NARRATOR: It was the
biggest swarm ever seen, 1,800 miles long
and 110 miles wide. JEFFREY LOCKWOOD: It was
phenomenal, one of the largest masses of animal life
that's ever been recorded. NARRATOR: The insect
tornado blocked out the sun for five days. JEFFREY LOCKWOOD: We estimate
that the swarm probably contained about 3 and
1/2 trillion locusts. NARRATOR: Wherever it
touched down, fear, famine, and starvation followed. Locusts are
intimately associated with the wrath of God. NARRATOR: But this was
not some biblical plague. It happened here in America
in the 19th century, and experts fear it
could happen again. Species are shifting
further northward. NARRATOR: Locusts from
Mexico and Central America could swarm across the
US border and sweep through cities,
fields, and farms, devouring and devastating
everything in their wake. [music playing] Super Swarms on
"Mega Disasters." [music playing] The locust is one of the
most dreaded and destructive creatures on earth. The very name evokes a
primordial shudder in humankind that is echoed in
the story of Moses and the eight the
plague of Egypt. Just as the Bible describes
it, a swarm of locusts can wreak a path of destruction
that brings terror, famine, disease, and death. What's terrifying is not the
individual but the numbers, sort of like Alfred
Hitchcock's "Birds." One bird isn't terrifying,
but an entire flock of birds out to get you was horrifying. This perfect swarm can
really bring starvation to an entire country,
to very large areas. And it happened many times
in the historical past. There were millions of people
that died from starvation. NARRATOR: For centuries and
on every habitable continent on Earth, farmers and families
trying to till the land and plant crops have
witnessed the terrors wrought by swarms of locusts. JEFFREY LOCKWOOD: It's almost
as if a firestorm has come through. If you can imagine a raging
fire with everything burnt down to the stubble, the only thing
that's missing is-- is ashes. GREGORY SWORD: I'm sure the fear
that locusts strike in people's hearts ultimately probably
dates back to the fact that plagues of
locusts are mentioned in many of the religious
texts, The Bible, Quran, Torah. [music playing] NARRATOR: In the
"Book Of Exodus," when the Egyptian pharaoh does
not let the Israelites leave for the promised land, God
sends a swarm of locusts to punish him and
plague his lands. Exodus 10:15 states,
"They covered the face of the whole earth,
so the land was darkened. And they did eat
every herb of the land and all the fruit of
the trees, and there remained not any green thing." JEFFREY LOCKWOOD:
The question always comes up, is this plausible? Could this have happened? Is this sort of just a
completely fictive event? When one reads
Exodus, it turns out that the winds they talked
about bringing the locusts, the winds are-- I think they come
on the east winds and are blown out
on the west winds. These sorts of wind patterns
are still the sorts of patterns that we expect to bring
locust to that area, say from the Red Sea
zone over to the Nile. And so when you match up sort
of the description of the winds that preceded the locusts
and where the locusts landed and the sort of
destruction they did, it seems entirely plausible. [music playing] NARRATOR: Entomologists believe
that the species of locust in the biblical eighth
plague was the desert locust. HOJUN SONG: We know that
particular species is the desert locust, because
that's the only species that occurs in Northern Africa. Many times it was found in
Egypt and in nearby areas. GREGORY SWORD: The desert
locust is a specific species of locusts,
Schistocerca gregaria. And it has a huge range. It exists all the way from
West Africa over into India, over in Asia. NARRATOR: At a distance, a swarm
of desert locusts like the ones described in ancient
texts would have looked like a huge, brown dust cloud. Experts believe
the biblical swarm could have infested
thousands of square miles. Usually, a swarm consists
of several million locusts, a more than 10 million locusts. NARRATOR: Even with no
wind, a desert locusts swarm flies up to 7 miles an hour. It seems as if it's
just a weather event, a cloud on the horizon,
sort of a dark cloud. But this cloud, as it
draws closer and closer, looks very different. It begins to shimmer. That's the light reflecting
off the wings of the locusts. And it draws closer and closer. It's at first just seem
like hailstones because they at the leading edge, they just
sort of pelt a few at a time. And then they come
faster and more furious, and you realize that the storm
itself is a swarm of locusts. Once the locusts
get really close, you'll hear their
wings flapping. So it'll make up
a crackling noise. Hundreds of millions of papery
wings beating against the air and beating against the
sides of the insect, that's the sort of thrum,
humming, buzzing, sort of swirling sound. [music playing] NARRATOR: How a swarm
chooses where to land is still a mystery. There is some indication that
they are keying in on certain wavelengths of light, which--
which are an indication of food. So they're looking
for greens and yellows the same way a
traveler on the road would look for a sign that
says McDonald's, this way. Rather than golden
arches, they're looking for green spots. NARRATOR: When a locust
swarm does touchdown, devastation follows. GREGORY SWORD:
Locust, when they eat, they don't have
jaws like humans do. They have what are
called mandibles. And their mandibles move
side to side and front. And they cleave the vegetation
and grind it a little bit before they swallow it. NARRATOR: Even though an
individual desert locust weighs only about half
an ounce, experts calculate that a typical
swarm of 3-inch long insects can inflict awesome destruction. It's often said that a locust
eats its body weight in food a day. We're looking at somewhere
around 200 tons of vegetation, being destroyed by that
swarm on a daily basis wherever it's settled. NARRATOR: And it's not just
crops that locusts devour. HOJUN SONG: They'll
eat any kind of plant. They'll eat trees. they'll eat houses made of wood. [music playing] NARRATOR: By collecting
and studying specimens, scientists hope to gain
a better understanding of this voracious creature. The characteristics
of desert locusts is this long wing extending
beyond the abdomen, and there are some
spots behind the wing. NARRATOR: A locust is, in
fact, a type of grasshopper. All locusts are grasshoppers,
but not all grasshoppers are locusts. ALEXANDRE
LATCHININSKY: There are about 12,000 different
species of grasshoppers, and only about a dozen,
about 12 species of locusts in the world. NARRATOR: Locusts differ
from other grasshoppers in one very key trait. The difference between
a grasshopper and a locust is the way in which locusts
respond to population density or crowding. Normal grasshoppers, if
you put them in a crowd, they're just grasshoppers
that are in a crowd. But locust species respond
to crowded conditions, and their biology, a lot of
things about them change. It's really a "Dr. Jekyll and
Mr. Hyde" transmogrification. When it finds
itself in conditions of crowding or
environmental stress, it undergoes a transformation
we call a phase change. NARRATOR: When this
change happens, the locust looks
radically different. First, the locust changes
color in a process known as aposematism, which
scientists today believe evolved as a biological defense
mechanism designed to ward off predators. STEPHEN SIMPSON: When
they're in a crowd, they selectively pick
out poisonous plants, and they have, therefore,
a gutful of poison, which if a predator comes
along and eats them, causes the predator to
remember not to ever eat that sort of locust again,
and being brightly colored aids in that learning. NARRATOR: In a few
hours, the grasshopper has turned into a locust. But before it can
swarm, the creature has one more major
physiological change to make, which takes a few days. As the insect goes from being a
solitary creature to being one of a crowd or gregarious,
its head actually changes. HOJUN SONG: The shape
of the pronotum, which is a structure on top of
here, is rounder and broader than this. NARRATOR: As the change into
the gregarious phase occurs, locusts band together. They orient towards each
other and form groups. And it's these
active groups that we see as flying swarms of adults. NARRATOR: The benign
grasshopper has now become a deadly scourge. Locusts have plagued
humanity for centuries. Roman author and
naturalist Pliny the Elder in the
first century A.D. wrote about the worst cases
of locust-wrought death and devastation ever known. In Libya, for
example, in Cyrenaica, over two million people died
after one of the desert locust invasions. Died from starvation because the
locusts completely devastated the agricultural areas. As human settlements
and farming expanded across
the continents, so, too, did the severity
of insect plagues. JEFFREY LOCKWOOD: When you
go from a hunter/gatherer to agricultural, concentrate
your food sources, and rely on that food source
for subsistence agriculture, add a locust and
you've got a disaster. NARRATOR: America has not
been immune to the threat of locusts. Huge swarms struck the
pioneer settlers trying to farm the American West. The first Latter Day
Saints, or Mormons, to enter Utah fought to
save their precious crops from a wingless
relative of the locust, known today as a Mormon cricket. DR. SUSAN EASTON
BLACK: The plague had come to the area much like
the great plagues that occurred in Egypt. NARRATOR: For three weeks
insatiable bands of marching insects laid waste
to the Mormons crops. With their lives
threatened by waves upon waves of the
voracious pests, the Mormon settlers fought
and prayed for deliverance from famine, starvation,
and annihilation. Insect swarms have brought
crisis and calamity to almost every
continent on earth. Locusts and other insects
have catastrophically struck Europe, Asia,
Australia, and the Americas at some point in history. DAVID BRANSON:
Locust outbreaks have been recorded on every
continent except Antarctica. NARRATOR: But it is the
African continent, where the extreme climate
conditions are ideal for locust procreation
and population growth, that has been hit the hardest. As the available vegetation
for the insects grows scarcer, locusts crowd together
and compete for the ever diminishing food sources. When the multitude reaches
critical mass and the food disappears, locusts will swarm. Especially vulnerable are the
Arab nations in North Africa. In one outbreak alone
in Algeria in 1867, 250,000 people died
from starvation. When settlers first
arrived in North America, they faced similar ordeals. As the early pioneers spread
into the American West, they were plagued by
huge swarms of insects. It would have
been unprecedented in terms of their experiences. I can't imagine anyone
having seen anything like this, even today. NARRATOR: The first
major encounter that was recorded occurred
in Utah in the 1840s. DR. SUSAN EASTON BLACK:
The Latter Day Saints arrived in the Salt Lake
Valley in July of 1847. In the interim, they had been
planting crops with the idea that there would be literally
thousands that would be coming to join them. NARRATOR: By May 1848,
a few Mormon settlers had plowed and planted nearly
10,000 acres with crops, including wheat, corn,
and assorted vegetables. Then disaster struck. JEFFREY LOCKWOOD:
Out of the hills comes this black
wave of creatures, a blanket across the prairie. And they're headed down
through the drawls, down into the valley. NARRATOR: This black wave
was a swarm of millions of grasshoppers,
soon to be named Mormon Crickets after the
Latter Day Saints they played. STEPHEN SIMPSON: It must have
been pretty demoralizing. They managed to get
their first crop going, and this is a matter of
life and death, of course. Just as it was ripening, over
the hill kind of vast horde of marching Mormon Crickets. And that must have
been pretty depressing. NARRATOR: Unbeknownst to
the settlers, outbreaks occur on average
once every 30 years. When they occur, they can
last for years at a time. If left unchecked,
the mega swarms return every spring in
ever greater numbers, for as many as 20
years in a row. Since they hadn't been
in the region before, what they didn't know is that
the Mormon Crickets hatch in the spring as things warm up. And you often get migratory
bands of Mormon Crickets that move through various
areas, which, unfortunately for the Mormon settlers,
happened to be where they had grown their crops that year. NARRATOR: The Mormon
Cricket, which appears to be a
windless desert locust, isn't actually a locus at all. GREGORY SWORD: Mormon Crickets
are technically katydids. They're long-horn grasshoppers. And locusts are often
in a different group, just the regular grasshoppers
or short-horn grasshoppers. NARRATOR: However,
Mormon crickets behave like desert locusts
in one very significant way. They undergo a dramatic
physical metamorphosis when they get overcrowded. JEFFREY LOCKWOOD: At low
densities at most year up in the mountains, there
are sort of green, little, almost cricket-like
harmless insects, you know, hopping around the meadows. But once the conditions
turn advantageous for them and they become crowded, they
undergo this transformation into this black, dark
brown, coffee brown form. NARRATOR: Once this
physiological change has occurred, they
are ready to swarm. They form groups that can be
millions of individual crickets that are all marching
in the same direction and across the landscape. NARRATOR: On average, a Mormon
Cricket is three times the size of a desert locust. And so can eat
three times as much. The Mormon
Cricket, individuals can be up to three grams. And we know for a fact that a
Mormon Cricket can eat its body weight in food at
least in a single meal. Because a single Mormon Cricket
can cannibalize and consume the entire body of another
similarly-sized Mormon Cricket in one meal. If an individual from a
band, a swarm gets injured, they'll eat that individual. Other individuals jump on them. They're eat each other. GREGORY SWORD: Turns out
it's this cannibalism that's one of the driving mechanisms
of movement within the band. The crickets need to
keep moving in order to avoid being attacked by
the crickets approaching from behind. So this whole process is
basically a forced march driven by cannibalism. JEFFREY LOCKWOOD:
The terrifying thing is that there is basically
no way to stop them. They're sort of like
this living wave rolling across the ground
of these black insects. HOJUN SONG: They're
omnivorous, meaning that they eat everything. They eat plants. They will eat carcasses. JEFFREY LOCKWOOD: There's even
reports of them biting humans and drawing blood. NARRATOR: These early Mormon
pioneers faced many tests, but the onslaught of
the marching crickets was the most difficult. The pioneers who had buried
children along the trail, who had endured cholera,
all kinds of problems, they'd finally landed in a place
where their leader, Brigham Young, who was viewed as the
American Moses, was saying this is the right place. Only to find, it
appeared, perhaps a plague had come to the area much like
the great plagues in Egypt. For sure, many would have
viewed it as a test of faith. NARRATOR: For three long
weeks, the insatiable crickets poured into the
Salt Lake Valley. The crickets were directly
taking foods from their mouth, potentially wiping out the
food that they're trying to grow for the coming year. The question was
how to stop them. They came up with several ideas. Each one of them failed. NARRATOR: The Mormons tried
to bury, burn, and drown the crickets. But nothing could
deter the onslaught. It just seemed like everything
they tried didn't work. The result was they prayed
to their father in heaven and asked for relief. NARRATOR: According
to Mormon accounts, after three weeks of constant
plague a flock of seagulls entered the valley and began to
consume the hordes of swarming crickets. DR. SUSAN EASTON BLACK:
The seagulls kept coming, kept coming. Some accounts will have them
flying all the way to the Great Salt Lake, dropping the
crickets into the lake, and then coming
back to get more. NARRATOR: For three weeks the
seagulls feasted on crickets. DR. SUSAN EASTON
BLACK: And by the end, all the crickets were
gone from the valley. For members of the Church of
Jesus Christ of Latter day Saints, this was a
miracle for them. At least, viewed by
the farmers as such. NARRATOR: According
to entomologists, there may be a natural
explanation for what happened that year in Salt Lake Valley. GREGORY SWORD: That
gulls showed up and fed on Mormon Crickets that
were in the early settlers' crops is probably
almost certain. But whether the gulls
eradicated the crickets alone or the crickets moved along
and should share credit with the gulls themselves
is up for debate. JEFFREY LOCKWOOD: It may have
been the case that the seagulls were gorging themselves
on these crickets. And certainly may
have made enough of a dent in the
population, at least locally, to have
really made an impact in terms of keeping the
Mormons from utter disaster. NARRATOR: Science aside,
for the Latter Day Saints there is no doubt it was a
case of divine intervention. DR. SUSAN EASTON BLACK: We call
it the Miracle of the Gulls. So as a result,
Latter Day Saints continued to live
in the valleys. NARRATOR: But the Mormon
Cricket swarm of 1848 was just the lull
before the storm. Greater horrors were about to
beset American pioneers trying to settle and farm the
lands across the west. When several years
of wet weather were followed by severe
drought, the perfect ecological conditions were set by the 1870s
for a super swarm of a North America-bred insect. It would come to be known in
infamy as the Rocky Mountain Locust. JEFFREY LOCKWOOD: If the
Mormon Cricket was bad, the Rocky Mountain Locust
is absolute disaster. They can fly, and so their
capacity to move quickly and to move from field to field
is even worse than the Mormon Cricket. NARRATOR: This time,
tens of thousands would face famine
and starvation. HOJUN SONG: People were really
scared of Rocky Mountain Locusts. NARRATOR: Farmers
quickly realized that a swarm of ravenous
Rocky Mountain Locusts could wipe out a year's worth
of crops in a few hours. What's more, no one could
predict when or where a swarm would strike. The unfortunate might see
the locusts arriving this year, next year, maybe only
a two year break, and then they're back again. Other places, it
might be six, seven, eight years before another
locust swarm arrives. NARRATOR: Making matters
worse, swarms of Rocky Mountain Locusts were massive. JEFFREY LOCKWOOD: These insects
arrive by the millions, tens of millions,
hundreds of millions. NARRATOR: With each
unconstrained outbreak, the locust swarms
caused ever more damage. Then in 1875, pioneers
on the American frontier faced the largest
swarm ever seen. JEFFREY LOCKWOOD:
It's 1,800 miles long. The sun itself becomes blocked--
biological eclipse of the sun. Something that had never been
experienced by these people and has never been experienced
on the North American continent. NARRATOR: In 1875 in
the Rocky Mountains, the sun was blocked
for five days by the largest swarm
ever seen on earth. So it was phenomenal. One of the largest
masses of animal life that's ever been recorded. NARRATOR: It came to be known
as Albert's Swarm, named after a Nebraska physician
who measured the onslaught. Albert Child turned out to be
not very interested in locusts at all. But what he was really in
love with was meteorology. He was a weather watcher, an
early climatologist, a reporter of weather conditions. NARRATOR: Child first
sighted the swarm in Nebraska on June 15, 1875. JEFFREY LOCKWOOD:
Child, of course, sees a swarm as sort of a
climatic or weather event. So what he does is he measures,
as accurately as he can, the flight speed of the
locusts that are passing over. And he does this based
on both their flight speed and his measurements
of wind speed. NARRATOR: Child calculated
that the swarm front was moving at 15 miles an hour. JEFFREY LOCKWOOD: But
how wide is the front? That's what he can't tell. So he telegraphs east and west
to find where the swarm drops off. And so that gives him a whiff. So now he knows how wide the
front is of the locust swarm, and he knows how fast
it's passing over. NARRATOR: Child knew that if he
waited to see how long it took for the swarm to pass overhead,
he could measure its length. He waited five days. JEFFREY LOCKWOOD: And
when he does the numbers, the swarm is at
least 100 miles wide. And then it's 1,800 miles long. NARRATOR: Using a telescope
and a measured distant point on a hill, Doctor Child
calculated the height of the swarm as a
mile and a half high. Entomologists today have come
up with their own estimate for the total number of insects
in the 1875 super swarm. HOJUN SONG: The biggest swarm
of the Rocky Mountain Locusts contained about 3.5
trillion individuals. NARRATOR: Albert's Swarm
stretched across the length of the Western United
States, in total, an area encompassing
198,000 square miles. JEFFREY LOCKWOOD: It was
pouring out of Texas. And it was riding a very
particular weather system that provides a stable conveyor
belt of air passing northward over Kansas, Nebraska,
and up into the Dakotas. NARRATOR: For American farmers
on the Western frontier trying to plant their crops
in June, 1875, the site of the largest swarm
in human history would have been terrifying. The locusts are
coming over the horizon, a brownish, yellowish cloud
descending on this land. And then you begin
to hear the swarm. The farmers figure out pretty
quickly, this is not a storm. At least it's not a weather
storm, it's a biological storm. And then blankets
of locusts come. They're coming everywhere,
crawling on you, in your hair, into your clothes, through
everything and everywhere. NARRATOR: Making the situation
worse for the settlers, no one knew where this ravenous
super swarm would touch down. It makes it seem
somehow magical or evil-- one district can be
absolutely decimated. A district a short distance away
may suffer almost no damage. Sort of like a twister. NARRATOR: Some eyewitnesses
claim that the swarm feasted on wood, fabric, and flesh. They'll eat anything
with moisture. It's been reported they'll even
chew on the handles of tools, almost polishing
them to a gleam. And they're doing that
probably to extract the salts left behind after perspiration. NARRATOR: But it was
the settlers crops that provided the locusts
with the best source of food. By some estimates,
300,000 acres of farmland had been devastated. In 1875, half of all Western
agricultural production was lost to the locusts. Thousands of settlers
on the American frontier now faced famine. JEFFREY LOCKWOOD:
They're looking at their food for the
coming year disappearing. They're not facing bankruptcy. They're facing
death by starvation. NARRATOR: Stationed out
west, US army general EOC Ord was so shocked by the suffering
that in October, 1875, he petitioned the government
back east for aid. 100,000 settlers were at risk. And so what Ord did was to
convince the government first of all, to release US military
property in terms of clothing and shoes to protect the
people from the oncoming cold. NARRATOR: Thanks to
General Ord's pleas, for the first time
in American history, the US government sent the
army on a relief mission. In that winter, about 2
million food rations were distributed throughout
the locust-impacted areas. NARRATOR: Despite the best
efforts by General Ord and the army, historians
estimate that several hundred Americans may have died of
starvation in the 1875 plague. No official numbers
were ever reported. While the Locust swarm of 1875
would be the worst in terms of crops destroyed
and lives lost, it would not be the last
on the American frontier. Somewhere in the
west, the locust was probably doing damage
every three to five years with major outbreaks probably
occurring every six to eight years. NARRATOR: For farms to flourish
and the west to be settled, the locusts had
to be controlled. In 1887, Congress created the
United States Entomological Commission and
appointed scientist Charles Valentine Riley to
solve the locust problem. HOJUN SONG: CV Riley
was the first person to systematically investigate
the biology of the locust to figure out how
to control them. NARRATOR: Riley was the first
to detail the three life stages of the locust-- egg, nymph, and adult.
By tracking the locust across the country, he also
discovered the creatures' breeding ground. Riley found that the locust
originated from fertile river valleys high up in
the Rocky Mountains. When the conditions turned
right for its populations to reach high numbers, high
densities, which would trigger the transformation into
the migratory phase, it would come pouring out of
those mountain valleys down across the prairies
in search of food. NARRATOR: On the way, the
locusts seed the ground with the next generation. HOJUN SONG: They'll
mate and they lay egg. The cycle continues. If you multiply
that by millions, then you end up with
a lot of locusts. NARRATOR: The way
to stop the locusts, Riley concluded, was to
destroy their egg pods. JEFFREY LOCKWOOD: The time
to attack the Rocky Mountain Locust is before it
emerges from the ground. They understand that it's
the egg the stage that's the vulnerable stage. NARRATOR: Riley's findings
spurred a massive effort by farmers to stop the
locust eggs from hatching. Slews of ingenious machines
that sucked, burnt, and poisoned were dispatched west to try to
eradicate the pest that plagued the frontier farmers. They are clever, but
I'm not really sure if they really worked. NARRATOR: Then suddenly, the
Rocky Mountain Locust vanished. Within a period of about 10,
15 years, the most phenomenally abundant insect in the
history of North America went from breathtaking
numbers to extinction. Its death was almost
instantaneous. The last known sighting of
the Rocky Mountain Locust was in 1902. A small swarm was seen flying
through Manitoba, Canada. NARRATOR: It would be the
last locust swarm ever sighted in North America. Some attributed the
demise of the locust to the government's
eradication program. But many experts today
believe that the real reason was deceptively simple. The farmers who
moved into the valley crushed the locust eggs when
they plowed their fields. JEFFREY LOCKWOOD: At the same
time, livestock are moving in. So they're grazing in
the stream side areas. They're trampling this habitat
of the Rocky Mountain Locust. NARRATOR: The American pioneers
who had witnessed the biggest swarm ever seen had their
revenge on the locust. They survived and thrived. But locust swarms of
catastrophic proportions still occur all over the world. GREGORY SWORD: The people
who are most affected by these swarms are often the
subsistence farmers and people who are reliant on their local
food production for the food that they need to survive. NARRATOR: In order to
save precious lives, scientists today are conducting
a host of high tech experiments that may unlock the mystery
of why locusts swarm. This research could be critical. Some experts believe that if
the climatic and ecological conditions are
right, we could be on the verge of another
catastrophic plague of locusts in the United States. Experts estimate that 20%
of the Earth's landmass is within striking
range of locusts. If the worst happens and a
swarm strikes across continents, one in 10 of the
world's population could face famine
and even death. If you imagine a
large swarm sweeping through underdeveloped nations
which rely on agriculture, people will starve. NARRATOR: The most
destructive species is the desert locust, the
locust of the biblical plague. ALEXANDRE LATCHININSKY:
When there is an outbreak, it can cover about 20%
of the Earth's dry land in more than 60 countries. NARRATOR: When a
swarm does strike, local governments
and aid organizations may find their
methods used to fight the infestation inadequate. GREGORY SWORD: Typically,
pesticides are used. Go out with airplanes and
spray huge swaths of area to knock the locust back. It's not a good solution,
because locusts will eventually develop resistance
to the pesticides. DAVID BRANSON: There's also
high costs, both economically and also possibly
environmentally, of using such approaches. Scientists NARRATOR: Are trying to fight
locust outbreaks by studying their biological
process of phase change. Once we understand
those factors, we can potentially
manipulate them to reduce the
severity of outbreaks or possibly prevent them at all. The process of phase change is
really central to what a locust is and how swarms form. The most important
trait of all the traits that can change when
locusts become crowded is their behavior. JEFFREY LOCKWOOD: What is
it that signals the locust to transform itself? What it comes down
to, apparently, is two key features. One of those, the earliest
one discovered, was odor. The grasshoppers,
when they defecate, their feces produces an odor
that basically signals them that they're becoming crowded. When your habitat starts
smelling like a sewer, you know there's a lot of you. The other thing that
they probably [inaudible] on, and this is more
recent research, is actually tactile or touch. STEPHEN SIMPSON: Well,
the process we found was induced by
touching the back legs. And there are special
hairs on the back legs that induce this effect. And it's become known as
the g-spot of the locusts. G for gregarization,
in this case. NARRATOR: Some experts reason
that this stimulation sets off a chemical and physiological
chain reaction inside the body. Scientists have discovered
that weather directly impacts the phase change
process and population density of the desert locust. You've got to have rainfall
in order to have plant growth for the locusts to feed on. And you have to have moisture
in the soil for their eggs to develop. Given a number of generations of
good breeding conditions caused by good rain and suitable
vegetation and moisture for egg development,
the populations can build up and boom. NARRATOR: On average, swarms
occur every seven to 10 years, but it depends on climate. If a few years of rainfall
are followed by drought, the gregarious locusts
get anxious to migrate. As conditions become drier
the area of suitable habitat for locusts contracts. So the locusts, they're going
to become crowded and ultimately come in contact with each other. And it's this contact among
the individual locusts that causes them to shift
from the non-migratory to the migratory phase. So this changes their behavior. They start to form large mobile
groups that we see as swarms. And these swarms are migratory. They then take off from the
habitat where they started and end up in new places. NARRATOR: Today, even though the
infamous Rocky Mountain Locust is believed to be extinct,
farmers face a new danger from Mormon crickets, which
have returned in huge numbers. In the Western US, we've
been going through a big Mormon Cricket outbreak over
the last several years. Typically, Utah, Nevada, Idaho
tend to be the hardest hit. The latest upsurge peaked in
about 2004, and at that point there were major outbreaks in a
majority of the Western states. In that year, about $20
million was allocated by the federal government alone
for Mormon Cricket control. NARRATOR: In a field
study in Nevada, Greg Sword and Steve Simpson
head a team of scientists who use state of the art technology
to try and track the migration patterns of Mormon Crickets. We need to know
where they're going and what determines the
direction that these groups might travel over time. And to do that, we use
small radio transmitters. And we can actually glue
them to individual insects, much like you might put
a radio collar on a bear and track its movement over
time using radio-telemetry. And if you know where the
source and the destination is, you can predict what
areas might repeatedly be sources of Locust outbreaks. And where those locusts
are then going to go. And we can use that information
to improve their management. What we're doing now is
we're going to glue a radio transmitter on it. And shortly after putting
the transmitter on it, we're going to release
it into the band. So we put a little
drop of hot glue. The radio on its back. Orient the antenna so
it's down the body. We're good to go. Navigation. Things are happening. NARRATOR: Greg Sword believes
that genetics may hold the key to stopping the global
swarming of the locust. GREGORY SWORD: We're
able to look at its DNA. And we can use this information
to identify the specific genes that are turned on that
result in the expression of migratory behavior. Ultimately, it may be possible
to manipulate the expression of this behavior at
the genetic level. NARRATOR: In other words,
stop them swarming. But control techniques
remain in their infancy, and it may take many years
before this research yields practical results. Meanwhile, some scientists warn
there is a more immediate area of concern. They believe that global
warming is increasing locust populations worldwide,
and it is also changing their migration patterns. They say it could drive swarms
of central American locusts into North America. There's even outbreaks going
on right now in the Yucatan Peninsula area of Mexico. NARRATOR: Some experts predict
that with global warming changing climate patterns,
locust swarms could once again sweep through the
Western United States. Scientists fear locust
populations could explode in the near future. If so every continent on earth
would be in the danger zone. Some experts believe this
could herald the return of locust swarms to
the United States in the form of the so-called
Central American Locust. We do have some indication
that species distributions in North America are shifting. In particular, species are
shifting further northward. NARRATOR: A recent study of
the geographic distribution of grasshoppers points
to an ominous trend. Dan Johnson, who's a
researcher in Canada, has done more recent grasshopper
surveys and compared them back to surveys of some
decades ago and has found that a number of species
are being found further north in Canada than they used to be. NARRATOR: With the right
climatic conditions, locust numbers build. When this happens, the insect
senses increased competition for food supplies. Then a tipping point is reached,
and each insect quickly changes its shape, color, and behavior. Once completed, the locusts form
one giant swarm and take off. If the size of
the swarm is big, if it contains several
million individuals, then of course people
will freak out. NARRATOR: Entomologists
fear that in this worst case scenario, a swarm of
Central American Locusts could head north in
search of food and water. JEFFREY LOCKWOOD: Let's say
this Locust outbreak moves up from Mexico into the
southwestern United States. Locust swarms
moving into Houston, moving into Phoenix and Tucson. San Diego, Los Angeles. It would be frightening. It would be incomprehensible. It would be terrifying. NARRATOR: The sky darkens as
the insect tornado closes in on the city. ALEXANDRE LATCHININSKY:
If they reach big cities, they can really create havoc. They're ubiquitous,
they go everywhere, they fly, they hit
you in your face. They hit you in your body. JEFFREY LOCKWOOD: Crawling
into your clothes, under your clothes, into
window screens, piling up against your house. So many locusts
landed on the roads, and cars then drove
over the locusts and caused slick
driving conditions. You might get some
more traffic accidents. NARRATOR: Propelled
by winds, the locusts could cover a 100 miles a day,
landing to feed, breed, and lay eggs. When the eggs hatch
and locusts grow, this perfect mega swarm
could have billions of windless nymphs
charging and chomping through field and farm. People in US,
governments, and cities, are not equipped to deal with
locusts because it's not real-- it's unlikely. And they probably don't
know how to deal with it. NARRATOR: Emergency
services, desperate to avert total catastrophe, may propose
deploying airplanes loaded with pesticides to spray
the swarms of locusts. JEFFREY LOCKWOOD: We have all
sorts of bureaucratic and sound environmental reasons why large
scale spraying can't simply be done on an emergency basis. It requires permissions. It requires environmental
justification. It requires a great
deal of documentation. We probably don't
have enough aircraft available for this, either,
in terms of dealing with this. HOJUN SONG: When locusts
are already airborne, then chemical pesticide
will not be that effective. DAVID BRANSON: The other
problem with chemical control is that you may not have
a long-term control. You knock the populations
down, but some research indicates that you may actually
make it a little bit more likely you'd have an
outbreak in the future. NARRATOR: Public
anxiety would grow. JEFFREY LOCKWOOD: This familiar
sense of fear, loss of control, panic, blame-- what's causing this? Who's in charge? Why isn't something being done? NARRATOR: Experts estimate
that the nation's 200 million and more acres of crops
could be decimated. Our supply of important
crops would be basically gone in a matter of a few days. NARRATOR: Billions of dollars
would be lost in agriculture alone, and thousands
of ranchers and farmers could lose their livelihoods. Food shortages and
famine could follow. JEFFREY LOCKWOOD: The impact
in terms of its duration could be one to three years. Will the locust
swarm cause hunger? Not for us. Will the locust swarm
cause hunger elsewhere, as we have the money to buy
food that may be limited for other people? That becomes much more likely. So my sense is that we
would transfer the hunger to poor countries. NARRATOR: This scenario is
still just hypothetical. For centuries,
millions of people the world over have
witnessed, endured, and suffered the devastation and
death carried by locust swarms. But scientists know
that they must find ways to stop the next super swarm. We can read about
outbreaks in "The Bible." And obviously, the fact that
we haven't solved it yet indicates it's a
really complex problem. GREGORY SWORD: We need to
have a better understanding of the basic
ecological processes that are occurring before
outbreaks so we can prevent an outbreak from occurring
in the first place.
