Lazy crows pitch in when it counts: Nature Newsfreeloading crows start to contribute to group efforts
when hardworking birds become handicapped, a study shows. Carrion crows (Corvus corone) form stable groups that share the responsibilities of breeding
and caring for the young. Dominant breeders rely on helpers to feed chicks, but they also tolerate individuals that don't seem to help at all.
Puzzled about the reasons for this leniency, scientists have suggested that dominants may indirectly benefit from the survival and future reproduction of lazy relatives,
and that larger groups even those filled with dallying birds may have a lower risk of predation
The research team used camouflaged video cameras to collect data on how often 61 wild crows from 17 social groups in northern Spain fed chicks.
then trapped and clipped the wings of one bird from each group and repeated the data collection.
When clipped crows reduced their chick feeding by about 30, %only non-breeders intensified their care-giving efforts.
What's more, the laziest birds increased their helping behaviour the most. Five out of eight crows that had refused previously to visit the nest suddenly began feeding the chicks.
It's really important to investigate individual variability in helping behaviour because it could help us understand the evolution of cooperation,
Loitering crows may help the whole group by ensuring that provisions for offspring remain constant during tough times:
the increased effort of non-breeders compensated fully for the diminished offerings of the disabled crows.
or because dominant birds force them to contribute. Dawdling animals may be more likely to chip in voluntarily
if they are strongly related to other members of the group, because they may derive indirect gains from the group's overall reproductive success. The factors that influence helping behaviour are difficult to examine using skittish crows in the wild,
so Baglione next plans to use tame birds in aviaries. There's still a lot more to learn about how different individuals adjust their cooperative behaviour depending on the actions of others in the group he says.
I'd like to believe that this kind of study might shed some light on cooperation in humans
Bird blues: As many as 1, 240 bird species are threatened with extinction, amounting to 12%of the 10,027 recognized bird species,
says the latest update of the International Union for Conservation of Nature (IUCN) Red List of Threatened Species. The bird count was conducted by Birdlife International, a global partnership of conservation organizations.
The IUCN list also confirmed the extinction of the Alaotra grebe (Tachybaptus rufolavatus), 25 years after the last confirmed sighting.
The waterfowl, found mainly in Lake Alaotra in eastern Madagascar, is thought to have been killed off by poaching and the introduction to its habitat of carnivorous fish.
See go. nature. com/tswuze for more. Business Genzyme fined: On 24 may, the US Food and Drug Administration (FDA) fined Genzyme US$175 million for poor oversight at one of its manufacturing plants.
Efforts by the biotechnology company, based in Cambridge, Massachusetts, to clean the plant will cause shortages of three drugs,
including one used to treat thyroid cancer. But there was also good news for the beleaguered company:
so-named because the embryos of flies with a mutation in the polished rice gene lack the hairs that characteristically decorate the surface of the fruitfly embryo
it too generated subsurface oil plumes. That oil made its way around the Gulf, and at one point some beaches in Texas took an unexpected oil hit after it mixed with surface waters close to shore.
But I don't ride horses any more, she says. She also spends her days organizing her life's papers and memorabilia in the three-story family home,
and a pair of graphite walking sticks for when her balance goes awry. Yes, I e-mail, she says.
met less resistance when she encouraged village weavers to switch from artificial to natural dyes in the production of their woollen carpets and kilims,
which improved the weavers'business. That was very easy, she says. We showed them they could make more money.
a conservation biologist at James Cook University in Cairns, Queensland, Australia, and one of the authors of the analysis, to be published in the journal Conservation Letters1,
A nonprofit watchdog filed a lawsuit on 16 august to stop the construction of a US$4-billion weapons facility at Los alamos National Laboratory in New mexico.
¢go. nature. com/AD8G6E 22 28 august The 28th International Ornithological Congress discusses all things bird-related in Campos do Jord ae'£o, S ae'£o
The number of B. napus plants in each sample plot was counted and one plant was collected
The team found B. napus at nearly half of the 288 sites tested. Of these, 80%had at least one herbicide-resistant transgene (41%were resistant to Roundup and 40%resistant to Liberty.
and phosphate concentrations in animal feed in the country are much higher than Western standards, says Zhang.
and can release toxins that are poisonous to humans and animals. A study led by Liang Tao
Nandula Raghuram of the Society for Scientific Values, an ethics watchdog based in Delhi says that what should have been a rigorous assessment by India's top scientific institutions has ended up as the mouthpiece of Ananda Kumar,
a variety of aubergine modified to produce a protein from the Bacillus thuringiensis (Bt) bacterium that is toxic to insect pests.
making plants more threatened than birds, according to the first global analysis of the status of plant biodiversity.
Existing indicators of biodiversity such as the Red List of Threatened Species of the International Union for Conservation of Nature (IUCN) focus mainly on vertebrates,
Nature Newsplants made the evolution of large, complex animals such as predatory fish possible, a study of ocean sediments suggests.
that process led to higher animals such as ourselves, says Tais Dahl, an earth scientist at the University of Southern Denmark in Odense,
This created the right conditions for the evolution of large complex animals which require high levels of oxygen to survive.
A predator is near, you can sense it. Your heart races; you sweat. Quietly, you reach for a doughnut.
Stress speeds up the metabolism of grasshoppers, making them seek out easily digested sugars and carbohydrates for a quick energy boost.
In more relaxed conditions, many animals opt for high-protein foods that help them to grow
But with a predator lurking, they need fuel to quickly feed their amped-up bodies and to bolt,
In cages placed on naturally growing vegetation, Hawlena added grasshoppers and, in some cases, spiders with their mouthparts glued shut,
so that they could induce fear without killing the grasshoppers. Grasshoppers that were exposed to spiders switched from eating protein-rich grasses to munching on several species of sugary goldenrod plants.
Initially, this diet shift was thought to be related to how easy it is for grasshoppers to hide from spiders in the branched and flowering goldenrod.
To separate out the possible effects refuge-seeking Hawlena also studied grasshoppers and muzzled spiders in indoor terrariums.
Instead of plants, the grasshoppers were fed with an artificial diet of high-sugar or protein-rich'biscuits'and he saw the same trend.
Fearful grasshoppers went for the high-sugar cookies rather than the protein-rich bars1. All that sugary food means that the stressed-out insects are ingesting foods richer in carbon and poorer in nitrogen than their calmer,
protein-pumping cousins. Meanwhile, their bodies are breaking down proteins to make even more glucose. The result is a body that is made of significantly more carbon
and less nitrogen and thus makes poorer fertilizer when it dies and rots. Hawlena thinks that the ecosystem is likely to be changed in two ways by frightened grasshoppers.
First, they eat more goldenrod and less grass, changing the ratio of these species in the landscape.
Second, the soil is receiving less nitrogen, potentially influencing what can grow there. In ongoing experiments, Hawlena is getting intriguing results by looking at the different kinds of soil bacteria that thrive on stressed or unstressed grasshopper corpses.
He expects to see a similar story in the bodies of most other animals. The stressed-out living are likely to alter their diet,
and the relaxed and happy dead are likely to make better fertilizer2. Hawlena says that this phenomenon may help ecologists to understand previously unexplained ecosystem changes
Like Hawlena's grasshoppers, the elk of Yellowstone national park in Wyoming were thought to eat differently because of the threat of predation.
Some researchers proposed that the return of wolves to the park would cause elk to begin avoiding certain'risky'areas containing the predators.
That in turn would allow aspen trees munched into submission by the elk to begin growing back in those areas.
wolves could have a huge effect on the landscape. Alas not according to a recent study by Matthew Kauffman of the US Geological Survey in Laramie, Wyoming,
Tree rings and fenced-off experimental areas revealed that aspen growth didn't track well with wolf presence or absence.
The elk do change their behaviour in response to wolves and do avoid risky areas in general just not often enough to change the picture for aspen.
because elk that are near starvation as many often are in the winter are willing to take any risk to eat.
to say'to hell with wolves 'and feed there for a few days, says Kauffman. It remains to be seen
whether the physiological effects of stress on grasshoppers scale up to plants, soil, bacteria and onwards,
But that fact means ancient RNA might not be very useful for studying ancient animals such as mammoths.
Because the bones of animals are formed well after early developmental processes occur, you are getting a very different picture than you will be getting with seeds,
Nature Newsonce thought of as near total carnivores, early humans ate ground flour 20,000 years before the dawn of agriculture.
which kills the European corn borer (Ostrinia nubilalis). They found that since the crop was introduced in 1996, US farmers in the key maize-growing states of Iowa, Minnesota, Illinois,
Not only does Bt maize suppress the corn-borer population in fields planted with the GM crop
'lowering the pest population in conventional maize fields too. As a result, farmers planting non-GM CROPS benefit from fewer pests,
but don't have to pay the higher prices for the GM seeds. Overall, Hutchison's team found that corn-borer populations have declined by between 27%and 73%across the five states in the 14 years
since the transgenic crop was introduced. This work provides strong evidence for the reduced pest burden for non-Bt corn caused by the Bt corn, based on a reduction in overall pest-population size
says David Hopkins, director of science at the Scottish Crop Research Institute near Dundee, UK.
Conventional growers also help to stop corn borers becoming resistant to the Bt toxin by hosting pest populations that are susceptible to it, according to the team's research.
the corn earworm (Helicoverpa zea), has evolved resistance to Bt toxin in situations where GM-crop coverage is 100%.
and non-GM fields means pests that develop a tolerance can breed with susceptible populations from conventional fields,
so they could grow corn borers, says Hutchison, but over 14 years it's been very successful.
Hutchison says that the authors who work for industry provided data about corn borers and were involved not in the financial calculations.
Because the dung of grazing animals would be expected to contain a high proportion of wild plants,
They will have to come up with local adaptive strategies to make sure the animals have enough grazing land.
and perhaps suggest possible strategies for dealing with diminishing opportunities for nomads grazing their animals on the plateau.
Plight of the bumblebee: Nature Newsin a bid to curb the rapid decline in 10%of wild North american bumblebee species,
international researchers have agreed on the key scientific priorities that will drive the next steps including the establishment of a body to push forward research.
The United states and Canada are home to about 50 species of native bumblebees (Genus bombus), which are important wild pollinators of fruit and vegetable crops.
Several species have been domesticated and used for commercial pollination in tomato greenhouses. Honeybees tend to perform poorly in tomato pollination.
But in the last three years, researchers have identified five North american species that have undergone a relatively swift population reduction since the 1990s
For example, the Bombus franklini worker bee was widespread in northern California and southern Oregon in 1998,
and B. occidentalis will be submitted to the International Union for Conservation of Nature (IUCN) Red List of Threatened Species after a conference held at the Saint louis Zoo in Missouri on 9-12 november.
government agencies and commercial breeders to set future research priorities that might help to stem declines in bumblebee numbers.
such as finding the cause of the bumblebee disease thought to be behind the population crashes.
Some researchers have pinned the die off of native bumblebees on a fungal pathogen, Nosema bombi, which could have been introduced into the United states
when commercial bumblebees introduced into Europe by breeders then brought back escaped into the wild.
A related parasite has been implicated in the well-known decline of honeybees, although the two events seem to be unconnected,
says Ed Spevak, curator of invertebrates at the Saint louis Zoo, who also helped organize the conference.
and identify any other diseases possibly infecting the bumblebees. Other attendees concentrated on climate-change impacts that could be exacerbating the decline.
which may mean queen bumblebees find less nectar when they come out of hibernation. This group proposed long-term monitoring projects
In order to check the status of bumblebee populations across the United states conference participants suggested gathering and digitizing information from databases of different agencies,
Scientists at the conference also identified a need for basic research into bumblebee genetic diversity.
Attendees also agreed on a proposal to create an IUCN bumblebee specialist group that can coordinate the necessary research that will help policy-makers counteract the population loss.
many are hopeful that work from the conference will start to stem the bumblebee's decline.
Dengue control The release of male mosquitoes genetically engineered to be sterile can control dengue fever by suppressing the population of the insects that carry the disease, scientists at Oxitec,
They were reporting the results of a field trial of transgenic Aedes aegypti mosquitoes in a town on Grand Cayman
Malaysia will begin field trials of the mosquitoes in the next few months. See go. nature. com/6rxdjp for more.
has eclipsed the US Department of energy's Jaguar system at the Oak ridge National Laboratory in Tennessee. In the latest update to the list of the world's top 500 supercomputers (www. top500. org), released on 11 november,
with Jaguar managing 1. 75 petaflops. The United states still boasts five of the world's top ten fastest computers.
Ape deaths solved Japan's premier primate research centre says it has identified the cause of the mysterious series of deaths of its Japanese macaques (Macaca fuscata) that had puzzled researchers
) The Primate Research Institute of Kyoto University reported on its website on 11 november that the culprit was simian retrovirus-4 (SRV-4). The problem emerged
when the institute housed southeast Asian crab-eating macaques (Macaca fascicularis), which are natural carriers of the virus, with Japanese macaques.
The report said the virus had never been passed to humans. Events Cholera in Haiti The escalating cholera epidemic in Haiti had claimed more than 900 lives
on 16 17 november. go. nature. com/prqng2 21 24 november Officials from 13 countries with wild tiger populations meet at a global summit on conservation of the species in St petersburg, Russia
unlike the mouse version, it develops symptoms similar to those seen in humans with the disease, such as infection and inflammation in the lungs.
Sterile moths wipe out cotton pest: Nature Newsbetween May and October for four consecutive years, aeroplanes crisscrossed the morning skies above Arizona's cotton fields, dropping millions of tiny moths onto the croplands below.
The little grey insects are among the world's most notorious agricultural pests: their larvae are the pink bollworms (Pectinophora gossypiella), also known as'pinkies'.
'However, the moths released from the planes were different from those responsible for the caterpillars munching their way through the state's cotton crops.
They were sterile. The moth-drops were part of a programme to wipe the dreaded pinkie off the Arizona map for good.
State officials hoped that the combination of sterile moths and genetically modified cotton crops, engineered to produce a toxin deadly to pinkies,
would put an end to farmers'costly struggle against the caterpillars. The strategy was intended to restrict the spread of toxin-resistant pink bollworms by flooding the population with sterile moths.
When rare resistant moths emerged as they inevitably would, they would probably encounter a sterile partner,
and their genes would be erased from the population. It was a risky approach. To test the plan,
Arizona farmers had to give up the strategies normally used to suppress toxin-resistant bollworms so
if the sterile-moth strategy failed they could be faced with a bigger pinkie problem than ever.
When Bruce Tabashnik, an entomologist at the University of Arizona in Tucson, first heard about the scheme, he was worried.
My gut feeling was that this wouldn't work, he says. But as Tabashnik and his colleagues report today in Nature Biotechnology1
%The pink bollworm was gone all but. Sterile insect releases have already been used to drive down populations of the Mediterranean fruit fly,
or Medfly, in Guatemala, Mexico and the United states; screw-worms in the United states, Central america and Libya;
and tsetse flies on the island of Zanzibar, off the coast of Africa. The technique works best on pests that are not particularly populous.
If you have something like aphids or thrips, where there are thousands on a plant, it's kind of hard to release enough sterile insects to do any good,
says Fred Gould, an entomologist at North carolina State university in Raleigh, who wasn't involved in the study.
But where pinkies were concerned, genetically modified cotton crops had driven already down the population one million-fold,
says Tabashnik. The crops produce a toxin that is made naturally by the bacterium Bacillus thuringiensis called Bt toxin.
To prevent the spread of Bt resistance, farmers are required to plant nearby'refuges'of conventional crops.
The idea behind the refuges is to keep a population of non-resistant moths close at hand as potential mates for any resistant moths that arise.
Unfortunately, however, refuges also guarantee a steady local population of pink bollworms. After a while, farmers came to resent the refuges that allowed the bollworm to persist year after year,
costing them millions of dollars annually in crop losses and insecticide sprays. They asked the US Environmental protection agency for permission to dispense with the refuges
and instead begin releasing sterile moths. Still sceptical Tabashnik and his colleagues developed computer simulations to predict the consequences of the farmers'proposed strategy.
and sterile-moth releases could wipe out pest populations and stave off Bt resistance for at least 20 years.
In 2005, the Pink bollworm Rearing Facility in Phoenix began cranking out pinkies for the Arizona experiment.
The factory treated the moths with just enough radiation to damage the chromosomes in their reproductive cells without causing injuries that would prevent their survival in the wild.
about 2 billion pink bollworm moths were released into Arizona's cotton fields. By 2009, a survey of 16,600 cotton bolls from conventional crops yielded only two pink bollworm larvae,
and farmers had stopped using insecticide sprays to keep the pinkie population in check. So far, no live pink bollworm caterpillars have been found in bolls of cotton this season,
says Tabashnik. The results are tremendous says entomologist William Hutchison at the University of Minnesota in St paul,
Unfortunately sterile-insect release plans require extensive resources, Hutchison cautions. Plans to eliminate the pink bollworm from the United states and northern Mexico cost $30 million a year between 2006 and 2009.
In Arizona, says Tabashnik, it's conceivable that farmers will someday no longer have a use for Bt cotton at all.
whether pink bollworm is eradicated or not, it's a question of how economically damaging it is,
And in 2009 and 2010, pink bollworm was no longer an economically damaging pest in Arizona.
Mayans converted wetlands to farmland: Nature Newsthe ancient Maya civilization is recognized widely for its awe-inspiring pyramids, sophisticated mathematics and advanced written language.
including widely used laboratory animals such as fruitflies and mice. It banned the breeding of any GM organism
But in August, the ministry of agriculture published regulations for the law which seem to allow the contained use of GM plants and animals in education and research
African elephants are two distinct species: Nature Newsafrican forest-dwelling elephants (Loxodonta cyclotis) are a separate species from those living in the African savanna (Loxodonta africana),
researchers have shown. Scientists have debated long whether African elephants belong to the same or different species. They look very different,
with the savanna elephant weighing around 7 tonnes roughly double the weight of the forest elephant.
But studies had suggested they were the same species DNA in mitochondria (the cell's energy factories) from African elephants found evidence of interbreeding between forest and savanna elephants around 500,000 years ago2.
Now a group of scientists have taken a deeper look at the African elephants'genetic ancestry. The researchers sequenced the nuclear genomes of both types of African elephant
as well as that of the Asian elephant (Elephas maximus). ) They also extracted and sequenced DNA from the extinct woolly mammoth (Mammuthus primigenius) and mastodon (Mammut americanum) ancient elephant ancestors.
By comparing all these genomes, the team found that the forest and savanna elephants diverged into separate species between 2. 6 and 5. 6 million years ago.
The study is published online in the journal Plos Biology1. They split about the same time as African and Asian elephants split into separate species,
and much longer ago than people previously thought, says David Reich, a population geneticist at Harvard Medical school in Boston,
Massachusetts, and a lead author on the study. You can no more call African elephants the same species as you can Asian elephants and the mammoth,
he adds. Most researchers agree that the Asian elephant and the mammoth are separate species,
says Thomas Gilbert, a geneticist at the University of Copenhagen. But this study really hammers the coffin shut on any arguments that the forest
and savannah are anything but different species, or even genera, he says. MITOCHONDRIAL DNA can only give researchers information on maternal ancestry,
as this genetic material is inherited solely from the mother. Examining the nuclear genome which is around 200,000 times larger than that contained in mitochondria,
gives a broader and more accurate picture of elephants'history. You get a different picture by looking at nuclear DNA,
and savanna elephants interbred recently and had shared a recent female ancestor can be explained as a result of the female elephant's social behaviour,
the researchers say. Females tend to stay close to their place of birth, while the males roam. Herds of female forest elephants could have repeatedly come into contact
and bred with migrating male savanna elephants. Over a long period of time the forest elephant gene pool would become diluted
and displaced by that of the savanna elephants, but the forest DNA would be conserved in the MITOCHONDRIAL DNA,
which is passed on through the female line. What we see is an ancient split with a bit of gene flow more recently,
he says. Hybridization happens between closely related animals and does not necessarily imply that the two are the same species,
he says. The authors suggest that the findings will help to reprioritize elephant conservation programmes.
All African elephants are conserved currently as the same species . But the evidence that they are two distinct species suggests that they may be facing different pressures
and require different conservation strategies. The forest elephants should become a greater conservation priority, the study says.
Tide turns against corn ethanol: Nature Newsbuffeted by the economic crisis and a drop in the oil price,
and budget hawks who see the roughly US$6-billion-a-year benefit as wasteful spending on a mature industry.
On 8 december, its reusable'Dragon'capsule was launched on a Falcon 9 rocket from Cape canaveral, Florida.
hopes to dock Dragon with the station during its next demonstration launch, scheduled for 2011.
and it seems that honeybees are no different. Sleep-deprived bees are less proficient than their well-rested hive mates at indicating the location of a food source to other members of the colony by waggle dancing the figure-of-eight dance used to communicate the quality
and location of nectar supplies to the hive according to a study published online this week in the Proceedings of the National Academy of Sciences1.
Like all animals, European honeybees (Apis mellifera) rely on a sleep-like state of inactivity to survive
but sleep in insects and the effects of sleep deprivation on their behaviour are understood poorly. Barrett Klein who led the study as a graduate student at the University of Texas at Austin,
says that sleep deprivation could conceivably affect bees when hives are invaded by predators or parasites,
when apiculturists transport colonies over long distances, or as an everyday consequence of the busy nature of hives.
Bees bustle around, frequently bumping into each other, he says. It's also possible that sleep deprivation could exacerbate colony collapse disorder,
Klein and his colleagues devised a method to keep some bees within a colony awake without disturbing the rest of the hive.
They attached magnetic steel discs to 25 bees that had been trained to visit a feeder of sucrose solution located 1 kilometre away from the hive.
was passed back and forth along one wall of the hive for 12 hours, jostling the steel-tagged bees
and their well-rested copper-tagged hive mates for 48 hours, watching a total of 545 waggle dances.
The team found that steel-tagged bees were less able than those with copper tags to indicate the direction from the hive to the feeder (see videos of waggle dances performed by non-sleep deprived
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