Organisation With A Difference-IYSN

India…the country of great legends…we have been the lands of brilliant minds…But recent years have seen the downfall and what we can call the export of Indian minds to countries abroad….We have become so blind in our quest of prosperity that we forget that it is our responsibility to give back something to this land which has made us capable enough to stand on our feet and speak our mind!!!

I have always felt that some day, the people of this country will give up on their selffishness and strive hard to make this nation-DEVELOPED!!!….This is exact reason why I felt proud when I came across the organization- INDIAN  YOUNG SCIENTISTS NETWORK (iysn.org)…This organisation is what I can call as-“by the students,for the students and towards the bright future of the students”…IYSN was is result of the brain work of young minds like Parth Upadhyay, Devang Agarwal, Utkarsh Singh and Nishi Anand….the most surprising fact being that all of them are 12th students….Brilliance at its best and that too at young age!!!

The guideline of the organisation “If we don’t have a platform, we create one.” itself describes their ideology.IYSN strives to work for those young scientists,scholars and exceptional students who are denied the proper platform to display their skills and ideas to the world.The organization guides these gifted students by supporting them with financial aid through scholarships.The main purpose of the organization is to call for new ideas which is sent forward to Mentors.By doing this,the site provides a way of interaction between the mentor and the student.The mentor if impressed paves way for that ultimate break through for your ideas.

The efforts of these young blood have made me aware of one thing…that not just in near the future but also in the many more generations to come INDIA is surely in safe hands….Please do be a part of this movement and make a difference to the bright future of our country!!!

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Genetic Engineering Makes Fish Glow!!!!

A genetically engineered fish that glows green from the inside out is helping illuminate what pollutants do inside the body.

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Zebrafish glow green under the microscope!!!

Endocrine disruptors are substances found in a wide range of industrial products, including plastics, as well as in many female contraceptives.

The chemicals mimic the actions of sexual hormones, resulting in various reproductive problems in both people and animals. Previous research has shown the chemicals that cause the fish to change gender and in people, endocrine disruptors have been associated with lower sperm counts and breast and testicular cancers.

Yet scientists have had difficulty tracking what endocrine disruptors do inside a person or an animal’s body. So a team genetically engineered zebrafish to glow in places where an endocrine-disrupting chemical is present—and thus show where it may be harming the body.

“We’ve essentially put genetic elements within the fish [embryos that], over time, that are specifically designed to identify where the chemicals penetrate and act within the body,” said study leader Charles Tylerat the U.K.’s University of Exeter.

“This genetic machinery produces proteins which don’t interfere with the way these chemicals act in the body, but they fluoresce green under a fluorescent microscope, providing a reporting system to identify which body tissues are being affected.

“This, in turn provides a more ‘intelligent’ way of identifying where the [pollutants’] potential health impacts might be” in people.

Glowing Fish Confirm Past Findings

Tyler and team exposed the zebrafish to varying levels of chemicals known to affect the hormone estrogen, including ethinyloestradiol, found in contraceptive pills; nonylphenol, present in paints and industrial detergents; and bisphenol A, a component of many plastics.

All of these substances have become common freshwater pollutants that are connected to problems such as gender changes in fish and decreased fertility and increased cases of cancer in people.

The researchers exposed the fish to different endrocrine disruptors at varying concentrations, and then used a microscope to see which of the small fish’s organs glowed—and thus responded—to the chemicals.

The data should help identify the thresholds at which the chemicals affect various tissues and organs in the body.

For instance, observing the glowing fish confirmed previous findings, such as a link between bisphenol A and heartproblems.

“We do see in this fish that the heart glows particularly in response to bisphenol A,” Tyler said. “So we can target the heart and try to look at the mechanics of what is happening.”

Tyler and colleagues also watched the chemicals light up other parts of the fish’s anatomy, including its eyes and skeletal muscles. Endocrine disruptors’ impacts to these parts of the body are unknown.

“It’s often been assumed that these chemicals impact the liver or testes or ovaries, but in these fish we’ve identified them in many different tissues, including parts of the brain,” he said.

For now, the fluorescent technology is limited to fish younger than six days old, because their skin has yet to develop pigmentation that would interfere with observing the fluorescence.

“The next phase is breeding these fish with a strain that lacks pigment in the skin,” which would allow the team to observe the fluorescent reactions in adult fish as well, Tyler said.

Courtesy-National Geographic

Why Pandas Love Bamboo???

A new analysis of panda poop has finally answered an age-old question: How do giant pandas survive on a diet that’s 99 percent bamboo when they have the guts of carnivores?

Plant-eating animals tend to have longer intestines to aid in digesting fibrous material, a trait the black-and-white bears lack.

What’s more, when the giant panda’s genome was sequenced in 2009, scientists found that the creature lacks the genes for any known enzymes that would help break down cellulose, the plant fibers found in bamboo and other grasses.

This led researchers to speculate that panda intestines must have cellulose-munching bacteria that play a role in digestion. But previous attempts to find such bacteria in panda guts had failed.

The new study looked at gene sequences in the droppings from seven wild and eight captive giant pandas—a much bigger sample than what was used in previous panda-poop studies, said study leader Fuwan Wei, of the Chinese Academy of Science’s Institute of Zoology in Beijing.

Wei and colleagues found that pandas’ digestive tracts do in fact contain bacteria similar to those in the intestines of herbivores.

Thirteen of the bacteria species that the team identified are from a family known to break down cellulose, but seven of those species are unique to pandas.

“We think this may be caused by different diet, the unique inner habitat of the gut, or the unique phylogenetic position of their host,” since pandas are on a different branch of the tree of life than most herbivores, Wei said.

Humans Drove Pandas to Bamboo?

Even with help from gut bugs, pandas don’t derive much nutrition from bamboo—a panda digests just 17 percent of the 20 to 30 pounds (9 to 14 kilograms) of dry food it eats each day. This explains why pandas also evolved a sluggish, energy-conserving lifestyle.

So how and why did pandas became plant-eaters in the first place?

Some scientists theorize that, as the ancient human population increased, pandas were pushed into higher altitudes. The animals then adopted a bamboo diet so they wouldn’t compete for prey with other meat-eaters, such as Asiatic black bears, in their new homes, said Nicole MacCorkle, a panda keeper at the Smithsonian’s National Zoo in Washington, D.C.

Pandas will eat meat if it’s offered to them, MacCorkle added, but they won’t actively hunt for it.

The panda-bacteria research appears in the October 17 issue of the journal Proceedings of the National Academy of  Sciences.

Courtesy-National Geographic

A Perfect Example Of Cloning Gone WRONG????

Are males necessary?

Maybe not for long, at least in an insect species whose females have begun to develop sperm-producing clones of their fathers—inside their bodies.

In the cottony cushion scale—a common agricultural pest that grows to about a fifth of an inch (half a centimeter) long—a new phenomenon has arisen: When some females develop in fertilized eggs, excess sperm grows into tissue within the daughters.

This parasitic tissue, genetically identical to the female’s father, lives inside the female and fertilizes her eggs internally—rendering the female a hermaphrodite and making her father both the grandfather and father of her offspring, genetically speaking.

Though this new form of reproduction hasn’t replaced cottony cushion scale sex, “this parasitic male has taken off like an epidemic in population,” said study leader Andy Gardner, an evolutionary theorist at the University of Oxford.

“Once [this trend] gets started, it’s going to sweep through the population so all the females carry it. So there’s no point for regular males to exist,” Gardner added.

If the females begin passing on the parasitic male to their offspring, there may eventually be no more need for “baby boy” cushion scales that grow up and produce sperm and fertilize females, Gardner said.

Gardner and the University of Massachusetts’s Laura Ross created a population model that predicted how females would respond to this infectious tissue living within their bodies. The results, published in the August issue of  The American Naturalist , suggest that the females would benefit from the infection, negating the need for males.

A cottony cushion scale mother and offspring.

Insect Sex Still a Mystery

Though the exact time line of male decline for the species is unknown, Gardner said, in the “long run, I’d expect the [insect species] to suffer because of asexuality.”

For instance, though 30 percent of animal species are asexual, in the “vast majority of cases, when we look at species that are asexual, they’re relatively recent [evolutionary] events … [and they] seem to go extinct quite rapidly.

“If you mate with yourself, that doesn’t generate the sort of adaptive variation that regular sex does.”

There are “obvious benefits” of straight-up sex, he said—the offspring get new combinations of genes that can make species overall more robust, he said.

Overall, it’s a mystery why there are so few insect hermaphrodites—only three species are known, all cushion scales. In general, insects are very sexually variable, reproducing in almost every way known to nature—including, in some species, males that can develop from unfertilized eggs.

Confusing matters, cushion scales are “not really hermaphroditic in the usual sense—it’s actually two ‘individuals’ in one body, [which] makes it more intriguing,” he said.

“We’re sort of groping around in the dark just now.”

Courtesy-National Geographic

Related Article-

Oldest Living Fossil Of Antarctic Whale Found

 Ancient jawbone suggests whales evolved more rapidly than thought.

The oldest known whale to ply the Antarctic has been found, scientists say.

A 24-inch-long (60-centimeter-long) jawbone was recently discovered amid a rich deposit of fossils on the Antarctic Peninsula.  

The creature, which may have reached lengths of up to 20 feet (6 meters), had a mouthful of teeth and likely feasted on giant penguins, sharks, and big bony fish, whose remains were also discovered with the jawbone.

The early whale swam polar waters during the Eocene period, some 49 million years ago. Its age suggests fully aquatic whales evolved from their mammalian ancestors more rapidly than previously thought, said researcher Thomas Mors, paleozoologist at the Swedish Museum of Natural History.

Based on 53-million-year-old fossils of whale-like, semi-aquatic mammals, scientists had thought mammals gave rise to whales in a process that took 15 million years. The new find suggests it took just 4 million years.

What’s more, “as soon as they became fully marine animals, they dispersed all over the world, showing the great success of the whale construction,” Mörs said in an email.

Whale Lived in Warm Antarctic

Not even cold waters were obstacles for early whales, he said—though Antarctica during the Eocene was much warmer than it is today.

The continent was green, carpeted in forests that housed marsupials and mammalian survivors from the dinosaur age, said Mörs, who is preparing a paper on the whale for publication in a journal.

“The shores were inhabited by colonies of penguins, among them giant ones. And the marine waters were still warm enough for leatherback turtles and a diverse shark fauna,” he added.

And ancient whales, too.

An abstract of the findings was published for the 11th International Symposium On Antarctic Earth Science held in July in Edinburgh, Scotland.

Courtesy-National Geographic

 

The List Of Disasters Introduced By Humans!!!

It has been Human tendency that we usually try things without thinking of the consequences….This is not limited to recreational activities….Now a days,with the advancements in science Human has become so reckless that He has started comparing himself to the greatness of God and enigma of Mother Nature….Ecological webs as designed by Nature was with due respect to the fact that harmony had to be maintained between the species….Some co-existing….some are predators….others are prey…..But a major balance was ALWAYS maintained!!!!…..But since we humans have this rebellious attitude to change things…..we went ahead and played with delicate web balance by some rather disastrous introductions….which have not just caused irreversible ecological damage but also caused major extinctions….Here is complete list of such measly mistakes done by Humans-

 10) Blackbird

No…This is not Jungle Crow….It is not even native of India… Blackbirds are native to Europe…. They were released into New York City between 1890 and 1891, supposedly in an effort to introduce all of the birds of Shakespeare into the United States….This is called hitting the hammer on your own feet….The numbers of these birds grew in huge numbers….When 3,000 of them try to sit on a telephone wire, it collapses…. When the birds  grazing on cattle feed, they eat enough to hurt dairy cows’ milk production and cost the farmer significantly in replacement grain….. When poisoned, they die in huge numbers…. thousands of carcasses fell from tree branches and landed around the city…..

Black Bird

9) Kudzu Vine-

The best example of weed which will grow from the ashes like pheonix is Kudzu vine….A hearty vine sat amongst the gladiolas and orange trees at the 1876 Centennial Exhibition, the first big World’s Fair in the U.S…. The exhibit was some North Americans’ first look at kudzu, an Asian plant….This is where everything started going worse….Soon sellers started buying this vine….This weed soon spread to all parts of the U.S…..As farmers and families moved to cities, the land was left to whatever grew the fastest….Growing unchecked from a backyard garden, it will climb over a house…. From the edge of a field, it will carpet an orchard or smother a forest….

Kudzu Vine

8 ) Brown Tree Snake

When we normally see a snake….we fear of our safety solely for the reason that it might bite us and we will dead within no time….Wish even the people in Guam had this fear….Because then they would not have allowed the Brown Tree Snake which reached there accidentally to survive …The people in that region let these cold blooded snakes roam thinking that they would get rid of snakes….But people were unknown to the fact that these snakes feast on the bird species in that region….Slowly these snakes grew to such large numbers that now they outnumber people in Guam….Almost 10 species of birds have become extinct….Now these snakes are busy finishing off the remaining two species….

Brown Tree Snake

7) Rabbit

Can you think that even rabbits can cause destruction….Romans were the first who domesticated rabbits….Rome collapsed….But they left behind rabbits….Once farmers started planting vegetables, which happened at an untimely moment — when the rabbits’ natural predators declined — it was unclear who was in control….The most amount of destruction is caused by wild rabbits…three of them can eat as much as sheep eats….Enough to cause a huge dent for agriculture and a hole in the pockets for farmers!!!

Wild Rabbit

6) Water Hyacinth-

This is what I called beautiful disaster….They are pretty and purple….But they are prolific weeds that double their population in 12 days….These plants pose a huge nuisance to processes that move water…. They clog irrigation systems and drainage canals, causing flooding, and shut down hydroelectric power plants…. They also block water travel, which in places like Papua New Guinea, where the water is the road, stops life…. By lowering the amount of light and oxygen in the water, they transform water ecosystems, choking out fish and other plants and eventually turning open water into marshes….

Water Hyacinth

5) Nutria-

These species are look so much alike the beavers….that no one would believe these cute looking species could cause so much destruction….They slipped into lakes and marshes, where they munch the tender shoots, water lilies and reeds….They pull the grass out…this actually robs many animals of their mating places,including the  endangered dragonfly in Japan….For people, the nuisance stemmed from the flooding that happened when marshes were no longer there to soak up water….Nutria have become great crop destroyers, ravaging Italian rice farms, sugarcane and sugarbeet fields, as well as alfalfa patches…..

Nutria

4) Bush Currant-

Absolutely yummy looking berries….But this bush is major invasive species….Hawaiians call it the purple plague, and Tahitians dub it green cancer….This plant was mainly imported for its green and purple leaves….But slowly it starting taking over entire forests when forest gaps opened because of fires or landslides….Bush currant uses sunlight better than other rainforest trees, and it grows fast. The tree shades out any seedlings that try to colonize the gap…Once it forms dense stands, it prevents water from soaking into the ground….The shallow roots also encourage erosion and landslides, so if the invaded patch is on a slope, it eventually falls off the hillside…. At that point, the land isn’t even suited to agriculture, since erosion strips nutrients….Bush currant threatens about half of the native plants on Tahiti with extinction….This proves that all good looking things may not be GOOD!!!

Bush Currant

3) Indian Mongoose-

We Indians have grown up listening to the story of Mangoose who saved his owners kid’s life from snake….and died instead…. It has e become a problem on islands, from Puerto Rico to Hawaii….mongoose was introduced to eat rats….But instead they started feasting on  local birds and reptiles, especially species that laid eggs on the ground….Their appetite for threatened and endangered species has driven a bird, the Fijian bar-winged rail, and a snake, the Hispaniola racer, to extinction. In fact, name an island, and the mongoose is likely eating the eggs of a threatened species there, from the pink pigeons on Mauritius to the Garman’s ground lizards on Grenada. And the rats are still eating the sugarcane….

Indian Mongoose

2) Mute Swan-

These are lovely invasive species….But they hog resources and exclude other birds…. In the 19th and 20th centuries, Americans and Canadians imported these natives of Europe and Asia to decorate zoos and parks…. After being let out or flying away, the birds landed in lakes, ponds and wetlands…. Swans proved to be bad neighbors….Extremely territorial, they claimed entire lakes, driving off and killing other birds that encroached…. They’ll even attack children who get too close…. After claiming a body of water, they overgraze underwater plants, further excluding other birds… In winter, they eat the roots of plants meant to sprout in the spring, again robbing other birds of food….They’ve gorged enough to drive water plants locally extinct…. It’s not only birds and plants that suffer; swans change the water community enough to threaten the fish….

Mute Swan

1) CANE TOAD-

Cane toads are native to Mexico, Central America and South America, where they hide in wet areas of the forest…. When introduced throughout the world, cane toads were intended to be a farmer’s friend….. They eat insects, and farmers released them to attack beetles in fields of sugarcane, banana and other crops…. Now cane toads are hopping around Egypt, Hawaii and more. As toads do, they’ve found wet places to live: drain pipes, which they clog, and drinking water tanks, which they foul….They sit under houses and belt out their mating call, which sounds like a telephone dial tone….As predators, they’re little poison bombs…. When a death adder, one of the world’s most poisonous snakes, swallows a cane toad, the death adder dies…. Certainly if pet dogs and cats eat the toad, they’re in danger…. The toad can also squirt its toxic secretions several feet, so to kill a pet, the animal needs only to paw. The toad has helped to poison Guam’s monitor lizards into decline, and it kills way more than its fair share of extremely deadly snakes in Australia….

Cane Toad

This list is exhaustive….The only way out is that we stop acting God….and let Mother Nature do her job well….Any more additions will be more destructive!!!!

A New Species Of Albino Spiders Discovered

Ever saw an Albino spider….No….but scientists in Australia have and are equally shocked about it!!!!

“I nearly fell over when I saw its white head,” Mark Harvey, senior curator at the Western Australian Museum, said via email.

The newfound trapdoor spider isn’t a true albino, since it still has some pigment—its body is brown, like those of other trapdoor spiders.

But the 1.2-inch-wide (3-centimeter-wide) arachnid has been dubbed the albino trapdoor spider until it’s formally described as a new species.

A person in a small town in western Australia found the strange-looking spider near his house, captured it in a jar, and sent it to the museum.

“Unfortunately we know nothing about its life history. We presume that they live in burrows for their entire lives—like all trapdoor spiders—and when males mature, they wander in search of females in their burrows,” Harvey said.

The newfound "albino" trapdoor spider.

Spiders That Pop Out for Prey

Trapdoor spiders get their name because they use soil, vegetation, and silk to construct doors to their burrows that are hinged with silk. The arachnids then pop out when they feel the vibrations of passing prey, which include insects, other arthropods, and small invertebrates.

The spiders also mate inside the burrows, where “males of all species probably have to lift the female body up to access her genital opening, which is located on the underside of the abdomen,” he said.

The new found spider is considered rare, Harvey added—it’s currently the only known specimen of its kind.

“Spiders are a diverse group of animals that fascinate and terrify many people,” though they’re crucial in keeping insect populations in check, he said.

“The world would be a poorer place without spiders.”

Courtesy-National Geographic

The Threat To Genetic Diversity….Because of Climate Change…

Climate change threatens species’ genetic diversity too

Mayfly-Much has been talked about how climate change poses risk to ecosystems and individual species. But no one has analysed how global warming will affect the genetic diversity hidden within the species.

DNA studies have revealed that traditional species contain a vast amount of “cryptic” diversity—such as different lineages or even species within species. “The loss of biodiversity expected in the course of global warming has been greatly underestimated in previous studies, which have only referred to species numbers,” says Steffen Pauls of Biodiversity and Climate Research Centre in Germany.

Researchers from Senckenberg Research Institutes and Natural History Museum in Gelnhausen, Germany, have made the first attempt to understand the link.

Mayfly

The team looked at aquatic insects living in the mountain streams of central Europe—seven species of caddisfly, and one each of mayfly and stonefly. The insects were chosen because they are likely to be vulnerable to rising temperatures—they need cold water, and have limited ability to travel large distances. To measure genetic diversity, the team sequenced genes in the insects’ mitochondria, energy-generating cellular organelles that have a small genome.

This allowed the authors to divide each species into a number of evolutionary significant units (ESUs)—the technical term for a population within a species that is genetically distinct from the rest of its kind.

Caddisfly-On the basis of where in Europe each ESU is found, the researchers then analysed whether other insects in the same group would be able to tolerate higher temperatures or move to somewhere cooler, using two models developed by the Intergovernmental Panel on Climate Change (IPCC). The study was published online on August 21 in the journal Nature Climate Change.

Caddisfly

They found that around 79 per cent of ESUs can become extinct by 2080 if the greenhouse gases emissions continue unabated. In case of reduced emissions 59 per cent of the ESUs were under risk of extinction.

“Our study also shows that species will survive but the majority of the genetic variations, which in each case exist only in certain places, will not,” says Carsten Nowak, lead researcher.

This means that self contained evolutionary lineages in other regions will become extinct, he adds. The authors note that knowledge about effect of climate change on genetic diversity is crucial to implement well-directed conservation strategies.

Commenting on the findings, Raghavendra Gadagkar professor at Centre for Ecological Sciences, Bengaluru says, “The techniques used by the researchers can now be readily applied to species of great economic importance such as agricultural pests or those of medical importance such as vectors of diseases.”

Courtesy-Down To Earth

The Truth Behind Fluorescent Scorpions!!!

Saguaro National Park, ArizonaHow do scientists find scorpions and certain other crawling animals in the dark, when a great many animals big and small are out and about in the desert night? They use a special light which makes the scorpions glow bright green, like the numerals on a watch.

Paul Marek, an entomologist at the University Of Arizona, tells us  how researchers went out at night during the BioBlitz this past weekend to look for scorpions and other nocturnal animals.

Fluorescence is where you have emission of radiation or light that strikes an object which re-emits the radiation or light at a different wavelength, Marek explained. “Black lights” are used to illuminate scorpions, which re-emit the light as green light.

Scientists know why scorpions are fluorescent like this, because of a nitrogenous substance in its cuticles, but what’s not known with any certainty is whether there is any purpose behind the fluorescence (other than to make it easy for humans to find them in the dark). “It’s a really easy thing to,” Marek said. “You go out at night into the Sonoran Desert with one of these UV lights and … these scorpions light up and glow like a little star field on the ground.”

Comparison- the scorpion as seen in normal light and its flourescent glow in dark

The photos above, show a scorpion glowing in a special light, compared with how the scorpion appears under regular light. Researchers aren’t quite sure if there is a reason why scorpions are fluorescent. Could it be a way for them to see one another in the dark?

The photos below are a selection of pictures made during the “inventory” to find nocturnal species in the Saguaro National Park BioBlitz. They were submitted by BioBlitz Photographic Ambassador Audrey Kanekoa-Madrid

Looking for scorpions this way, Marek said, confirmed a number of different species of scorpions are present in Saguaro National Park. “The most common ones we found were the Arizona bark scorpion, the striped scorpion, and the Arizona hairy scorpion.” The bark scorpion and the striped scorpion are the scorpions that cause the most medical problems, Marek said, because they pack the most venom.

Scorpions weren’t the only animals Marek and his team found in the BioBlitz of Saguaro. “We found some nice black widows, but what I didn’t know before is that their little spherical egg cases fluoresce. We also found some really nice big desert centipedes,” he said. It sounds like Saguaro is ready for Halloween!

Scorpions are an essential part of the ecosystem, Marek confirmed. “Scorpions are predators, so they feed on smaller arthropods, little cockroaches and flies … basically anything smaller than them … They keep herbivore populations down.”

Does anything eat scorpions? The southern grasshopper mouse preys on scorpions, Marek said. “They’re known as wolves in mice clothing. These little mice that actually bark … are like little ninjas. They go up and grab the scorpion, run around them, and can quickly chew off the tail of the scorpion, that has the stinger on it, so they can feast on the rest of it,” he said. Did the BioBlitz team see any of these ninja rodents during their field trip? “No, we didn’t see any of those, but the scorpions may have known about them,” Marek said.

Courtesy-National Geographic

Destroying The Invasive Species May Prove Very COSTLY???

Competition, not predation, is the most influential process that shapes food web

FOR centuries scientists have applied one golden rule to maintaining balance in an ecosystem—remove the invasive species. This rule may change soon.

A study has found that simply removing an invasive species, particularly a top predator, need not augur well for the invaded ecosystem; a complex ecosystem is never just about the predator and its prey. Position of prey in the food web is regulated more by what it eats than who eats it.A team of scientists led by New Zealand-based ecologist Wendy A Ruscoe investigated the consequences of the removal of top predator from a four-species food web comprising stoats, rats, possums and mice.

Stoat-One of Invasive Species

Stoats are common top predators in forests of New Zealand. They usually prey on rats which, in turn, compete with mice and possums for food. But possums give rats really tough competition. Mice do not compete with possums and stoats have no dietary interest in them either.

Based on outcomes of a previous simulation model, the team tested three established points: if reducing the stoat numbers would result in an increase in rat numbers, if reducing the number of possums would allow the rat numbers to go up, and if the mice numbers would shoot up in the absence of rats. The team chose four locations in the forests of central North Island and assigned two study sites to each location. Two sites at the first two locations were randomly assigned to either possum removal or possum and rat removal. The other sites were subjected to either control or stoat removal.

The results were unexpected. Whereas the simulation model suggested that removal of stoats would lead to increase in rat numbers, the experiments showed rats were unaffected by removal of their top predators. Rat numbers shot up in the possum removal sites. Mice numbers increased three times in the possum and rat removal sites. Possum numbers were low in the possum and rat removal sites and lowest in possum removal sites, as expected. No such response was seen in control or stoat removal sites.

The study, published in Ecology Letters in October 2011, shows that rat numbers were regulated more by competition for food with the possums rather than by predation. Going by the rule, if stoats were removed simply to give the rats a chance, the attempt would be a failed one.

So should one stop trying to manage invasive species? “Invasive species must be dealt with but understanding the consequences of removal must be considered beforehand. For example, invasive goat removal has affected native vegetation in these islands because the goats’ absence was responsible for increase in invasive weed species,” explains Ruscoe.

Asked whether the study applies to the recent removal of invasive Giant African snails in Kerala, TV Sajeev, scientist with the Kerala Forest Research Institute, replies, “We have not come across multiple species interactions with the Giant African Snail; neither did we find native species with the potential to replace the snail in the food web. The rule is that management of an invasive species is best done immediately after the invasion. When it has established itself, launching a single species eradication programme is not a good idea.”

Giant African Snail