The fauna of the Galapagos Islands is attracting tourists in even larger numbers. However, a mosquito carrying West Nile fever brought from the mainland with the tourists could prove more harmful to the animals than the tourists ever will.
In the year of the 200th anniversary of the birth of Charles Darwin, a study published in the journal “Proceedings of the National Academy of Science”, has concluded that the growth in the number of tourists visiting the Galapagos Islands raises the likelihood of mainland mosquitoes infected with avian malaria and West Nile fever making it to the archipelago.
Scientists fear that the endemic black salt marsh mosquito could pick up such diseases from mainland mosquitoes brought to the Galapagos on tourist ships and planes. Then the endemic mosquito would transmit the infections to the unique collection of animals on the islands.
The black salt marsh mosquito is found throughout the Galapagos and is highly unusual because it can feed on the blood of reptiles as well as mammals and birds. This means it could transmit introduced diseases to the islands' rarest animals such as the giant tortoise, the marine iguana, and the flightless cormorant.
Analysis of the black salt marsh mosquito's DNA found it must have lived on the islands for about 200,000 years. The same species of mosquito is found on the South American mainland where it thrives on the blood of birds and mammals but not reptiles. The Galapagos’ mosquito has clearly begun to evolve into a different species.
Further proof of this evolution is that the Galapagos mosquito has also adapted to living and breeding in inland sites and at relatively high altitudes. The mainland version lives by the coast in mangrove swamps.
Two other species of mosquito are found in the Galapagos but both are recent introductions and don't move much away from feeding on humans, so it’s believed they won't have a big impact on spreading disease to wildlife.
Scientists indicated that there should be a concerted effort to stop mainland mosquitoes being carried on ships and planes to the Galapagos Islands, whose unique fauna so inspired Charles Darwin in the 1830’s.
