dengue fever, chikungunya, and Zika. The increasing geographic expansion of this species, as well as its resistance to chemical insecticides, has prompted the search for alternatives to reduce its populations. The sterile insect technique (SIT) is a promising technique that is applied to regulate mosquito vector populations through the release of sterile males. The use of entomopathogens is another promising technique for vector control. In this study, we evaluated the capacity of irradiated Ae. aegypti males to transport spores of the entomopathogenic fungi Beauveria bassiana (Bals.-Criv.) Vuill. (Ascomycota) and Metarhizium anisopliae (Metchn.) Sorokin (Ascomycota) and infect conspecific females. Our results show that irradiated Ae. aegypti males are able to transport and transmit an infection of both entomopathogens to conspecific females. The time to locate a female is more variable for irradiated males, but overall similar to that for nonirradiated males, and independent of fungal infection status. Thus, irradiation does not appear to affect the capacity of males to transmit a fungal infection to conspecific females. A combination of both control strategies, entomopathogens and SIT, is promising for the control of disease-carrying mosquitoes, but future studies of male sexual competitiveness, in the field in addition to the laboratory, are still required.