Of all the hematophagous mosquitoes found in the Iberian Peninsula, perhaps one of the most dangerous for humans is the tiger mosquito , Aedes albopictus . It gets its name from the pattern of white stripes on its abdomen and legs, which contrasts with the black color of its body, and makes it easy to identify even for the untrained eye. To be a mosquito, it has a relatively large size, between 5 and 10 millimeters in length.
diseases vector
The female tiger mosquito, as happens with other species of mosquito, has a mouth apparatus, called a stylet, specialized in piercing the skin, as if it were a hypodermic needle, and sucking the blood of its prey, and that of the human being is part from the menu. In the process, the animal injects its heparin-rich saliva to prevent blood coagulation—something that would fatally clog the stylet.
Similar to what happens with other species of mosquito, female Aedes albopictus can be carriers of various pathogens, which enter their body from the blood of a sick person, and transmit it to other people through saliva. Among the diseases that they can transmit, especially in those places where they are endemic, are dengue, West Nile, chikungunya, Zika, yellow fever or Rift Valley viruses, as well as malaria plasmodium.
The tiger mosquito originates from Southeast Asia, a place where most of these diseases are not endemic; the reason why it is capable of transmitting them is because of its great similarity to other species of mosquitoes of the Aedes genus that are the original vectors of these viruses. The tiger mosquito is currently present throughout Asia, in Oceania, Africa, Europe, the two American continents and, more recently, also on many Pacific islands, where it has arrived thanks to the human hand.
Invasive species
Tiger mosquito eggs can be found in any body of standing water, from a pond to puddles or inside a tire filled with rainwater. In addition, they are resistant to drying out; when the water evaporates they remain attached to the surface and, if they come into contact with moisture again, they rehydrate and are ready to hatch.
This peculiarity makes the tiger mosquito a perfect candidate to travel as a stowaway in the transport of merchandise or ornamental plants —on the ground, or inside canes such as that of the so-called ‘lucky bamboo’, Dracaena snderiana , which so It became fashionable a few years ago. Of course, it can also be accidentally carried by people on their travels. These eggs can even be transported in the dried mud adhered to the sole of the shoe after a day in the field.
This capacity for massive colonization has given it the dubious honor of being part of the list of the hundred most invasive species in the world.
In Spain it was detected for the first time in August 2004, in Catalonia. In that first encounter, only two specimens were found: a male in the backyard of a home in San Cugat del Vallès, and a larva in a hole in a nearby tree. But, in less than two years, populations of adults and larvae had already been found, which confirmed the naturalization and subsequent invasion of the tiger mosquito in national territory.
Fighting the tiger mosquito
Various actions have been carried out to fight against this invasion, with more or less success. From the use of insecticides where the mosquito breeds —with the environmental impact on native insect populations— to the release of transgenic males —remember that males do not bite, and therefore do not transmit diseases—.
The transgene is lethal to females, but not to males. When they mate with wild females, they pass on their transgene to their offspring. The female offspring die, but the males will carry the transgene, passing it on to half of their offspring, and so on.
But getting transgenic mosquitoes capable of decimating invasive populations is not very useful if you don’t know where these mosquitoes’ breeding areas are or where they move. To discover this data, a 2013 project opted for a novel approach: citizen science.
citizen science
Citizen science is defined as scientific research in which society is actively involved in collecting data, conducting experiments, obtaining results or disseminating the conclusions.
A group of researchers from the Center for Advanced Studies of Blanes (CEAB-CSIC) in collaboration with the Center for Ecological Research and Forestry Applications (CREAF-CSIC) developed, in 2013, a mobile application, ‘Mosquito Alert’, which allowed Users collect and share data on the presence of the tiger mosquito, as well as potential breeding sites.
The participants in the research, through the App, send geolocated photographs that a team then verifies, to develop a map that allows precise and targeted actions to be carried out.
The project was not only a success in analyzing the invasion of the tiger mosquito and providing tools for the management and control of populations, but it has also become an important source of scientific information, with a colossal database of the presence of tiger mosquito, and almost 20 scientific articles published since 2014. In addition, it laid the foundations for the use of citizen science mobile applications for their application in the study of invasive species.
References:
Aranda, C. et al. 2006. First record and establishment of the mosquito Aedes albopictus in Spain. Medical and Veterinary Entomology, 20(1), 150-152. DOI: 10.1111/j.1365-2915.2006.00605.x
Delacour-Estrella, S. et al. 2014. First record of Asian tiger mosquito, Aedes albopictus (Diptera, Culicidae), in Anadalusia and first corroboration of the data from Tigatrapp application. Anales de Biología, 36. DOI: 10.6018/analesbio.36.16
Encarnação, J. et al. 2021. Citizen Science and Biological Invasions: A Review.
Frontiers in Environmental Science, 8.
Južnič-Zonta, Ž. et al. 2022. Mosquito alert: leveraging citizen science to create a GBIF mosquito occurrence dataset. Gigabyte, 2022, 1-11. DOI: 10.46471/gigabyte.54
Leta, S. et al. 2018. Global risk mapping for major diseases transmitted by Aedes aegypti and Aedes albopictus. International Journal of Infectious Diseases, 67, 25-35. DOI: 10.1016/j.ijid.2017.11.026
Wise de Valdez, M. R. et al. 2011. Genetic elimination of dengue vector mosquitoes. Proceedings of the National Academy of Sciences, 108(12), 4772-4775. DOI: 10.1073/pnas.1019295108
