In 1920, the Eastern gambusia, also known as the mosquitofish, was introduced from the United States into Spain to control the population of mosquitoes and other insects containing malaria and other diseases. However, the species soon backfired as it had damaging effects on the local food chain, preying on predators and taking food supplies from other insects, thus earning its position among the 100 Most Harmful Invasive Exotic Species list, according to IUCN. The key to the mosquitofish’s success lies in its genetic variability, and ability to adapt quickly to changing external circumstances.

This article makes a really good point that can be witnessed in many similar situations as well. Just because a species does really well in balancing one ecosystem, this doesn’t mean that it will provide the same services for a different ecosystem. We have come a long way in science in understanding biodiversity and the complexity of the food web, but we will never understand just how truly susceptible it is to every minor change; therefore, we cannot make assumptions and add or subtract species, relying on our limited knowledge of that ecosystem to make possibly damaging decisions. Particularly species like the mosquitofish, which are very varied genetically, can become almost an entirely new species in a short amount of time and will thus contribute an unpredictable effect to their surrounding environments just a few years down the road.

Vera, M. (2016, July 12).The Invasive Success of the Mosquitofish is Due to its Genetic Variability. Phys.Org. Retrieved November 19, 2016, from http://phys.org/news/2016-07-invasive-success-mosquitofish-due-genetic.html.