Mosquitoes evolved to threaten wildlife on Galapagos Island

The Galapagos giant turtle and other typical wildlife are facing new diseases when the island's mosquitoes suddenly change the source of food to reptile blood.

Some scientists from Leeds University, London Animal Association (ZSL) and Galapagos National Reserve have discovered that the black brackish water mosquito (Aedes taeniorhynchus) living on Galapagos Island has changed its habit. to feed on reptiles, mainly on giant Galapagos turtles and sea iguanas , while their ancestors only preferred mammalian blood and some birds.

The finding raises concerns that these changes could destroy the unique diversity of the Galapagos wildlife world if a new disease caused by mosquitoes appears. That concern is very easy to come true in the context of tourists rushing to this island.

With the use of gene technology, researchers have shown that this mosquito has lived in the Galapagos since 200,000 years ago, not just beginning to appear with the presence of people on the island like people still think. The study also found that unlike land-based mosquito populations that often live in mangroves and salt fields along the coast, Galapagos mosquitoes can encroach up to 20 km inland and occupy a height of 700 meters. The research team believes that the change in the habit of feeding is an adaptation of mosquitoes to life on the island in the context of a decrease in the number of mammals. This started happening before people arrived on the island 500 years ago.

'At the beginning of the study, we thought that this mosquito was brought here by humans, we were surprised to discover the long history of Galapagos mosquitoes,' said Arnaud Bataille, graduate student. Leeds University and ZSL, a research team member, said. 'The genetic differences of Galapagos mosquitoes are so great that they are different animals, which suggests that Galapagos mosquitoes are in the process of evolving into one. new species. '

Galapagos giant tortoise.(Photo: Penelope Curtis)

Mosquitoes are the vectors of most dangerous wildlife diseases, such as bird malaria or West Nile virus fever. While there is no evidence that these diseases are currently present in the Galapagos, the mosquito's dense distribution and the fact that they feed on many island animals can very well be means that any invasive disease will spread quickly to many different species.Due to being completely isolated from the outside world, Galapagos species are hard to acquire immunity to new invasive diseases , so the effects of these diseases can be terrible.

'With the number of tourists increasing rapidly, which means more flights to the archipelago, the risk of mosquitoes on the aircraft carrying the disease from the continent to the island also increases,' said Dr. Andrew Cunningham of Hiep. Animal Society of London, one of the study authors said. 'If a new disease spreads to the island through this way, Galapagos mosquitoes will quickly bring the disease and spread to every corner of the archipelago.'

Instead of implementing management measures for Galapagos mosquitoes, the team believes that measures should be taken to prevent new diseases from reaching the islands.

The Ecuadorian government recently demanded that planes land on Galapagos, forcing the aircraft to have residual mosquito killer on the inside surfaces of the aircraft, and to conduct spraying in the cavity before each flight. At the same time, the same measure has been applied to vessels arriving at Galapagos.

Dr Simon Goodman, a member of the research group, a faculty member of the University of Leeds's Department of Biology, said: 'It is important that these measures are maintained regularly and conducted strictly, if not consequences. will be really unpredictable. '

References:
Natural colonization and adaptation of a mosquito ở trong Galapagos and its implications for disease threats to endemic wildlife.Proceedings of the National Academy of Sciences, DOI: 10.1073 / PNAS.0901308106