Biological Invasions Can Begin With Just One Insect

A new study by York University biologists Amro
Zayed and Laurence Packer has shown that a lone insect can initiate a
biological invasion.
Zayed, a recent graduate of Packer's lab, examined patterns of genetic
diversity in both native European and invasive North American populations
of
a solitary bee. He concluded that the invasion was most likely founded by
one mated female. The study was published today in the open access journal
PLoS ONE.



"This is a shocking result, especially since bees suffer from huge genetic
problems in small populations," says Zayed, now a postdoctoral fellow
in the Department of Entomology at the University of Illinois.



"We're now seeing that the introduction of even one single insect can
cause a potentially costly invasion, so we have to be extremely vigilant
with reducing the number of animals that are unintentionally transported
around the globe," he says.



The study contradicts a popular theory of invasive biology: the more
individuals introduced to an area, the higher the success of the invasion.
This
concept is commonly referred to as the "propagule pressure hypothesis."



Zayed adds that numbers are not the only factor controlling the success of
invasions. "Chance and the specific characteristics of invasive species
and their introduced habitats can be more important," he says.



Packer, a professor in York's Department of Biology, notes that exotic
invasive species are considered a major threat to biodiversity
conservation,
and can cause huge economic losses.



"Understanding how exotic species establish and spread in their new
habitats is the first step to solving the invasive species problem,"
Packer
says.





York University is the leading interdisciplinary research and teaching
university in Canada. York offers a modern, academic experience at the
undergraduate and graduate level in Toronto, Canada's most international
city. The third largest university in the country, York is host to a
dynamic academic community of 50,000 students and 7,000 faculty and staff,
as well as 200,000 alumni worldwide. York's 11 faculties and 24 research
centres conduct ambitious, groundbreaking research that is
interdisciplinary, cutting across traditional academic boundaries. This
distinctive and
collaborative approach is preparing students for the future and bringing
fresh insights and solutions to real-world challenges. York University is
an
autonomous, not-for-profit corporation.





Citation: Zayed A, Constantin SЛ›A, Packer L (2007) Successful Biological
Invasion despite a Severe Genetic Load. PLoS ONE 2(9): e868.
doi:10.1371/journal.pone.0000868


Please click here.


PLoS ONE is the first journal of primary research from all areas of
science to employ both pre- and post-publication peer review to maximize
the
impact of every report it publishes. PLoS ONE is published by the Public
Library of Science (PLoS), the open access publisher whose goal is to make
the world's scientific and medical literature a public resource.


plosone


Public Library of Science

185 Berry Street, Suite 3100
San Francisco, CA 94107

USA