Hunger on the Wing (Part 2 of 3)



(An expanded version of a story from The Book of Deadly Animals. Go to the beginning of this story.)

The most vivid firsthand account of swarm behavior is surely that of Laura Ingalls Wilder, the children's writer who chronicled the life of her family on the American frontier. By 1874 Wilder's restless father had moved the family to a homestead near Walnut Grove, Minnesota. Wilder vividly paints the heat of that summer: The edge of the prairie "seemed to crawl like a snake" with heat shimmer, and the pine boards of buildings dripped their viscous sweat. The family's wheat crop, which promised to yield generously, was head-high. Then a cloud dimmed the day, moving in without wind. Its individual particles glittered. The falling insects sounded like a hailstorm, and this sound was succeeded by the multitudes chewing (like the working of thousands of scissor blades, some witnesses said). Prairie grasses and wheat and oat crops vanished; beets, beans, potatoes, carrots, and corn were razed; willow and plum trees were shorn. (Although the Ingalls family didn't grow these crops, others noticed the insects preferred to start with tobacco and onions when these were available.) "Not a green thing was in sight anywhere" after a few days, Wilder concludes, echoing the Book of Exodus.

Only the family's chickens benefited, snapping up the windfall of easy prey. (Some writers of the period noted that the chickens took on the flavor of grasshoppers, and that they and their eggs became inedible. Others wrote that the grasshoppers themselves were edible, though the Ingalls family does not seem to have taken an interest in this option.) The family fell on hard times, and at night they could hardly sleep for the sensation of crawling on their skin. On Sunday they arrived at church with their best clothes crawling with grasshoppers and stained with their brown spittle. The meager creek thickened with scum, and the land twitched with dust devils. The cow's milk went bitter and nearly dried up.

Today's American infestations are minor compared with swarms like those, but they still devastate wide areas from the Pacific Northwest to the Great Plains. About 2 million acres of Colorado have been eligible for treatment against grasshoppers in a single year, and it is not uncommon for several counties at a time to be affected by infestations. In an ordinary season, grasshoppers eat about 20 percent of the fodder on rangeland; in areas of infestation, the percentage can increase to 100, affecting millions of acres at $5 to $10 per acre. On cropland, the devastation is even greater.

Although the Rocky Mountain locust, the species that wreaked havoc here in the 19th century, does seem to have disappeared, its ecological niche may be only temporarily vacant.


At rest, the red-legged grasshopper, a close cousin of the Rocky Mountain locust, looks vaguely mechanical. Two immense eyes take up the sides of its head. Roughly between these are three smaller eyes and a pair of short antennae. The hard, yellow-green underside of its thorax is marked with deep indentations that resemble smiley faces doubled and distorted in mirrors. The abdomen is segmented. The rear of it ends in four blunt appendages closed together like pinching fingers. When the insect takes flight, its vitality is revealed. The camouflaged forewings open to show the vivid hind wings, which flutter loudly and too fast to be seen distinctly. The specialized hind leg is a marvel of complexity. It possesses sensory equipment as well as a comblike projection used by the male to coax music from his wings, and its muscles are powerful enough to accomplish some of the most impressive leaps, proportionally speaking, in the animal kingdom.

Rocky Mountain locusts laying eggs in topsoil

Much of the grasshopper's insides are taken up by reproductive equipment. The female's ovaries produce rows and rows of eggs, which are attached by stemlike parts to each other. The effect is something like an orderly bunch of grapes, lined up mostly in neat rows, and glistening with moisture. However, the naked eye is impressed mainly by the fat black strand of digestive tract. Narrower in spots and girdled with knotty, fibrous projections near the middle, it is essentially a tube. The dark color is that of chewed vegetation. At any given time, a substantial proportion of the grasshopper's body weight is its unconverted food. When a grasshopper is eaten by a mantis, the mantis typically eats around this unattractive vegetation. It is left holding the digestive tract, which resembles the stick at the center of a corn dog.

That summer in Oklahoma, I caught some grasshoppers in jars and fed them on weeds and grasses. They ate avidly, leaving nothing of my offerings. Their mouths had toothed jaws with multiple points of articulation, a complex arrangement that appeared to constitute two or three mouths working at once. In fact, this equipment allowed them to chew both vertically and horizontally. Typically, they chewed along a blade of grass, creeping up the blade several inches before going deeper. Or they chewed a hole through the blade, then expanded the hole until the blade was cut in two and it collapsed.

The jars didn't suit them: They were heavy, humid creatures, and in a day or two the glass was fogged with condensation, the bottom of the jar laden with their conical black feces and their spit. They died off quickly, even when placed in more commodious accommodations. I tossed a grasshopper into the web of a black widow spider, assuming the spider would dispatch it quickly. Instead, the grasshopper's energetic struggles wrenched it loose from the web, though at the cost of a hind leg. I repeated this experiment with a different individual. This time the grasshopper's leaps freed it easily, and further leaping knocked the spider from its web. The spider lay on its back, kicking frantically, as the grasshopper chewed its front leg.

It's such hunger that drives a locust swarm. A single desert locust can eat its own weight in a day. Multiplied by a billion, this hunger may be the most demanding our planet has known. The mechanisms behind the behavioral change from solitary grasshopper to swarming locust are not well understood. In the laboratory, scientists have been able to provoke grasshoppers into a phase shift by pelting them with wads of paper for hours on end. This result suggests that the jostling the grasshoppers experience in a group prompts the phase shift. Stephen Simpson of the University of Oxford has located the hardwiring for this mechanism more precisely on the insects' hind legs. A spot there (which Simpson calls "the G-spot—G for gregarization") is the trigger that somehow provokes morphological changes. (Other research, now largely disproved, pointed toward pheromones found in the feces, most likely produced by gut-dwelling bacteria, as the stimulus to change.) It may be that multiple cues are involved, and perhaps different locust species use different cues.


Population explosions occur in various animal species, from rabbits to mayflies. Vast migrations occur in creatures as diverse as monarch butterflies and wildebeests. But the phase shift and swarming of grasshoppers appears to be unique. It may provide a way to survive and reproduce when food supplies dwindle. In Africa, the desert locust's eggs can lie dormant in arid soil for several years until rain triggers their hatching. The hatchling nymphs thrive on the brief lushness that desert rains bring. When they've devoured everything in an oasis, they swarm to reach green regions beyond the desert. In the case of the Rocky Mountain locust, however, the swarming is more mysterious. These locusts never seemed to establish permanent populations beyond their home base in the Rockies.

When the young of swarming locusts hatch, they, too, are swarming locusts. The ability of grasshoppers to inherit traits their parents acquired was once a puzzle, for it seems to bypass the gradual genetic change that the theory of evolution predicts. Some entomologists describe this phenomenon as "cultural": The mother locust supplies her eggs with a heavier dose of nutrients and a chemical—called a maternal gregarizing agent—that encourage her offspring to develop toward the gregarious end of its potential. The environment into which it hatches (the jostling swarm itself) also constitutes a cultural influence. Such nongenetic inheritance is not unique; it has been observed in human populations when, for example, consistently good nutrition over several generations prompts an increase in average stature. The offspring of locusts born in a subsequent season may or may not develop into locusts; crowding is the deciding factor.

Pythons Prey on People and Other Mammals




A recent report in PNAS claims that reticulate pythons regularly prey on the Agta people of the Philippines. In The Book of Deadly Animals, I told of constricting snakes attacking and even killing people, but I questioned whether that actually happens in the wild. I also questioned whether snakes actually prey on people; in all the captive attacks I was able to discover, death was not followed by consumption. These scientists believe they have proof of both wild attacks and predation. (Thanks to Chuck and Croconut for the news tips.)




Today's news is full of pythons. First, new documentation that escaped constrictors (mostly Burmese pythons) are having an impact on the Everglades ecosystem:


BBC News - Pythons linked to Florida Everglades mammal decline: 


"They found that observations of raccoons and opossums had dropped by about 99%. There had been a 94.1% fall in observations of white-tailed deer and an 87.5% decrease in sightings of bobcats.


No rabbits or foxes were seen during the more recent survey; rabbits were among the most common mammals in the roadkill survey between 1993 and 1999.


The majority of these species have been documented in the diet of pythons found in the Everglades National Park. Indeed, raccoons and oppossums often forage at the water's edge, where they are vulnerable to ambush by pythons."




Meanwhile, in Uganda, wildlife authorities and police teamed up to capture pythons suspected of being used in witchcraft ceremonies. I haven't encountered such credulity since my last visit to West Memphis. Investigators found no pythons, though they did bag three rats. 

Hunger on the Wing (Part 1 of 3)

An African sky filled with locusts

Here’s another story from The Book of Deadly Animals. In the book, I didn’t have room for the whole story, since there were more than 900 other animals to talk about. This longer version first appeared in Discover.

*

One summer in the Oklahoma panhandle the grasshoppers were everywhere. Every patch of weeds along the alley would erupt like a pan of popping corn if I set foot in it. When we drove the highway, we inadvertently slaughtered dozens. The collisions speckled our windshield with hemolymph. Their wings, coffee-colored fans striped with yellow at the outer edges, lodged in our wipers and fluttered in the onrushing air. Sometimes an entire grasshopper, or most of one, would lodge there as well, struggling to get free as the wind tore it to tatters.

They could be found in unaccustomed places that summer. For several mornings running I saw two or three swimming in the dog's water dish. The rosebushes took on the riddled look of lace, as though the grasshoppers had tasted the leaves and found them unappealing but serviceable. In the country, the cedar posts of barbed wire fences would seem at a glance to be shimmering with heat, like a water mirage on the highway, but a second glance would show the effect was not an optical illusion. The posts were simply crawling with grasshoppers moving up or down for no apparent reason. They seemed to be moving with great caution, edging past each other. When a stationary grasshopper got bumped, it would draw its legs in tighter and shift its footing, like a person uncomfortable on a crowded bus.

Then there was the jackrabbit. We found it beside a dirt road on the way to the mailbox. It was dead, probably road-killed. Grasshoppers were thick in the weeds and grass along that road, and dozens clustered on the carcass. When someone poked at it experimentally, a few of the hoppers jumped off and opened their wings and were carried away by the wind. Others crawled off sluggishly. Some stayed put. With the carcass now more exposed, we could see that it was bald in patches, and that its hide was wounded in shallow divots, as if it had been hit all over with buckshot that failed to penetrate. It seemed that the grasshoppers had been eating it.

As the season wore on, the grasshoppers grew absurdly thick. Among the metallic green ones there were others, some yellow and spotted, others a brighter green. All these I was familiar with, though I had never made any particular study of them. But I began to see things utterly new to me. One grasshopper was black and flecked with gray, like burned charcoal. Another was black but flecked with a Tabasco red. This variety has been explained to me thus: In outbreaks, grasshoppers are so plentiful that they overwhelm their usual predators, offering them more food than they can use. Other grasshopper species, rare enough to go unnoticed most of the time, get relief from predators in this circumstance, and therefore are more likely to be around for people to notice.

Other things seemed different too—there were a great many large grasshoppers, thick as a lipstick. One morning on my driveway I found the largest specimen I had ever seen, a yellowish creature longer than a soda can. It was dead—a fact that gave me some comfort. Streams of black ants led up to its carcass. Their presence was the first thing that convinced me I was seeing a once-living creature rather than a toy. I turned it belly-up with a stick. Its head and thorax were intact, but its abdomen was riddled with holes. I had not seen this damage at first because its long wings concealed it from above. Through the holes I glimpsed ants working at the grasshopper's half-hollow hull.

What I've been describing is an infestation, a localized population suddenly grown orders of magnitude beyond its usual numbers. The causes are not thoroughly understood. In the United States, hot, dry weather has something to do with it—the heat lets grasshoppers grow faster, and the dryness discourages the fungi that would otherwise check the population's growth.

Swarms of locusts—giant flying species of grasshoppers—are a traveling variation on this phenomenon. They dominate a wide swath of this planet almost every year. Moving in groups of millions, the locusts migrate over great stretches of territory, settling down periodically to eat every bit of vegetable matter in sight. They are hunger on the wing.


In the United States migratory swarms of locusts are presumed to be a thing of the past. But a locust is really just an oversize grasshopper in a gregarious mood. When grasshoppers of certain species gather in great numbers, they begin to change their behavior. Normally, they are somewhat solitary. If forced together they seem uncomfortable, leaping away from each other. But hunger often forces them together when a bumper crop of grasshoppers encounters a meager supply of food and they must compete for it. If the crowding persists, the younger insects begin to change. The changes vary with the species, but in general their bodies grow to massive size. Their wings become clear and strong. Their colors shift dramatically—for example, from green and yellow to solid black. Their proportions alter, their shape essentially changing to accommodate flight. So profound is this change that scientists in the past have mislabeled the two phases, solitary and gregarious, as distinct species.

The creatures behave differently, too. They eat with shocking voracity. They whirl into the air in groups, forming swarm clouds. The swarms fly long distances, disrupting ecosystems for hundreds of miles. In the 1870s, one swarm was tracked from Montana to Texas, a distance of 1,500 miles. Polluted layers of glaciers high in the Rockies show that their flight sometimes takes them to altitudes beyond the normal range of grasshoppers. In 1874 a Nebraska doctor used telegraphs to find the far edges of a swarm he observed flying overhead, establishing that its area exceeded that of Colorado. Factoring in their rate and the depth of the swarm cloud, he arrived at an estimate of 12.5 trillion grasshoppers. The Guinness Book of World Records lists this swarm as the "Greatest Concentration of Animals" yet observed. More rigorous methods were used on a swarm in Kenya in 1954, yielding the figure of 10 billion grasshoppers in a swarm, which happened to be only one of 50 swarms in that country at the time.

Tigress Kills Farmer



In rural India, officials are tracking a tiger that killed a farmer. 

Killer tigress still at large in Patan Bori - Times Of India:

""The tigress continues to kill our animals, but the forest officials have not been able to track and capture her," said a villagers who lost his cow a few days ago.


When contacted, Chief Conservator of Forest Devendra Kumar confirmed the reports about tigress' attacks. "The tigress is attacking animals to teach hunting to her cubs," he said."

What Is This?: The Sequel--Answers



Answers to Wednesday's quiz, in which I asked the immortal question, What the heck is this stuff? Photography by Nik Nimbus.


1. Ice




2. Spider web coated with pollen.




3. Magpie's feather.




 4.Wings of a damselfly




5. Rhubarb leaf.



6. Tree sap.


Leopard Attacks Pregnant Woman



Two people, including a pregnant woman, have been hurt by a leopard in the same Indian city that has witnessed two other  attacks within a month. A total of nine people were injured in the attacks, one fatally. 


Akila Bibi: Pregnant woman, 20s, suffers horrific injuries in leopard attack in India's Guwahati | Mail Online: "Moziz Haq suffered head injuries.


Speaking from his hospital bed, he told AFP news agency: ‘It was a thumping, slap-like feeling and I fell on the ground with blood splattered all over me’.


The animal was later tranquilised by forest officials and taken to a city zoo."

Related Post: Earlier Leopard Attack

Hawk Eats Squirrel



Dee photographed this hawk in predatory action in the middle of the city. 















Photography by Dee Puett.

What Is This?: The Sequel

By popular demand, more of Nik Nimbus's amazing photos of the textures of living things. How many can you figure out?


Nik, by the way, has a new radio show, which I recommend highly. It's full of psychedelic sounds from bands like Evil Edna's Horror Toilet. I hadn't heard of Evil Edna's Horror Toilet, but it's easily the best named band in history. I'll be listening for more from them, as well as the Ullulators, Webcore, and Nik's own legendary band, Here and Now. 


1.



2.


3.



 4.



5.


6.

(Answers will appear Sunday.)

Sedaris Recommends Book of Deadly Animals

From David Sedaris's Facebook page:


David will be suggesting the book "The Book of Deadly Animals" by Gordon Grice as his next "Recommended Book" on his spring 2012 tour. Get a jump on your reading!

A Rash of Jellyfish in New Zealand

Biusch/Creative Commons


On the beaches of New Zealand, swimmers have lately been troubled by hordes of larval thimble jellyfish. I wrote about these troublesome critters in The Book of Deadly Animals:


The larvae of this jellyfish are popularly called sea lice, but they are not related to the tiny crustaceans of that name. Though microscopic, thimble larvae cause a rash which sometimes endures for weeks and brings on secondary infections. The larvae generally sting only when trapped by clothing, a habit which concentrates the stings in the areas of the body covered by the swimsuit. (I pause a moment to let you take in the implications.) The larvae can survive dried out for months. Some people have found themselves attacked all over again when they put on the swimming gear they peeled off and hung to dry the summer before.


As the article linked below mentions, some beaches have been troubled by more formidable cnidarians (as jellyfish and their relatives are called). The portuguese man-o'-war (pictured above) is one such relative, a colony that behaves like a single animal. Its stings are, on rare occasions, fatal.


Jellyfish invade Auckland beaches - National - NZ Herald News:

"A similar outbreak of sea bather's eruption occurred last February as La Nina's warm currents encouraged the spread of the jellyfish on eastern Auckland beaches.
The larvae are usually found in warm, still water and are rarely a problem at beaches with heavy surf, such as Piha.
Dr Baker said the only sure-fire way to avoid the rash was to not swim at affected beaches. But swimmers could lessen their risk by not wearing large, baggy clothing and by removing their togs on leaving the water.
Last month, thousands of jellyfish washed up on Wellington's south coast beaches, including the dangerous bluebottle or Pacific man o' war, sparking warnings from authorities.
And a swarm of bluebottles, including one with 2.5-metre-long tentacles, closed Oreti Beach, near Invercargill, this month."

Related Posts:
Giant Jellyfish Attacks New Hampshire
Diana Nyad vs. The Cnidarians

Bird-Eating Spiders




by guest writer J. Rodney Karr


for Maria Merian
Suriname 1692


Maria mixes reds inside sketched wings
of Rufous hummingbirds, thickens a line
on cylindrical tongues. Guyanan sun
shades pulps of unknown fruits that color four
brown spinnerets still wet enough to smear.
She has watched for hours whistling loops
and light ascensions to delicate nests
in spurge trees. Science is art. The sun gleams
from ruddish feathers puffed in display
and gilds the hairs upon the spider’s legs.
But there is no death within this sunlight,
only truth. The bird and spider now join
beneath the palm bark brush, within the branch
beneath Maria’s eye where nothing moves
except the hummingbird’s eye’s eventual light
and color and her mind’s eye, color, light.


Metamorphosis Insectorum Surinamensium,
her life’s work, translated from the Dutch,
is scrutinized beneath thought and eye, disbelieved
until an Australian zoologist
explores the Amazon. A woman’s mind
cannot be trusted. The scientist sees
a tiny bird within the light that moved
centuries before within Maria.
He sees the sudden brown dash, the flinch,
the fang’s repeated insertions to liquefy
the viscera, then the bird quickly dragged away.
Within his book he writes in praise of God
the sun in its exactness never lies.


This poem first appeared in Hayden's Ferry Review.
Painting by Maria Merian.

Bull Shark Kills Swimmer in South Africa

SaCaDeLik/Creative Commons


Zambezi shark is another name for the bull shark (Carcharhinus leucas).


Zambezi Shark Attacks, Kills Swimmer in South Africa - Animal Attack - ubAlert:

"A swimmer from Port St. Johns was attacked by a shark and fought with it for five minutes using his surf board. Unfortunately, the shark severely injured him in both arms and in the chest. "

Update: The Irish Times has further information on this attack, plus others over the last few years in this area. 


Meanwhile, the International Business Times has an article on recent shark attacks in Australia, including an attack by a ten-foot tiger shark and another apparently by a bull shark. 

Australia: Scrub Python Attacks Toddler

Mike/Creative Commons

Australia: Python Attacks Toddler, As Snake Tries To Suffocate Him | World News | Sky News:

"The child's mother said she heard the boy's "blood-curdling scream" and went to help but was unable to pull the snake off him.

Neighbours heard the mother cries and eventually freed the two-year-old victim.

The boy suffered four bite wounds after being attacked as he played with a ball in his back garden in Port Douglas.

The snake, which was not poisonous, bit his leg before looping itself around his body, his mother told the local Cairns Post newspaper."

Thanks to Croconut for the news tip.

Indonesia: Crocodile Killed After Eating Teenager



Disturbing news item from Indonesia. Several species of crocodile live in this area, but the likely predator here is the saltwater croc. 

Crocodile Killed After Eating Teenager | The Jakarta Globe:

"After killing the crocodile, people cut open its belly and found pieces of 14-year-old Rio Candra’s body.


“Parents now forbid their children from taking a bath in the river to prevent them from being eaten by a crocodile,” Syafullah said.


Rio was with his father, Syahrudin, looking for mangrove wood on the Merusi river when the crocodile attacked and dragged him into the water. His father, who witnessed the incident, could not do anything."

Thanks to Croconut for the news tip.

Crow Goes Sledding

Is this play, or something harder to understand? I sometimes see crows standing atop the pines in thunderstorms, riding as the wind whips them about. It's not a safe place to be; the only reason I can think of for standing there is that it's fun. 


Invasion of the Grebes



In Utah, a massive flock of eared grebes smashed into snowy parking lots, apparently mistaking them for water. Yet another lesson about blindly following your leaders.

Thousands of Birds Dive-Bomb Utah Parking Lots - Yahoo! News:
"Thousands came down. They came down everywhere. We were able to rescue about 2,000, but most of them, of course, didn't survive the impact."


What Is This?--Answers

Answers to yesterday's quiz:



1. The shed skin of a snake.




2. The feather of a pheasant.




 3. The hide of a leopard slug.




4. A mushroom.



 5. An orb-weaving spider.



 6. The fur of a badger.



Photography by Nik Nimbus.

What Is This?

A quiz for you. Here are photos of half a dozen natural objects seen in extreme close-up. All of them are (or were) part of living things-- like, for example, a wombat's toenail. How many can you figure out?

Photography by Nik Nimbus. 


1.



2.



 3.



4.


 5.


 6.


Answers tomorrow. Hint: "wombat's toenail" is not actually one of the correct answers. 

Related Posts Plugin for WordPress, Blogger...