Development of sexing systems functional to mass production of Aedes albopictus Skuse sterile males

Methods currently used to control Aedes albopictus Skuse are not only insufficient to ensure its reduction under acceptable sanitary threshold, but they are also sources of environmental pollution. For these reasons, over years many studies have been carried out to find alternative methods to control this insect vector able to transmit Dengue, Chikungunya, Zika and Yellow Fever viruses. One of the possible environmentally friendly alternatives for the control of Ae. albopictus is the sterile insect technique (SIT) which involves the release of adult males, previously treated with ionizing radiations in order to induce sterility into the wild population. Continuous releases of sterile males, in combination with traditional control strategies could be a valuable tool to suppress or eradicate the wild population, especially in those areas where Ae. albopictus represents a newly imported invasive species that is not yet heavily spread into the territory. However, the presence of females in the SIT release campaigns must be avoided or strongly reduced. In fact, even if completely sterilised, the females maintain their feeding activity and vectorial capacity. Moreover, their presence in the released insects can affect the dispersal and mating rates of the males, thus reducing the cost effectiveness of the SIT. Sex separation of Ae. albopictus can be effectively achieved by exploiting different biological traits between males and females at either pupal or adult stage such as protandry, dimorphism or by investigating classical non transgenic genetic sexing strains. Currently the available sexing methods are not mechanized and are based on manual procedures, therefore they are not capable to assure an effective separation and are strongly affected by operator procedures. My PhD project, here presented, has the purpose to investigate new methods for an effective and reliable sex separation of Ae. albopictus at different stages in accordance with the European regulations, which limits the creation and use of genetic modified strains. The implementation of a hyper-proterandry strain through a classical cross-breeding method and the production of an optical sexing system integrated with an artificial intelligence able to sort sexes at adult stage are the main lines of investigation during my current studies within the PhD in Health, Safety and Green Systems.