Solar panels could be a threat to aquatic insects, new research
shows
Scientists urge caution after finding that insects fall into
'ecological trap' by mistaking panels for pools of water Solar panels
could wipe out fragile populations of insects, according to a new study
that raises fresh doubts about the ecological impact of some forms of
renewable energy.
Scientists have discovered that aquatic insects such as the mayfly
can mistake shiny photovoltaic panels for pools of water, which they
rely on to reproduce. They urge caution on the increasing use of panels
until experts work out how they could affect insects and other creatures
that feed on them.
"The effect of solar panels on populations of aquatic insects has not
yet been researched," said Bruce Robertson, a scientist at the US
Department of Energy's Great Lakes Bioenergy Research Centre in
Michigan. "It is clear that the worst place to put a solar installation
would be in proximity to natural lakes and rivers, where aquatic insects
could easily become attracted to them." The insects mistake the panels
for water because both reflect horizontally polarised light - an optical
trick in which light waves vibrate in the same direction. Many insects
have evolved to detect such polarised light as a sure way to find water,
particularly in arid environments.
The insects mate above the panels, which makes them vulnerable to
predators, and lay their eggs on their surface, where they perish.
Scientists call such natural siren songs "ecological traps".
Robertson said: "There is no more severe way to degrade an organism's
habitat than by creating an ecological trap.
We predict traps should cause rapid population declines where solar
panels are common, but it will depend on the extent of solar panels in
an area and how many insects are attracted to them. It appears that,
once attracted, most die trying to reproduce." To investigate the scale
of the effect, Robertson and colleagues in Hungary set up different
designs of solar panels next to a creek in the Hungarian Duna-Ipoly
National Park at Domorkapu. They watched insects such as mayflies and
stoneflies form swarms to reproduce in the early summer evening.
Reporting their results in the journal Conservation Biology, the
scientists say that several species of insect were drawn to the panels
and laid more eggs on their surface than on water. They add: "We urge
caution in the placement of solar arrays and selection of panel design,
particularly where rare or endangered species may be directly or
indirectly affected." Solar farms, with large areas of such panels, are
rapidly spreading across Europe, Africa and the US, they say.
The scientists found that solar panels which had their shiny surface
broken up with white borders or grid designs proved much less attractive
to the insects. "They still polarise light, but produce it in smaller
patches which is unappealing to aquatic insects that may prefer larger
patches of water in which to breed," Robertson said.
"Citizens concerned about the effect of their own solar panels or
collectors can use white tape to create a grid on their panels."
Guardian.co.uk
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