Bugs Getting Confused by Asphalt

  • Dragonflies are one of the insects tricked by false light (Photo courtesy of the EPA)

Bugs are getting confused by the
reflections from manmade structures.
Rebecca Williams reports on a new study:

Transcript

Bugs are getting confused by the
reflections from manmade structures.
Rebecca Williams reports on a new study:

If you’ve ever noticed swarms of insects hovering over your car, there’s a
good chance they’re mistaking it for water.


Smooth, dark surfaces like cars and asphalt reflect polarized light. That’s
what bugs see – and that tricks insects such as dragonflies.


Bruce Robertson is an author of the study in the journal Frontiers in Ecology
and the Environment.


“Asphalt actually reflects polarized light more strongly than water and so it
looks more like water than water! And so these organisms are thinking
they’re finding a place to breed and hunt and lay eggs and mate when in fact
they’re finding a place that’s very dangerous.”


Robertson says these bugs swarm over buildings and roads in huge numbers,
and can die of exhaustion.


But he says it might be possible to stop tricking the bugs. Things like
adding white curtains to dark windows or adding a little bit of gravel to
asphalt to make the surfaces reflect less polarized light.


For The Environment Report, I’m Rebecca Williams.

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The Allure of Cicadas

This year, cicadas are re-emerging in many parts of the eastern United States. While not really locusts, they are considered a plague by some people. The Great Lakes Radio Consortium’s Jim Blum goes beyond the backyard to find out there is little to fear:

Transcript

This year, cicadas are re-emerging in many parts of the eastern United States.
While not really locusts, they are considered a plague by some people. The
Great Lakes Radio Consortium’s Jim Blum goes beyond the backyard to find out
there is little to fear:


(sound of cicadas)


Reporter Jim Blum: “I’m Jim Blum with naturalist Dan Best. Seventeen years ago this
month, Magicicada septemdecula and other species of periodic cicadas rose out
of the ground to lay eggs. Then, and now, and likely 17 years from now,
communities will expect a disaster. Dan, is it?”


Naturalist Dan Best: “No, I wouldn’t call it a disaster. Tremendous
natural phenomenon, yes, but disaster, no. Anytime you have large, big buzzy insects
around, people tend to get shook up, whether it’s bumblebees or dragonflies, but
especially when something shows up in prodigious numbers like these cicadas.”


JB: “Now, unlike a large outbreak of gypsy moths, the periodic cicadas don’t
actually eat the leaves.”


DB: “No, that’s right. The damage we are likely to see is the result of
female cicadas laying eggs.”


JB: “How?”


DB: “Well, they have a structure called an ovipositor, and in the end of a
twig they will use this like a little saw to make slits in the twig where they
will lay their eggs inside of that.”


JB: “How will that be apparent to us?”


DB: “Well, the twig will split as a result of several of these little egg laying
gouges in the twig, and from that point the twig may die, or the end of the
branch. And so you’ll notice withered brown leaves at the tips of branches.”


JB: “And that’s what they recognize as ‘flagging?'”


DB: “That’s the term.”


JB: “Now, what size trees are going to be affected?”


DB: “Branches or twigs that are half-inch in diameter or smaller. So on
big, mature trees that’s just the outer growth, no big deal. The trees
that are more vulnerable are the young trees, where literally all the
branches are that size.”


JB: “If this is not a disaster, what is it?”


DB: “I think it’s a tremendous natural phenomenon to experience. It only
occurs like a comet or a blue moon, and perhaps even less frequently than that.
You don’t want to miss it.”


(guitar music)


JB: “Now what’s a good time to see this emergence?”


DB: “Evening, just after dark. You’ll see the holes before the actual
emergence. And then, as they emerge, they’ll be coming up and you’ll see
them all over small trees. The edge of the woods is a good place to see
it.”


JB: “From the pictures I’ve seen, and from what I remember from 17 years ago,
the periodic cicada, bumblebee sized, black, orange eyes and wings. Do
they look like this when they come out of the ground?”


DB: “No, they don’t. What comes out of the ground are the nymphs, the
golden brown color, and no wings at all. Then they make their way up a tree
trunk or out on a branch, and this exoskeleton that they have splits open and
out emerges the adult which is a creamy white color with red eyes and a
couple of big black patches on it.”


JB: “Dan, are these cicadas going to be everywhere?”


DB: “Well, they are not going to be popping out of every square foot of ground in
the area, but there will be kind of a spotty emergence. But very heavy in
some places.”


JB: “If the visual spectacle of the emergence for some reason, doesn’t happen in my yard,
will I have missed out on the experience?”


DB: “No, because it’s almost impossible to escape what comes next.”


(sound up of cicadas)


DB: “The sound is an overwhelming, even annoying, series of buzzes and ticks.”


JB: “How do they make this noise?”


DB: “This loud noise is created by the males to attract the females. The
males vibrate two drum-like membranes to create the sound, which is then
resonated or amplified by a hollow chamber in their body.”


JB: “Not unlike the sound box of a guitar.”


DB: “That’s right.”


(strumming on guitar)


JB: “How long will we hear them?”


DB: “We’ll here this noise during the month of June and be over by about the
Fourth of July.”


JB: “About the same time that the annual or dog days cicadas show up.”


DB: “That’s right, that we’ll here during the hot days of July and August.”


JB: “Now why are those called annual cicadas?”


DB: “Well, unlike the 17-year cicada, which emerges from a single brood in
our area, we have several broods of these annual cicadas which have a much
shorter cycle in the ground. So every year, one way or the other, we have
annual cicadas.”


JB: “Why 17?”


DB: “Jim, I can’t tell you, I don’t know, it’s just one of those great mysteries
of nature.”


JB: “That’s naturalist Dan Best, and I’m Jim Blum, for the Great Lakes Radio
Consortium.”

(cicadas fade out)

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