A team of Spanish researchers led by the Universidad de Murcia and collaborating with the citizen science platform Mosquito Alert (coordinated by CREAF and CEAB-CSIC and supported by Obra Social “la Caixa”) have published a map showing the known distribution of the tiger mosquito through 2015. After inspecting more than 200 zones and confirming its presence in Cadiz, Lleida, and Huesca, the study demonstrates that the invasive mosquito has completed its colonisation of the arc of the Spanish Mediterranean coast and continues to advance towards the interior.
In just one year the tiger mosquito arrived to 70 new municipalities, three provinces (Huesca, Lleida, and Cádiz), and the islands of Menorca and Formentera as described in a recent study published in the journal Acta Tropica which includes an updated map of the distribution of the tiger mosquito using data from 2004-2015. Since the first cases of the detection of tiger mosquito in 2004 until 2015, the presence of the tiger mosquito has been confirmed in a total of 540 spanish municipalities.
The study was carried out by a team of scientists from Spanish institutions and centers led by Francisco Collantes from the Department of Zoology and Physical Anthropology at the University of Murcia. “We have confirmed that the tiger mosquito has maintained its establishment in places where it was in previous years, above all along the coast. It has also colonised new areas,” says Dr. Collantes, while recognising that these findings were fairly predictable since “the [new] areas where we have run into the tiger mosquito are extensions of the borders and the in-between spaces that remained to be filled in.” Some of the new mosquito inspections were based on reports from citizens using the Mosquito Alert app. “This study shows clear contributions to science from thousands of people participating in this platform, as well as other collaborating individuals and institutions,” says Aitana Oltra, Coordinator of Mosquito Alert. In fact, in 2015 the Mosquito Alert platform, coordinated by CREAF and CEAB-CSIC with the support of Obra Social “la Caixa”, published more than 1,700 confirmed citizen observations of tiger mosquitos on the project map (www.mosquitoalert.com).
With the support of a Spanish national research program managed by the Ministry of Economy and Competitiveness, in 2015 the team of researchers inspected 237 municipalities and detected the tiger mosquito in 112 of these. Some of these discoveries helped to demonstrate that the mosquito has expanded its range in areas where it was already established such as Murcia and the province of Valencia, while others served to show the new establishment of the mosquito in regions such as Basque Country.
According to Dr. Collantes, the tiger mosquito has been able to gain ground so quickly due to human activities and transport, though he also cites a “snowball effect.” “With more and more area occupied by the mosquito the artificial movements also become more likely, accelerating the colonisation process.”
A network of volunteer detectives help scientists trap the invasive mosquito
According to the researchers, one of the most unexpected discoveries in 2015 was in the city of Huesca where winters are very cold. After receiving a citizen report via the Mosquito Alert app the scientists travelled to the area and confirmed the sighting with traps. However, “we will have to wait until inspections next year to confirm whether the tiger mosquito has become established or if it was just a chance case,” says researcher Sarah Delacour from the University of Zaragoza. As a result of this finding, for the 2016 tiger mosquito control campaign the regional government of Aragon initiated a vigilance network in its three provinces in order to stay up to date on the situation.
Something similar happened in the province of Lleida when in 2008 the invasive insect was found in a tire warehouse in the municipality of Maials. “The rapid response removed all traces of the mosquito for years, until 2015 when citizens found it in Tárrega and reported it with the Mosquito Alert app,” explains Dr. Frederic Bartumeus, ICREA CEAB-CSIC and CREAF researcher and director of Mosquito Alert. After carrying out an expedited sampling, the scientists confirmed that “the tiger mosquito had returned to the Lleida region and was definitively established, this time in urban areas,” explains Dr. Roger Eritja, entomologist from Mosquito Alert and the Servei de Control de Mosquits del Baix Llobregat.
In 2014 citizens detected the first tiger mosquito in the region of Andalusia in the municipality of Malaga. Since then, a number of reports have been issued from Southern Spain, and for this reason the study made special efforts to inspect more areas of Andalusia. With this effort, it has been confirmed that the insect is now established in that region of the Iberian Peninsula, and Cadiz is also added to the list of affected provinces.
Expanded in Catalonia and the Balearic Islands
With confirmation that the mosquito is already established in the province of Lleida, all four of Catalonia’s provinces are now affected by the invasive insect. Additionally, though less expected due to climatic conditions, its presence has also been confirmed in the foothills of the Pyrenees within the provinces of Barcelona and Girona.
In the 2015 map, red colour denoting establishment of the mosquito continues to creep over the Balearic Islands. Just as happened the year before on the islands of Mallorca and Ibiza, Menorca is now colonized by the tiger mosquito. Also, in 2015 it was found for the first time on Formentera. Some of the inspections have been carried out with the collaboration of the MHSSE program, local vigilance programs in Mallorca and Menorca, and monitoring carried out by the Eivissa and Formentera governments together with the TRAGSA public corporation conglomerate.