Mosquitos – To kill or not to kill, that is the question.

The climate we live in today is one of change. There is a huge debate as to if that change is for the better or worse, but the fact remains the climate is changing. This is not a new phenomenon. The climate has radically changed since the beginning of life some 3.6-3.8 billion years ago. However, no single species has ever been directly responsible for changing the climate – until Homo sapiens rocked up. We are changing the climate so quickly evolution can’t keep up. This means many species are struggling to survive, leading to a significant number of species extinctions. We are very quick to jump to the needs of endangered species, particularly those that are beneficial to us. But what about the species we don’t like? What about mosquitos? How many times have you been on holiday and got a nasty bite, or been forced to religiously take anti-malaria tablets? Mosquitos are irritating disease spreaders, so why don’t we just get rid of them?

When a species is under threat of extinction the typical conservation biologist’s argument is that the species must be conserved because of the impact its removal would have on the ecosystem. But what would happen if we made mosquitos extinct? Mosquitos as we know them have been around for roughly 95 million years. As a result they have well defined interactions with many species. Without mosquitos, some predators would not have prey and some plants would not be pollinated. As with all matters of conservation, the value of the species must be quantified. But the value of mosquitos is highly variable, dependent on the species in question. Often the value of the species to humans is considered most important. Mosquitos have little, if any benefit to humans, direct or otherwise. Furthermore, the theory of evolution would suggest, any niches currently occupied by mosquitos would soon be taken up by other insects.

Findings published this week in “The Lancet” suggest malaria killed a staggering 1.2 million people in 2010. This result emphasises the urgent need for mosquito control and perhaps extinction. The concept of mosquito eradication is not a new one. Many attempts have been made around the world, most famously being the use of DDT in America in the 1940s. In 2010, worldwide malaria control cost around US$1.88 billion for insecticides and $2.09 billion for nets, again emphasising the need for mosquito control. With advancing technologies alternative controls are beginning to be developed and tested. These include RNA interference, male sterilisation and improved chemicals.

Returning to the concept of a world without mosquitos, the result would be a huge reduction in the number of people dying of mosquito-transmitted diseases. This would mean even greater human populations in malaria stricken regions. While many of these countries can barely cope with the social and economic costs of their current population sizes, these costs are unlikely to outweigh the benefits of a larger but healthier population. It seems there is a touch of irony that we are more than capable of threatening the extinction of a species beneficial to us, such as tuna, but we are unable to impact mosquito populations, which come at such a devastating cost to human life.