Field Performance Assessment of Irradiated Aedes albopictus Males Through Mark-Release-Recapture Trials With Multiple Release Points

Mark-release-recapture (MRR) trials have been conducted in Northern Italy to evaluate the capacity of radio-substerilized Aedes albopictus males to survive, disperse, and engage in mating in the field. Two MRR sessions with the human landing collection method (HLC) were conducted with the simultaneous release of irradiated males marked with four different pigment colors. The survival and dispersal rates seem to be influenced more by environmental factors such as barriers, shading, and vegetation rather than weather parameters. In this study, we confirmed a positive linear relationship between the sterile adult male's daily survival rate and the relative humidity previously reported in similar experimental conditions and a different dispersal capacity of the released A. albopictus males in low- (NDVI index <0.4) and high (NDVI index >0.4)-vegetated areas. Consistent with previous studies, A. albopictus males have their maximal dispersion in the first days after release, while in the following days the males become more stationary. The similar field performances obtained with marked and unmarked radio-sterilized and untreated A. albopictus males on similar environments confirm the negligible effects of irradiation and marking procedures on the quality of the males released. The similar sterile to wild (S/W) male ratio measured in high- and low-vegetation areas in the release sites indicates a similar distribution pattern for the wild and the released sterile males. According to the MRR data collected, the Lincoln index estimated different A. albopictus mean population densities in the study areas equal to 7,000 and 3,000 male/ha, respectively.

Automated summary

Mark-release-recapture (MRR) trials were conducted in Northern Italy to evaluate the survival, dispersal, and mating capacity of radio-sterilized Aedes albopictus males. Environmental factors such as barriers, shading, and vegetation seemed to have a greater influence on the survival and dispersal rates than weather parameters. The study confirmed a linear relationship between the daily survival rate of sterile males and relative humidity, and observed different dispersal capacities in low- and high-vegetated areas. The quality of the released males was not affected by irradiation and marking procedures. The data estimated different population densities of A. albopictus in the study areas.