On the island of Procidain Campania, the project has been active since 2015 STOP IGREone of the few in Italy who aims to control the local population of Asian tiger mosquito (Aedes albopictus) which is a pest in the area and, for several years, in many parts of Italy, creating problems for all those who practice outdoor activities during the day. The experiment, co-financed by the INF-ACT Foundation thanks to a PNRR funding for the study and fight against emerging infectious diseases, including those transmitted by insect vectors, consists in the introduction on the island of large quantities of sterile male tiger mosquito individuals generated in the laboratory. The first sterile male tiger mosquitoes have been introduced to the island at April 2024 and, so far, the experiment seems promising: the results are very good (the tiger mosquito population has been reduced by 50%) and the procedure does not pose any specific risks to the environment in addition to being reversible (as soon as the release of sterile males is stopped the population resumes its normal growth). For this reason the STOPTIGRE project, which boasts among other things an important component of citizen scienceit is expected repeatable in larger areas.
What does the STOPTIGRE project consist of?
The STOPTIGRE Project aims to monitor and especially control the tiger mosquito on the island of Procida, a place where this species has caused many problems for the population in recent years, making daily activities such as growing vegetables or taking care of private gardens difficult.
The project was born from the collaboration between the Department of Biology of the University of Naples Federico II and the Municipality of Procida, massively involving local citizens, schools and associations of the island. For example, the collection of preliminary data that allowed the planning of the entire project was carried out through citizen science.
Marco Salveminithe researcher in charge of the project, explained to us in detail what the phases of the StopTigre experimentation are:
The experiment is divided into 6 phases: preliminary assessment; monitoring and analysis of the local population of tiger mosquitoes present in the study area, with the help of local citizens and use of ovitraps; experiment of releasing sterile males and their recapture; involvement of schools to raise awareness among children, who in turn will talk to their parents at home about what they have learned; raising awareness among citizens for the elimination of larval development sites, i.e. sources of stagnant water that they usually keep in their gardens or homes; release of sterile males and suppression of the tiger mosquito population in the selected area.
To evaluate the effects of the experiment, together with an area where sterile individuals are released (in locations the Chiaiolella) there is also a control area (in the locality the Starza) where no sterile males are released. The control area is necessary for data comparison. Both areas extend for approximately 20 hectares.
Why the experimentation is taking place in Procida
The island of Procida has some peculiar characteristicswhich is why it was chosen as the first physical location for the activation and testing of the STOPTIGRE protocol. First of all, being a very small island (4 km2) allows the concrete control of some areas. It is also an island densely populated and is very visited by tourists and above all is the seat of a major tiger mosquito infestationlike all the coastal regions of southern Italy.
How Sterile Male Tiger Mosquitoes Are Produced
They are made to develop some sterile males in the laboratory (generated in Emilia-Romagna by the Agriculture and Environment Centre “Giorgio Nicoli”) and then released into the environment in large quantities, to compete with fertile males. The female mosquitoes that mate with sterile males will not have offspring, thus obtaining control of the population and above all its noticeable reduction.
These male mosquitoes are irradiated with the X-raysand in this way the spermatozoa are rendered non-functional. The female will tend to choose the sterile male, and not the fertile one, for a mere question of statistics, in fact as many sterile males as possible are released.
What results have been achieved so far?
One of the encouraging results what the team from the Federico II University has found is that from April to July 2024 a reduction in the tiger mosquito population at Chiaiolella of approximately 50% compared to the population of the control area. An important result if we consider the impact on local inhabitants and the liveability of the area.
Prospects for the future
This Project could be a pioneer of others in the future that would also free the Islands of Capri and Ischia (also part of the Campania archipelago) from the plague of the Tiger Mosquito. According to Salvemini:
In this way, Campania could become the first region in the world to have used innovative biotechnological and eco-sustainable tools and to have obtained liberation from the tiger mosquito, also through the continuous and active participation of citizens.
