Monday, November 27, 2017 by Frances Bloomfield
Nature may no longer be the primary force impacting evolution. A duo of researchers from the University of Toronto and Fordham University have put out a revolutionary new study on the evolutionary influence of urbanization. The study, which was published in Science, serves as a grim reminder on how far-reaching man’s power truly is.
For the purposes of their research, study co-authors Marc Johnson and Jason Munshi-South pored through over a hundred global studies, all of which focused on urbanization or evolution. They compiled dozens of examples that demonstrated clear connections between the mechanisms of evolution and citification.
Bedbugs were one such case. As Johnson explained: “Bedbugs, for example, were scarce two decades ago, but they’ve adapted to the insecticides used to keep them at bay and have exploded in abundance worldwide.” (Related: Super bedbugs now emerging everywhere thanks to global travelers who carry the pests at the speed of jet travel.)
One other example cited by the researchers was that of mosquitoes in the U.K. that have since adapted to the London Underground. Known as the London Underground mosquito, this distinct subspecies of insects has no need for blood in order to produce eggs, nor do they need to hibernate during winter like many other species of mosquitoes. They’re known to harbor a variety of diseases, however, and have proliferated in the subways of New York, Chicago, and Los Angeles.
“It’s good news that some organisms are able to adapt, such as native species that have important ecological functions in the environment. But it can also be bad news that the ability of some of these organisms to adapt to our cities might increase the transmission of disease,” said Johnson.
In addition to London Underground mosquitoes, white-footed mice are another common city animal linked to the spread of disease. To be more precise, white-footed mice are known to be one of the key carriers of Lyme disease-carrying ticks. These rodents also exist in various populations throughout the numerous parks of New York City. And in 2012 alone, there were over 2,044 reported cases of Lyme disease in the state of New York, making it one of the top 13 states with Lyme for that year.
Because of this, Johnson and Munshi-South have recommended that greater thought be placed on the planning of cities, not just for the sake of animals but for ours as well. Cities are unique ecological niches with characteristics that make them ideal for wild creatures, mostly due to there being a constant food supply. From devices like bird feeders to the huge amounts of food waste we put out daily, we’ve made it easier for animals like rats, pigeons, and raccoons to thrive in urban sprawl. By contrast, some animals are unable to acclimate to the challenges presented by a new habitat and may end up dying off instead.
“We’ve created a novel ecosystem that no organism has ever seen before,” said Johnson, who then went on to call their results a “wake-up call for the public, governments and other scientists.”
Munshi-South added: “Traditionally, we’ve thought about evolution as a long-term process driven by environmental pressures and the interactions between species. But now there is a new driver that is rapidly changing many other species, which is how they interact with humans and our built environment. Humans and our cities are one of the most dominant forces of contemporary evolution now.”
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