The Impact of Foreign Mosquitoes on the Galapagos Islands

Different mosquito species draw from a variety of sources to get the blood they need for reproduction.  Some species choose mammals preferentially, while others prefer birds or even reptiles – interestingly enough, mosquito species seldom stray from their preferred feeding sources.

However, in the Galapagos Islands, one species of mosquito is exhibiting an unusual new behavior.  The Aedes Taeniorhynchus, or black salt marsh mosquito, has traditionally chosen mammals and birds for feeding.  Now, it has begun to feed on reptiles, particularly the Island’s famed marine iguanas and giant tortoises.

At first, it was thought that these mosquitoes were a new or foreign species that had been artificially introduced to the Galapagos Islands.  In fact, there are two species of mosquitoes found on the Galapagos Islands that have apparently been introduced by humans in recent memory.  Further research, however, has shown that these mosquitoes have actually been there for quite some time – possibly as long as 200,000 years.

Researchers believe that the fact that these black salt marsh mosquitoes have begun to change their feeding habits may be evidence that they are currently undergoing a period of evolutionary change.  The differences between the A. Taeniorhynchus mosquitoes found in the Galapagos and the A. Taeniorhynchus mosquitoes found on the mainland are so vast, that they can almost be classified as different species.  In fact, becoming a new species may be exactly what the Galapagos Island mosquitoes are doing.

The real threat is that with tourism increasing, a new mosquito species could easily be introduced to the Island, one that carries a disease that affects animals – particularly the reptiles or birds for which the Island is famous.  The wildlife of the Galapagos Islands is very isolated and has little resistance to disease.  This means that the introduction of a new disease could have serious and perhaps irreparable consequences, devastating this incredible natural resource.  All it would take is for one mosquito to catch a ride aboard a plane headed for the Galapagos and the remarkable wildlife there could be wiped out forever.

Right now, the government of Ecuador has begun requiring planes flying in to the Galapagos Islands to be treated with insecticides both inside the cabin and hold, and outside the plane as well.  Similar requirements have been suggested for ships, but none have so far been implemented, as many cruise lines are concerned about the cost and logistics associated with these processes.

Presently, researchers believe that the largest mosquito based threat to the Galapagos Islands is from foreign mosquitoes being introduced, rather than changes in the native mosquitoes.  Consequently, they plan to let evolutionary changes in the native mosquito run their natural course.  Hopefully they are right, and the steps the Ecuadorian government is taking to prevent the introduction of foreign mosquitoes will be effective.  Otherwise, the great ecological resource that is the Galapagos Islands could be wiped clean from the map, destroying a fascinating ecosystem that isn’t represented anywhere else in the world.