68 Science & technology The EconomistFebruary 1st 2020
2 The contract called for Dr Lieber to pub-
lish “high-level articles” in renowned jour-
nals and to host international conferences
“in the name of Wuhan University of Tech-
nology”, and to guide young scholars and
doctoral students, helping them publish in
respected international journals. In Janu-
ary 2013, the affidavit says, he signed a five-
year contract formalising Harvard’s co-
operation in the joint lab, and obliging Har-
vard to host researchers from wutfor two
months a year.
According to the fbi, officials from Har-
vard said Dr Lieber did not have the author-
ity to sign such a contract. Those officials
also said they eventually became aware of
the joint laboratory, and that Dr Lieber was
its director, in about early 2015. When con-
fronted, Dr Lieber told Harvard officials
that wut“was using Harvard’s name and
logo without his knowledge and consent”,
the affidavit says.
In 2018, the affidavit says, Dr Lieber told
investigators from the defence department
that he was never asked to participate in
the Thousand Talents programme, but that
he “wasn’t sure” how China might describe
him. The fbialso says he caused Harvard to
report falsely to the nihthat he was not a
participant in the recruitment programme
(the nihrequires disclosure of such for-
eign payments to grant applicants). Mean-
while, the email traffic quoted in the fbiaf-
fidavit describes the payments to Dr Lieber
going into a Chinese bank account set up
on his behalf and, on occasions he visited
Wuhan, given to him in cash.
In return for its association with Dr
Lieber, Wuhan University of Technology
may have burnished its reputation in
nanoscience, and developed some young
scholars in the field. The lab itself was
meant to focus on “nanowire-based lithi-
um ion batteries” for electric cars, per the
contract Dr Lieber allegedly signed. In re-
cent years Dr Lieber’s research has focused
on “neural lace” technology, the still-na-
scent field that Mr Musk is looking to de-
velop. Mr Musk’s own paper on the topic
cites Dr Lieber as well as Chinese research-
ers who worked in his lab at Harvard.
It is not clear how much special insight
Chinese researchers gained that they
would not otherwise have had. Leading sci-
entists routinely note that in such high-
level research international collaboration
is increasingly common, and can happen
organically. Most research is published
openly for all to see. It is not certain that
Chinese largesse was required to pry open
the wonders of a top laboratory at the
world’s most prestigious university. But
the Trump administration says that was
precisely the goal of the Thousand Talents
programme, and that university adminis-
trators and scientists have been asleep to
the threat such recruitment programmes
pose. If so, no longer. 7A
butterfly’s wings can have many
jobs besides keeping the insect aloft.
They may be called on to attract mates, to
warn potential predators to stay away, to
mimic other animals or even to provide
camouflage. All of these roles, though, de-
pend on their colouration—which is un-
changing. This plays into the idea that but-
terfly wings are dead tissue, like a bird’s
feathers or a mammal’s hair. In fact, that is
not true. For example, in some species
males’ wings harbour special cells that re-
lease pheromones which attract females.
Nanfang Yu, a physicist at Columbia
University, in New York, has been looking
into the matter. One of his interests is the
optical properties of biological materials.
That has led him to study butterfly wings in
more detail. And, in collaboration with Na-
omi Pierce, a butterfly specialist at Harvard
University, he has now shown, in a paper
published this week in Nature Communica-
tions, that butterfly wings are, indeed, very
much alive.
Initially, Dr Yu and Dr Pierce wanted to
know how the insects keep their body tem-
peratures up without their wings overheat-
ing. Unlike birds and mammals, butterflies
do not generate enough internal heat to
run their metabolisms at full pelt. Instead,
they rely on outside heat sources—usually
the sun—to bring their bodies up to speed.
But their wings, being thin protein mem-
branes, have a limited thermal capacity.
Those wings can therefore overheat quick-ly if the insects bask too long in sunlight,
or, conversely, can cool down too rapidly if
they are flying through cold air.
In their experiments, the two research-
ers used a laser to heat up spots on the
wings of dozens of butterfly species, in-
cluding the painted lady and the hickory
hairstreak (pictured). When the tempera-
ture of the area under the laser reached
40°C or so, the insects responded within
seconds by doing things that stopped their
wings heating up further. These actions in-
cluded a butterfly turning around to min-
imise its profile to the laser, flapping its
wings or simply walking away.
Butterflies engaged in all of these heat-
minimising activities even when the re-
searchers blindfolded them. That suggest-
ed the relevant sensors were on the wings
themselves. Dr Yu and Dr Pierce therefore
searched those wings for likely looking
sensory cells. They found some, in the
form of neurons that resembled heat detec-
tors known from other insects. They also
uncovered disc-shaped cells that appeared,
again by resemblance, to be pressure-sen-
sitive neurons. They speculate that these
are there to detect deformation of the
wing—information an insect could use to
control its flight pattern.
The third discovery Dr Yu and Dr Pierce
made to contradict the “dead wing” hy-
pothesis was that some butterfly wings
have a heartbeat. Anyone who has looked
closely at a butterfly will know that its
wings have veins. These carry a bloodlike
fluid called haemolymph. For a long time,
entomologists thought the only role of the
veins was, by being pumped full of haemo-
lymph, to inflate the wings to full stretch
after a butterfly emerged from its chrysalis.
More recently, it was discovered that hae-
molymph continues to flow through the
veins throughout the insect’s life. Dr Yu
and Dr Pierce have now found that in male
hairstreaks the haemolymph shows a pulse
of several dozen beats per minute. The
source of this pulse appears to be the scent
pad, a dark spot on the wings that produces
the female-attracting pheromones. Appar-
ently, this “wing heart” acts as a pump that
helps propel haemolymph through the
scent pad.
In all their experiments simulating dif-
ferent environmental conditions, Dr Yu
and Dr Pierce consistently found that, re-
gardless of pigmentation, the living areas
of a butterfly’s wings—which cluster
around the veins and are presumably nur-
tured by them—were always cooler, by up
to 10-15°C, than the lifeless membranes be-
tween the veins. The cause, they discov-
ered, was that different parts of the wing
are covered by different sorts of scales. In
particular, scales over the scent pads are
penetrated by tubes. This improves their
ability to radiate heat away and helps keep
the living parts of a butterfly’s wing alive. 7Far from being dead tissue, butterfly
wings are sophisticated living organsEntomologyMore than meets
the eye
Any wing that had a heart