Stowaway insects imperil Darwin's finches

Andy Coghlan, New Scientist 12 Aug 09;

The famous Galapagos finches could be among the first casualties of mosquitoes that are stowing away on aircraft, potentially bringing fatal viruses to the islands.

Live mosquitoes captured in the holds of aircraft arriving on the Galapagos from mainland Ecuador were found to survive and breed on the islands. Although none of the captured mosquitoes carried lethal viruses such as the West Nile virus (WNV) – which decimated bird populations in the US after arriving in New York in 1999 – they have the potential to do so.

WNV has been reported in Colombia and Argentina, and could have reached Ecuador, says Simon Goodman of the University of Leeds, who co-led the research team. It is not only the finches that are at risk. "West Nile virus also affects reptiles and mammals, and so could impact other iconic Galapagos species such as marine iguanas and sea lions," Goodman says.
Wildlife threat

Goodman and his colleagues found 74 live insects after searching the holds of 93 aircraft landing on Baltra Island in the Galapagos. Of these, six were Culex quinquefasciatus mosquitoes, which transmit WNV and the parasite that causes bird malaria. Two more were caught in aircraft that landed on nearby San Cristobal.

"The consequences for wildlife could be severe," says Marm Kilpatrick of the University of California, Santa Cruz. The findings are probably an underestimate of the true numbers of mosquitoes arriving, he says.

By comparing genes from mosquitoes caught on the mainland with those on the Galapagos, the researchers were able to show that arrivals from Ecuador survive and breed with Galapagos mosquitoes.

Goodman recommends stepping up the spraying of aircraft with insecticide before they leave mainland Ecuador.

Journal reference: Proceedings of the Royal Society B, DOI: 10.1098/rspb.2009.0998

Galapagos face ecological disaster due to tourism: study
Yahoo News 12 Aug 09;

LONDON, (AFP) – Mosquitoes brought into the Galapagos on tourist planes and boats threaten to wreak "ecological disaster" in the islands, central to Darwin's theory of evolution, a study said Wednesday.

The insects can spread potentially lethal diseases in the archipelago off Ecuador's Pacific coast, used by Charles Darwin as the basis of his seminal work "On the Origin of Species by Means of Natural Selection".

"Few tourists realise the irony that their trip to Galapagos may actually increase the risk of an ecological disaster," said Simon Goodman of Leeds University, one of the study's co-authors.

"That we haven't already seen serious disease impacts in Galapagos is probably just a matter of luck."

The study found that the southern house mosquito, Culex quinquefasciatus, was regularly hitching rides on planes from the South American mainland, and island-hopping on tourist boats between the different islands.

Species threatened by diseases such as avian malaria or West Nile include the islands' best-known residents, its giant tortoises, as well as marine iguanas, sea lions and finches.

Arnaud Bataille, another researcher on the eight-page study, said: "On average the number of mosquitoes per aeroplane is low, but many aircraft arrive each day from the mainland in order to service the tourist industry."

Worse, "the mosquitoes seem able to survive and breed once they leave the plane," he added.

Goodman noted that Ecuador recently introduced a requirement for all aircraft flying to the Galapagos to have insecticide treatment, but said similar moves are needed for ships, and the impact needs to be evaluated.

"With tourism growing so rapidly, the future of Galapagos hangs on the ability of the Ecuadorian government to maintain stringent biosecurity protection for the islands," he said.

The study, co-authored by Leeds University, the Zoological Society of London, the University of Guayaquil, the Galapagos National Park and the Charles Darwin Foundation, was published in the journal Proceedings of the Royal Society, Britain's de-facto academy of sciences.

Some 10,000 people, mostly fishermen, live on the volcanic Galapagos archipelago, which rose from the Pacific seabed 10 million years ago and became famous when Darwin visited to conduct research in 1835.

Stowaway mosquitoes threaten Galapagos wildlife
Ben Hirschler, Reuters 12 Aug 09;

LONDON (Reuters) - The unique wildlife of the Galapagos Islandsis under threat from disease-carrying mosquitoes arriving on board growing numbers of aircraft and tourist boats, researchers said on Wednesday.

Experts fear the spread of the southern house mosquito, or Culex quinquefasciatus, could have the same devastating effect in the Galapagos as in Hawaii during the late 19th century, when disease wiped out many indigenous birds.

The mosquito was first spotted in the Galapagos in the mid-1980s, but its presence then was considered a one-off.

Now research by British and Ecuadorean scientists has found the insects are, in fact, transported regularly by plane and are island-hopping on boats, spreading throughout the archipelago.

Genetic tests also confirm they are able to survive and breed once they arrive at their new home.

"More ships and more aircraft are coming to the Galapagos every year and the risk of something being introduced is growing all the time," said Leeds University researcher Simon Goodman.

"That we haven't already seen serious disease impacts in Galapagos is probably just a matter of luck." The southern house mosquito is a carrier of diseases including avian malaria, avian pox and West Nile fever.

It was brought to Hawaii in water barrels on whaling ships, leading to diseases that are blamed for wiping out many bird species. Only 19 out of 42 species and subspecies of honeycreeper now remain in Hawaii.

Goodman and colleagues, who published their findings in the Proceedings of the Royal Society, fear everything is in place for a similar wipe-out in the Galapagos, given the rapid growth in transport links with the mainland.

Tourism is a major source of income for the Galapagos and is growing by around 14 percent a year.

The government of Ecuador recently introduced a requirement for insecticide spraying on aircraft flying to the Galapagos, but the scientists said the scheme's effectiveness was not being monitored and the rules did not apply to cargo ships.

Mosquitoes are the latest in a string of invaders -- including rats, wild pigs, flies and invasive plants -- that have colonized the Pacific islands, located about 600 miles off South America's coast along the equator.

British naturalist Charles Darwin developed his theory of evolution in the 19th century after studying the islands' unique animal population.