Sexual Competitiveness and Induced Egg Sterility by Aedes aegypti and Aedes albopictus Gamma-Irradiated Males: A Laboratory and Field Study in Mexico

• Published in: Insects (Basel, Switzerland) Switzerland), 2021-02, Vol.12 (2), p.145
• Main Authors: Bond, J Guillermo, Aguirre-Ibáñez, Santiago, Osorio, Adriana R, Marina, Carlos F, Gómez-Simuta, Yeudiel, Tamayo-Escobar, Rodolfo, Dor, Ariane, Liedo, Pablo, Carvalho, Danilo O, Williams, Trevor
• Format: Article
• Language: English
• Subjects: Aedes aegypti; Aedes albopictus; arboviruses; Cages; Competitiveness; Dosimetry; egg production; egg viability; Eggs; Females; Fertility; Gonotrophic cycles; Hatching; Health risks; Humidity; Insects; Irradiation; Laboratories; Males; Mating; Medical importance; mosquito vector; Mosquitoes; Pest control; Public health; Radiation; Radiation dosage; SIT; Species; sterile insect technique; Sterility; Sterilized organisms; Vectors; Zika virus
• ISSN: 2075-4450; 2075-4450
• DOI: 10.3390/insects12020145

The sterile insect technique may prove useful for the suppression of mosquito vectors of medical importance in regions where arboviruses pose a serious public health threat. In the present study, we examined the effects of sterilizing irradiation doses across different ratios of fertile:irradiated males on the mating competitiveness of and under laboratory and field-cage conditions. For both species, the percentage of females inseminated and the number of eggs laid over two gonotrophic cycles varied significantly in mating treatments involving 1:1, 1:5, and 1:10 fertile:irradiated males compared to controls of entirely fertile or entirely irradiated males but was not generally affected by the irradiation dose. Egg hatching was negatively affected in females exposed to increasing proportions of irradiated males in both laboratory and field cages. Male competitiveness (Fried's index) values varied from 0.19 to 0.58 in the laboratory and were between 0.09 and 1.0 in field cages, depending on th species. Competitiveness values were negatively affected by th eirradiation dose in both species under field-cage conditions, whereas in the laboratory, was sensitive to the dose but was not. In general, male competitiveness was similar across all mating regimes. Most importantly, induced egg sterility was positively correlated with the proportion of irradiated males present in the mating treatments, reaching a maximum of 88% under field-cage conditions for both and males treated with 50 and 40 Gy irradiation, respectively. These results indicate that sterile males produced at our facility are suitable and competitive enough for field pilot SIT projects and provide guidance to decide the optimal sterile:fertile ratios.