This is a neat trick that hopefully applies to many other insects.
Importantly it establishes immediate warning of a pending infestation
allowing timely response. Something like this has great promise for
field work generally.
It may even allow trees to be inoculated just as they come under
attack. This avoids a meaningless late discovery when the tree is
beyond saving. Again we see the pressing need for boots on the
ground in all wood lots.
Most everything that afflicts a tree usually manifests itself on a
single branch whose timely pruning ends the danger. Black rot on a
plum tree is a classic example. One or two nips a year is good enough
to maintain a healthy tree for years.
In this case going about and setting traps is easy. At least it
should suppress the infectation.
Decoys could blunt
spread of ash-killing beetles
by Staff Writers
University Park, PA (SPX) Feb 21, 2013
As the emerald ash
borer ravages North American ash trees, threatening the trees' very
survival, a team of entomologists and engineers may have found a way
to prevent the spread of the pests.
Emerald ash borers
(EABs), a type of beetle native to Asia, first appeared in the U.S.
about 20 years ago. They are now moving east from Michigan, killing
ash trees on the Eastern Seaboard as far south as North Carolina.
"Within 25 years,
practically no ash trees may remain on either side of the St.
Lawrence Seaway," said Akhlesh Lakhtakia, Charles Godfrey Binder
Professor of Engineering Science and Mechanics at Penn State.
As their name implies,
emerald ash borers are iridescent green. The beetles don't carry
disease, but their larvae feed on the ash trees' sap, effectively
killing the trees by depriving trees of their nourishment.
Thomas C. Baker,
Distinguished Professor of Entomology at Penn State, knew that the
male EAB locates a mate by flying over an ash tree, finding a female
by identifying her green wings, which are folded over her back, and
then dropping straight down onto her.
Baker and a
post-doctoral fellow in his lab, Michael J. Domingue, were using dead
female EABs for bait to trap the male beetles. Dead EAB decoys are
not ideal for trapping, said Baker, because they are fragile and can
sometimes disappear from the trap.
Baker then learned
that Lakhtakia was able to replicate certain biological materials,
such as fly eyes and butterfly wings. Baker posed the question: could
Lakhtakia's technique visually replicate the unique female borer to
create a better lure?
The two researchers,
working with a graduate student in Lakhtakia's lab, Drew P. Pulsifer,
created a mold of the top of the female beetle's body. The decoy
beetle is made by a process of layering polymers with different
refractive indexes to create the desired iridescence, and then
stamping the resulting material into the mold. The researchers were
able to create a color similar to the emerald ash borer's green wings
by layering different types of polymer. Eventually they were able to
find the right combination of polymers and number of layers in order
to refract light and create a color similar to the beetle's own
iridescent green. The researchers' findings are scheduled to be
published in the April issue of the Journal of Bionic Engineering.
"Akhlesh's
technique allows us to present males with different visual stimuli,"
said Baker, also a faculty member in the University's Huck Institutes
of the Life Sciences. "We can manipulate more than that, but
right now we are experimentally manipulating the visual decoy."
The researchers had
planned a pilot test in central Pennsylvania, but were unable to
carry it out due to unfavorable regional weather conditions. They
also ran a pilot test in Hungary with a related beetle pest that
bores into oak trees. The pilot in Hungary used two controls -- a
dead EAB and a decoy made of the polymers, but not molded into the
shape of a beetle -- and three types of stamped decoys: one lightly
stamped, another with medium force and the final stamped heavily.
"The preliminary
indication is that these stamped decoys were 40 percent better
than recently dead females in luring and then trapping the males,"
said Lakhtakia.
The stamped decoys are
relatively easy to mass produce, making them both easier to create
and maintain and more successful at trapping males than dead female
borers.
The purpose of the
decoys is to trap the males so that populations of emerald ash borers
can be detected in new locations quickly, paving the way for
efficient use of other control methods, according to the researchers.
"This is a small
dataset, but very encouraging," said Baker, who plans to test
the decoys in the U.S. this summer.
Other members of the
research team were Beverly G. Post, engineering science and mechanics
undergraduate, Penn State; Mahesh S. Narkhede, plastics engineering
graduate student and member of the Center for Advanced Materials, and
Jayant Kumar, professor of physics and applied physics and director
of the Center for Advanced Materials, both at University of
Massachusetts Lowell; and Raul J. Martin-Palma, professor of applied
physics, Universidad Autonomia de Madrid, Spain.
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