New research on the southern small white butterfly shows that humans have forced this species, as well as others to move further afield in recent years, since by changing large areas of land for our own use other creatures are being left with no choice but to adapt.
The Butterfly Makes a Surprise Journey
The southern small white butterfly, a close relative of the large and small cabbage whites, was only known in Switzerland from isolated population in Valais and Ticino until just a few years ago. But in 2005, the Mediterranean species started moving north and east; it turns out that their reange now extends up to and even into the North Sea, as well as all the way to Czech absurdities.
The sudden and homogenizing nature of this range expansion was further revealed by a surprising genetic snapshot from the newly colonized areas, where butterfly populations now showed much less genetic diversity. This process involved comparing the genetics of butterflies caught more recently during the invasion to those from older museum specimens available prior to the invasion by researchers at the University of Basel, in collaboration with the University of Greifswald and Senckenberg German Entomological Institute.
The Role of Urbanization
Among other things, the crayfish study revealed that attracted to certain human-made environments — in this case boats and docks — rather than spreading on its own via natural waterways.Photo: Getty ImagesThe garden is one of the many habitats whose selection, along with a propensity for people’s gardens to overlap, catapulted the southern small white across continents. The southern small white is quite unlike the many butterflies that like to make epic migrations, instead living out their brief lives fluttering in a relatively small area near where they hatched — among arugula and candytuft, plants that grow plentifully within flying distance during their three-week lifespan.
The increasing urbanization of the countryside has offered an environment where southern small white has been able to prosper, as candytuft is a plant widely found in gardens and other settled areas. The butterfly can produce five to six generations each year, all of which let it quickly come about in newly colonized regions and further spreading.
Conclusion
From a conservation perspective the spread of the southern small white butterfly is a two-edged sword. The species may be less likely to go extinct because of this larger population, but concern is now heightened over loss of genetic variability that has resulted from the many thousands that have been added. This is because the researchers assert that this loss of diversity from original populations, induced directly by human-driven expansion of the built environment, raises a point unprecedentlyad. As the butterfly spreads further, scientists look into both the underlying causes as well as the potential long-term effects on genetic health.
