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<h1><b>Inbred bumblebees 'face extinction threat'</b></h1>By Mark Kinver
Science and environment reporter, BBC News <br><br>
<b>
<a href="http://www.bbc.co.uk/news/science-environment-11199779" eudora="autourl">
http://www.bbc.co.uk/news/science-environment-11199779<br><br>
</a>Some of the UK's rarest bumblebees are at risk of becoming extinct as
a result of inbreeding, research suggests.<br><br>
</b>The lack of genetic diversity is making the bees more vulnerable to a
number of threats, including parasitic infection, say scientists in
Scotland.<br><br>
They warn that some populations of bees are becoming increasingly
isolated as a result of habitat loss.<br><br>
The findings are being presented at the British Ecological Society's
annual meeting at the University of Leeds.<br><br>
Lead researcher Penelope Whitehorn, a PhD student from Stirling
University, said the study of moss carder bumblebees (<i>Bombus
muscorum</i>) on nine Hebridean islands, off the west coast of Scotland,
offered an important insight into the possible consequences of
inbreeding. <br><br>
"The genetic work had already been carried out on these bumblebees,
so we knew that the smaller and more isolated populations were more
inbred than the larger populations on the mainland," she told BBC
News. <br><br>
"And as it was an island system, it could work as a proxy for what
could occur on the mainland if populations do become isolated from each
other as a result of habitat fragmentation."<br><br>
The study is believed to be the first of its kind to investigate
inbreeding and immunity in wild bees.<br><br>
<b>Uncertain future<br><br>
</b>Ms Whitehorn found that, although the inbreeding did not seem to
affect the bees' immune system directly, it did make the insects more
susceptible to parasitic infection.<br>
The ideal habitat on the Hebridean islands offers the resident bee
populations a fighting chance <br><br>
"We found that isolated island populations of the moss carder
bumblebee with lower genetic diversity have an increased prevalence of
the gut parasite <i>Crithidia bombi," </i>she explained. <br><br>
"Our study suggests that as bumblebee populations lose genetic
diversity the impact of parasitism will increase, which may increase the
extinction risk of threatened populations."<br><br>
She added that the populations of the bees on the islands were
"quite healthy because the habitat was so good", but inbreeding
did have a range of other consequences, such as the production of
infertile males.<br><br>
"If inbreeding occurs on mainland Britain, where the habitat is not
so good, then species may well be threatened," Ms Whitehorn
suggested.<br><br>
Other studies of invertebrates have found other costs as a result of
inbreeding, such as a loss of general fitness in the species in
question.<br><br>
Habitat loss is resulting in populations of bees becoming more and more
isolated from their neighbours, effectively leaving them as island
populations.<br><br>
Ms Whitehorn cited the example of the short-haired bumblebee (<i>Bombus
subterraneus</i>)<i>, </i>which finally became nationally extinct in the
late 1980s when a parasitic infection placed increased pressure on the
remaining populations, which were already vulnerable as a result of
fragmented habitats.<br><br>
To date, recent attempts to re-introduce the population back into the UK
from New Zealand - where it had been introduced from Britain in the late
19th Century, have not been successful.<br><br>
The Bumblebee Conservation Trust said efforts to conserve bumblebees were
vital as the creatures played a key role as pollinators, especially when
it came to wild flowers and commercial crops.<br><br>
The UK currently has 24 species of bumblebee, after seeing two species
become nationally extinct in recent decades. <br><br>
Of the remaining species, one quarter have been identified as being in
need of conservation to prevent them from disappearing from the British
landscape.<br>
<br><br>
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*************************<br>
Scott Hoffman Black<br>
Executive Director<br>
<b>The Xerces Society for Invertebrate Conservation<br>
</b>Chair<br>
<b>IUCN (International Union for Conservation of Nature) Butterfly
Specialist Group<br>
</b>4828 SE Hawthorne <br>
Portland, OR 97215 <br>
Direct line (503) 449-3792<br>
sblack@xerces.org<br><br>
<i>The Xerces Society is an international, nonprofit organization that
protects wildlife through the conservation of invertebrates and their
habitat. <br>
</i> <br>
To join the Society, make a contribution, or read about our work, <br>
please visit
<a href="http://www.xerces.org/">www.xerces.org</a>.<br><br>
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