In evolutionary terms, every invasive species is extraordinary. Take an organism out of its native habitat that it’s specifically evolved to survive in over millions and millions of years, plop it somewhere new, and–by chance–it flourishes. Adding to the miraculousness: Invasive species often arrive in their new environments in initially small numbers, carrying far less genetic diversity than they have in their home range. A drop in genetic diversity, called a “genetic bottleneck,” means less potential for adaptability and flexibility in the face of challenges.
This is the genetic paradox of invasion; small, genetically homogenous groups of organisms, taken far from home, can still become pervasive pests. For example, the famous case of cane toads, brought to Australia to try to control insects munching on sugarcane crops, quickly became an-ever-expanding menace in their own right.
Clearly, many invasive species manage to thrive despite the evolutionary roadblocks, and cane toads aren’t the only interlopers disrupting the down-under ecosystem. New research of a stinging, buzzing environmental threat offers some insight into how and why.
Surprising selection
In a study published February 29 in the journal Current Biology, scientists cataloged the spread of Asian honey bees (Apis cerana) in Australia, and analyzed the invasive populations’ genetic journey. They found that the tens of thousands of hives now buzzing across northeastern Australia likely originated from a single bee colony (one breeding queen and her workers), introduced to a Queensland port around 2007. Despite that extreme initial genetic bottleneck, over the course of just 10 years, the insects started re-diversifying and adapting to their foreign habitat via natural selection, according to the research. One queen bee held enough genetic diversity to kickstart an entire, viable population. “Our data support the view that genetic bottlenecks may have…
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