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Plastic bee hives create buzz
A new study reveals that some bees use
bits of plastic bags and plastic building
materials to construct their nests. The
discovery shows bees’ resourcefulness and
flexibility in adapting to a human-dominated
world, says Scott MacIvor, a doctoral student
at York University and graduate of University of
Guelph, both in Ontario. Although researchers
have shown adverse impacts of these
materials on various species and ecosystems,
few scientists have observed insects adapting
to a plastic-rich environment.
Determining that bees are using plastics in
place of natural materials was accomplished
by Andrew Moore, supervisor of analytical
microscopy at Laboratory Services. He
analyzed grey “goo” discovered in the nests of
one kind of bee, Megachile campanulae, which
uses plant resins to build its nests. A scanning
electron microscope identified the polymers.
The bees also occasionally replace plant resins
with polyurethane-based exterior building
sealant, such as caulking, in their brood cells—
created in a nest to rear larva.
Researchers also discovered that another
kind of bee, Megachile rotundata, uses pieces
of polyethylene-based plastic bags to
construct brood cells. The glossy plastic
replaced almost 25% of the cut leaves
normally used to build each cell. Markings
show that the bees chew plastic differently
than leaves, suggesting intentional plastic
collection. For more information: Scott
MacIvor, ,
.
ADVANCED MATERIALS & PROCESSES • JUNE 2014 63
Chickens see new state of matter
The unusual arrangement of cells in a chicken’s eye constitutes the first
known biological occurrence of a potentially new state of matter known as
“disordered hyperuniformity,” according to researchers from Princeton
University, N.J., and Washington University, St. Louis. Research in the past
decade has shown that disordered hyperuniform materials have unique
properties when it comes to transmitting
and controlling light waves. These
findings add a new dimension called
multi-hyperuniformity, meaning that the
elements that make up the arrangement
are themselves hyperuniform. While
individual cones of the same type
appear to be unconnected, they are
actually subtly linked by exclusion
regions, which are used to self-organize
patterns. Multi-hyperuniformity is crucial
for the avian system to evenly sample
incoming light, say researchers. It is
speculated that this behavior could
provide a basis for developing materials
that can self-assemble into a disordered
hyperuniform state. ,
.
Sapwood filters bacteria from contaminated water
Need a simple solution to make drinking
water? Simply break a branch off a pine tree,
peel away the bark, and slowly pour water
through it. The improvised filter should trap any
bacteria, producing fresh, uncontaminated
water. A team at Massachusetts Institute of
Technology, Cambridge, discovered that this
low-tech filtration system can produce up to
four liters of drinking water per day—enough
to quench the thirst of a typical person.
Researchers demonstrate that a small piece
of sapwood can filter out more than 99% of
the bacteria E. coli from water. They say the
size of the pores in sapwood—which
contains xylem tissue evolved to transport
sap up the length of a tree—also allows
water through while blocking most types of
bacteria.
To study sapwood’s water-filtering potential, branches of white pine
were collected and the outer bark was stripped off. Small sections of
sapwood measuring about 1 x 1 in. were cut and mounted in plastic tubing,
sealed with epoxy, and secured with clamps. Before experimenting with
contaminated water, water mixed with red ink particles ranging from 70 to
500 nm in size was used. After the liquid passed through, researchers sliced
the sapwood in half lengthwise and observed that much of the red dye was
contained within the very top layers of the wood, while the filtrate, or filtered
water, was clear. .
Bees are now incorporating plastics into nest
construction. Courtesy of Albert Herring/Wikimedia
Commons.
Diagram depicts the spatial
distribution of the five types of light-
sensitive cells known as cones in
chicken retinas. Courtesy of Joseph
Corbo and Timothy Lau,
Washington University.
A false-color electron
microscope image showing
E. coli bacteria (green) trapped
over xylem pit membranes (red
and blue) in the sapwood after
filtration.