Tamara Rodrígez Olmos -Trimestre 1

Revista ''National Geographic'' - Diciembre 2012.

      *La estrategia de supervivencia notable pertenece a las hormigas de fuego de América del Sur, cuyos hogares en la selva están sujetos a inundaciones periódicas. Podemos ver la magnitud del poder de supervivencia de éstos animales, coordinándose en grupo. En menos de dos minutos, los insectos se propagan a través de la superficie del agua, se unen para formar una unidad resistente al ahogamiento. Es impresionante la inteligencia colectiva. Estos acontecimientos de la naturaleza también son de gran ayuda para el campo de la microrrobótica y las tecnologías hidrófugas.

  *Esta noticia nos hace darnos cuenta del daño que causamos en la naturaleza. Ni siquiera tendremos consciencia ni de la mitad de fatalidades que cometemos, entre éstas, la que ocurre con los escarabajos joya australianos, los cuales confunden botellas de cerveza que, despreocupadamente, tiramos a la naturaleza. Este hecho, llamado en el artículo ''atracción fatal'' provoca la muerte de muchos escarabajos que inocentemente intentan llevar a cabo su apareamiento, y acaban freídos al sol. Personalmente creo que con ésto todos deberíamos de tomar conciencia y procurar evitar este tipo de actos totalmente en contra de la naturaleza y de su hábitat.

 *Con tan solo unas 100 parejas reproductoras que quedan en estado salvaje, el Correlimos cuchareta se encuentra al borde del peligro de extinción. Esta ave migratoria se cría en el noreste de Rusia y que vive los inviernos en Bangladesh, en Myanmar (la antigua Birmania), Thailandia y algunas otras áreas del sureste asiático. Los cambios en su hábitat y las alteraciones en sus zonas de reproducción podrían ser algunas de las causas importantes en esta circunstancia, pero la pérdida de lugares para hacer escala en sus rutas migratorias son quizá las mayores dificultades, ya que en Corea del Sur y en China, han recuperado extensas áreas de marismas y humedales en zonas de cultivo agrícola. Mientras, en invierno en Birmania, éstas aves zancudas, son cazadas indiscriminadamente para alimento. En la actualidad, los investigadores están realizando tantos estudios como sea posible para obtener una idea clara de las causas del declive y sobre como tratar de que esta situación sea reversible y acaben por extinguirse. 

         Popular pesticide faulted for frog's sexual abnormalities.

     http://www.nytimes.com/2003/06/19/us/popular-pesticide-faulted-for-frogs-sexual-       abnormalities.html

Scientists from the Environmental Protection Agency say there is ''sufficient evidence'' to conclude that the country's most widely used pesticide, atrazine, causes sexual abnormality in frogs.

They are recommending that the agency conduct more research to understand atrazine's mechanisms and its broader impact on frog populations.  

The scientists noted that there had been six studies involving three species of frogs that show a variety of defects, including frogs with both multiple testes and multiple ovaries, when exposed to the chemical. The scientists cautioned that the results from studies of atrazine had not been consistent and that it was not clear at what levels of exposure those effects occurred or how different frog species were affected.

''Over several studies and environmental conditions and species, atrazine exposure did appear to be having some impact on gonadal effects,'' Tom Steeger, a scientist with the environmental agency's pesticide office, said on Tuesday in a presentation to an independent scientific panel convened here to assess atrazine's impact on amphibians.

Scientists hired by Syngenta, a major manufacturer of atrazine, said they drew different conclusions from available research.

''We see no correlation in the adverse gonadal effects and the introduction and use of atrazine,'' Glen Van der Kraak, a professor at the University of Guelph in Winnipeg, Manitoba, said in a presentation to the panel.

But E.P.A. scientists said many of the industry-sponsored studies had a variety of problems, including testing conditions that led to high mortality in their frogs. The four-day hearing by the panel, which ends on Friday, is an extension of the E.P.A.'s nine-year review of whether atrazine poses unacceptable risks to the environment and to public health. Later this year, the panel will make recommendations to the agency on how to proceed.

Atrazine and its byproducts are widely found at low levels in United States waters, especially after the planting season, when rains wash the chemical out of fields. It is popular with farmers because it is effective and relatively cheap. Atrazine has been banned in seven European countries.

Some laboratory studies have linked atrazine to cancer in rats, and some epidemiological studies show a correlation between exposure and cancer in humans.

The E.P.A. review had been moving toward renewing the agency's approval to use atrazine. But last year, a scientist at the University of California published two papers suggesting that low levels of exposure to atrazine, as low as one part per 10 billion in the water, could cause tadpoles to develop into frogs with both male and female sexual organs.

The studies, led by Tyrone B. Hayes, were published in April 2002 in the Proceedings of the National Academy of Science and in October 2002 in Nature magazine. Dr. Hayes had originally been hired by a consulting concern, Ecorisk, to conduct studies on atrazine on behalf of a company that is now Syngenta. The studies ignited a scientific and political debate, and led the environmental agency to convene the panel to examine atrazine and its effects on amphibians.

Initially, Syngenta said it had been unable to replicate the results of Dr. Hayes's work in company-sponsored studies. But since then, one of the company studies was published in a journal, Environmental Toxicology and Chemistry, and its primary author, Dr. James Carr of Texas Tech University, said the study did result in some hermaphrodite frogs, though at higher exposure levels than in Dr. Hayes's studies.

Dr. Hayes and other Berkeley faculty members present at meetings about his work say that when Dr. Hayes presented his findings to a panel of university scientists formed by Ecorisk, some of the panel members tried to delay him from publicizing his initial findings. Other scientists on the Ecorisk panel say any delay was intended to test the validity of the data.

Dr. Hayes left the panel in protest in November 2000, stating in his resignation letter that otherwise ''it will appear to my colleagues that I have been part of a plan to bury important data.''

Syngenta has submitted Dr. Hayes's initial work in an interim report to the E.P.A. The company has not submitted a final report on his research to the agency.

The two papers Dr. Hayes and his co-authors published in 2002 were based on research done without industry financing.

Tim Pastoor, who is in charge of global risk assessment for Syngenta, said, ''There were absolutely no constraints on any of the panel members on anything they have found.''

But the minutes from a January 2001 Ecorisk panel show Tim Gross, a University of Florida professor who is also part of the Ecorisk panel, telling Dr. Hayes that the ''results from the contracts are jointly owned'' by the company and the scientist. ''Therefore, publication is upon mutual consent,'' Dr. Gross said in a letter submitted at the meeting.

He said Dr. Hayes ''should be reminded of this, as well as the confidentiality of these results.''

The minutes were submitted to the environmental agency and obtained by the Natural Resources News Service through a Freedom of Information request.

But today, Dr. Hayes spent several hours presenting his research to the panel.

The atrazine discussion is a high-profile inquiry into the relatively new scientific area of endocrine disruptors, chemicals that at minute traces can significantly affect health by interfering with the hormones that regulate biological activity. Several studies from the last decade linked the trace pollutants to declining sperm counts, infertility and various forms of cancer in humans, as well as genital malformation in wildlife.

_______________________________________________________

* Once again we see the devastating effect in nature from pesticides created by humans. Atrazine and its byproducts are found at low Levels Widely in United States waters, especially after the planting season, when rains wash the chemical out of fields. It is popular with farmers because it is effective and relatively cheap. Atrazine has been banned in seven European countries.

Atrazine is the pesticide most frequently found contaminating groundwater, surface and drinking, because of its popularity. Eighty million pounds are used annually in the U.S., with rain spreading the pesticide far beyond its point of application.

It is not just about the survival of amphibians. Previous studies have shown that atrazine is a potent endocrine disruptor in fish, reptiles, birds, rodents and even human cells.

                           African spiny mice can regrow lost skin

             http://www.nature.com/news/african-spiny-mice-can-regrow-lost-skin-1.11488

Two species of African spiny mouse have been caught at something no other mammal is known to do — completely regenerating damaged tissue. The work could help improve wound healing in humans.

The species — Acomys kempi and Acomys percivali — have skin that is brittle and easily torn, which helps them to escape predators by jettisoning patches of their skin when caught or bitten. Researchers report today in Nature that whereas normal laboratory mice (Mus musculus) grow scar tissue when their skin is removed, African spiny mice can regrow complete suites of hair follicles, skin, sweat glands, fur and even cartilage.

Tissue regeneration has not been seen in mammals before, but it is common in crustaceans, insects, reptiles and amphibians. Some lizards can regrow only their tails, whereas some salamanders can regenerate entire limbs, complete with bones and muscle.

The researchers say that their next step will be to work out the molecular mechanisms and genetic circuits that direct the regeneration process. It’s unlikely that these mice have evolved an entirely new method of regrowing tissue, says Ashley Seifert, a developmental biologist at the University of Florida in Gainesville, who led the study. Rather, the genes that direct regeneration in salamanders are probably switched off in mammals, but have been switched back on in African spiny mice.

Seifert thinks that the ability to regenerate damaged tissue could even be switched on in humans. “By looking at the common genetic blueprints that exist across vertebrates, we hope to find the ones that we could activate in humans,” he says. “We just need to figure out how to dial the process in mammals back to do something the entire system already knows how to do.”

Jeremy Brockes, who studies limb regeneration in newts at University College London, agrees that it should be possible to use this work to improve wound healing in people. “The genomic resources are so powerful now that one could easily identify some aspect of regeneration in mice that could be helpful for human health,” he says.

The idea of regenerating entire limbs in humans may seem far-fetched, but regenerative medicine has made great advances in the past decade, with lab-grown bladders, stem-cell-seeded wind pipes and other regenerated human organs in part made possible through research on the genetic circuits humans share with flies, salamanders and mice.

Seifert says that this study is also a good example of how combining different fields of biology can lead to interesting results. “My initial conversations with a developmental biologist led me to chat with a mammalogist, eventually bringing me to field work in Africa with an ecologist, followed up by lab work with engineers, completed by molecular work,” he says. “Cross-talk among scientists can lead to really cool things.”

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* These two special species of African spiny mouse are able to completely rebuild a tissue   (they have a fragile skin) which makes them able to escape from predators easily.

 Tissue regeneration has not been seen before in mammals, but it is common in crustaceans, insects, reptiles and amphibians.

The importance of this discovery is that it could be studied in depth and it can be used to improve wound healing in people. This would be an important advance.

           Caribbean sardine collapse linked to climate change

http://www.scidev.net/en/agriculture-and-environment/biodiversity/news/caribbean-sardine-collapse-linked-to-climate-change.html

The collapse of sardine fisheries in the southern Caribbean Sea during the past decade may have been driven by global climate change, according to a study.

Researchers from the United States and Venezuela linked ecological measurements in the southern Caribbean Sea with global climate change indicators. These indices were revealed to correlate to changes in regional wind and seawater circulation patterns, which may have dire socioeconomic consequences for Caribbean countries — such as the collapse of valuable sardine fisheries.

The sardine, Sardinella aurita, feeds on plankton but since 2005, plankton levels in the Caribbean have reduced significantly, which, coupled with overfishing, may have contributed to the collapse of these fisheries — which plummeted by as much as 87 per cent, the study says.

The research team said that the decreasing levels of plankton production are the result of a reduction in ocean upwelling, whereby nutrients crucial for plankton production are brought from the sea's floor to the surface. The drop in upwelling has, in turn, been driven by changes in wind patterns and wind strength, themselves driven by global climate change. 

The conclusions are based on monthly measurements taken over a period of 14 years in the Cariaco Basin, off the northern coast of Venezuela. They were published in Proceedings of the National Academies of Science (PNAS), last month (15 October).

Researchers measured parameters such as temperature, salinity and the concentration of carbon dioxide in the seawater, said Yrene Astor, a researcher from La Salle Foundation of Natural Sciences, and a co-author of the study.

"The measurements in Cariaco are performed regularly, at monthly intervals, to see the trend over time for each parameter," Astor told SciDev.Net. "This revealed that water temperature has increased by 1.1 degree Celsius [since 1996] — a very slight increase, slow but steady."

The temperature increase contributes to the stratification of the sea, further limiting the upwelling and thus reducing plankton production.

But researchers are still unsure about whether the changes are driven by man-made climate change or natural climate variation, and, according to Astor, the project would need further measurements to determine whether or not the ecological shifts are man-made.

Funding for the Cariaco project has been guaranteed from the National Endowment for Science, Technology and Innovation of Venezuela up to 2014, Astor said.

Research in the Cariaco Basin is "the basis for understanding the low production of fisheries off the Venezuelan coast", César Lodeiros, a researcher at the Oceanographic Institute of Venezuela, told SciDev.Net.

The Venezuelan sardine catch has dropped from about 200 thousand tonnes in 2004 in to less than 40 thousand tonnes today, Lodeiros explained. "The same goes for other areas, because the abundance of plankton, generated by coastal upwelling, is the basis for the high production of fish and marine organisms on the Venezuelan coast, particularly in the East and West."

Lodeiros added that the Cariaco Basin investigation is also important because it reveals long-term trends in climate change impacts.

____________________________

* One of the main causes of the many deaths of these sardines is that, since 2005, plankton has been reduced in the Caribbean. Another one is about overfishing. But the most important cause is the global climate change. The increase of temperature contributes to the stratification of the sea, further limiting the upwelling and thereby reduce the production of plankton. Scientists are not sure if humans was the cause of this disaster.

Squeezed into smaller spaces, koalas now face deadly disease.

http://www.nytimes.com/2012/02/21/science/queensland-koalas-hit-by-chlamydia-infections.html

The koala, one of Australia’s most treasured creatures, is in trouble.

Faced with habitat loss, climate change and bacterial disease, koalas are being pushed into smaller and smaller regions of the country. In Queensland, the vast state in Australia’s northeastern corner, surveys suggest that from 2001 to 2008, their numbers dropped as much as 45 percent in urban areas and 15 percent in bushland.

And while climate change and habitat loss are affecting many other uniquely Australian animals, too — from birds and frogs to marsupials like wombats, wallabies and bandicoots — it is a bacterial infection that is worrying many scientists about the fate of the koala.

“Disease is a somewhat silent killer and has the very real potential to finish koala populations in Queensland,” said Dr. Amber Gillett, a veterinarian at the Australia Zoo Wildlife Hospital in Beerwah, Queensland.

The killer is chlamydia, a class of bacteria far better known for causing venereal disease in humans than for devastating koala populations. Recent surveys in Queensland show that chlamydia has caused symptoms in up to 50 percent of the state’s wild koalas, with probably even more infected but not showing symptoms.

The bacteria — transmitted during birth, through mating and possibly through fighting — come in  two different strains, neither the same as the human form. The first, Chlamydia pecorum, is causing a vast majority of health problems in Queensland’s koalas; the second, C. pneumoniae, is less common.

Unlike C. pecorum, the pneumoniae strain can jump to other species, but so far there is no evidence that it has spread from koalas to humans or vice versa.

Chlamydia causes a host of symptoms in koalas, including eye infections, which can lead to blindness, making it difficult for them to find scarce eucalyptus leaves, their primary food source. The bacteria can also lead to respiratory infections, along with cysts that can make female koalas infertile.

The epidemic has been particularly severe in Queensland, where nearly all koalas are infected with koala retrovirus, said Dr. Gillett. This retrovirus is an H.I.V.-like infection that suppresses the koala’s immune system and interferes with its ability to fight off chlamydia.

“In southern koala populations, where koala retrovirus is much less prevalent, normal immune functions tend to result in fewer cases of chlamydia,” Dr. Gillett said.

Treating chlamydia in wild koalas is a challenge, she said. The disease is so devastating that only a small percentage of the animals can be treated successfully and returned to the wild. And infected females often become infertile — a condition that cannot be reversed, so future population growth is affected as well.

There is no treatment available for koala retrovirus, but researchers are working to test a vaccine that would help prevent further spread of chlamydia infection in Queensland’s koalas.

A study published in 2010 in The American Journal of Reproductive Immunology found that this vaccine is both safe and effective in healthy female koalas. Further work is being done to test it in koalas that are already infected.

Peter Timms, a professor of microbiology at the Queensland University of Technology who is leading the effort to test the chlamydia vaccine in koalas, is hopeful that there will be another trial this year to test the vaccine in captive male koalas, followed by wild koalas. If all goes well, plans can be set in motion to distribute the vaccine more widely.

“It’s going to be impossible to vaccinate all wild koalas,” he said.

In Australia, there is no national plan to save the koala; it is up to each region to establish management plans for its koala population. Therefore, once the vaccine is shown to be completely safe and effective, Dr. Timms suggests targeting specific, threatened populations where capturing and releasing koalas would be practical, like those bordered on all sides by housing developments and roads.

Dr. Timms is also working on a single-dose form of the vaccine to make it more feasible to vaccinate wild koalas.

Another possibility would be to make vaccine distribution a routine part of treatment for the thousands of koalas brought into care centers every year after they are injured by cars or dogs, Dr. Timms said.

While it is a combination of problems that are affecting the wild koala population, many experts believe this vaccine would be an important step in helping koalas survive longer. It may buy enough time to give researchers a chance to solve some of the other problems facing Australia’s koalas.

“In situations where you combine habitat pressure, domestic dog attacks and car hits with severe chlamydial disease, the outcome for koalas is devastating,” Dr. Gillett said.

________________________________________________________________

*Koalas, one of the marsupials that identifies the Australian continent, are in danger of extinction due to a bacterial infection.

This is chlamydia, a disease that is transmitted in these animals at birth, periods of mating and during fights and that, according to the researchers, came to that nation by sheep brought by European immigrants.

The koala population has declined drastically in the past two decades and the infection from this pathology is the major cause.

                               The world's rare snake.

                        http://news.mongabay.com/2012/0710-hance-st-lucia-racer.html

It's slithery, brown, and doesn't mind being picked up: meet the Saint Lucia racer (Liophis ornatus), which holds the dubious honor of being the world's most endangered snake. A five month extensive survey found just 18 animals on a small islet off of the Caribbean Island of Saint Lucia. The snake had once been abundant on Saint Lucia, as well, but was decimated by invasive mongooses.

For nearly 40 years the snake was thought to be extinct until in 1973 a single snake was found on the Maria Major Island, a 12-hectare (30 acre) protected islet, a mile off the coast of Saint Lucia. After catching and tagging 10 individuals, scientists now believe 18 may survive in total. The island is free of the mongoose that have killed off the population of Saint Lucia. Non-venomous, the Saint Lucia racer feeds on local lizards.

"It was a huge relief to confirm that a population of the racer still survives," Matthew Morton, Eastern Caribbean Program Manager for the Durrell Wildlife Conservation Trust (DWCT), said in a press release, "but that relief is tempered by the knowledge of how close we still are to losing it forever."

The DWCT is working with Fauna & Flora International, the Saint Lucia National Trust, and the Saint Lucia Forestry Department to save the species with additional funding support from the Balcombe Trust, the Disney Worldwide Conservation Fund and the U.S. Fish & Wildlife Service.

Conservationists working with the Saint Lucia racer are closely looking at successful efforts to save the Antiguan racer (Alsophis antiguae). With a population that hit a nadir of 50 individuals in 1995, the Antiguan racer today has a population of over 900. Eradicating invasive predators, such as mongoose and rats, as well as education efforts have helped the Antiguan racer bounce back. Researchers are now looking to reintroduce the snake to more habitats as an insurance policy against extinction, especially as climate change raises sea levels.

"Tens if not hundreds of West Indian animals have already been lost because humans have unwisely released harmful species from other parts of the world, and we cannot allow the gentle Saint Lucia racer to be the next casualty" Jenny Daltry, Senior Conservation Biologist with Fauna & Flora International says. "To do nothing is not an option."

_________________________________________________________________

* It was a surprise to find this snake, called '' Saint Lucia broker'' (Liophis ornatus), that for 40 years was believed extinct.

It was rediscovered in 1973, only one in the Mayor Maria Island. It was about a mile from the coast St. Lucia, so this is the reason of his name.

The Mongoose caused their deaths, but now the island is free of mongooses.

This snake is not poisonous and only eat local lizards.

Now we have to try not to extinguish and preserve this species.

 ¿Son los pesticidas la clave de la disminución del número de las abejas?

               http://es.mongabay.com/news/2012/es0329-hance_beecollapse_pesticides.html

         

El uso de pesticidas puede ser la causa principal de la disminución del número de abejas, según dos nuevos estudios de la revista Science. Los estudios, uno centrado en abejas y otro en abejorros, hallaron que incluso una pequeña dosis de pesticida afecta al comportamiento y, finalmente, la supervivencia de estos animales, ya que atacan su sistema nervioso. Además, estos resultados pueden servir para cambiar la regulación para productos químicos de uso agrícola, o insecticidas neocotinoides, en uso desde los años 90. 

Los primeros registros alarmantes de la disminución del número de abejas comenzaron en América del Norte en 2006, donde algunos apicultores perdieron hasta el 90% de sus colonias. Desde entonces, se han dado situaciones similares en Europa y Taiwán. Se conoce como el problema de colapso de colonias y, en ocasiones, supone la pérdida de la mitad de la población adulta de una colonia de abejas. Estos colapsos vienen registrándose desde el siglo XIX, pero la crisis actual es mucho peor que las anteriores. 

A lo largo del tiempo, se han propuesto diversas teorías: enfermedades, ácaros parásitos, pérdida de hábitat y, por supuesto, pesticidas. Incluso, algunos investigadores sugieren que se trata de una combinación de todos estos factores. Pero tras años estudiando los pesticidas, ahora se han obtenido datos que demuestran que, aunque no son letales al instante, el uso de estos productos perjudica a las colonias de abejas. 

Primer estudio de caso: la falta de abejas reinas 

La mayoría de investigadores que estudian el problema del colapso de colonias se han centrado en las abejas, pero el mismo problema se da en los abejorros. 

«Algunas especies de abejorros han disminuido de manera drástica. Por ejemplo, en América del Norte, tipos que solían ser comunes casi han desaparecido del continente. En Reino Unido se han extinguido tres especies» explica Dave Goulson de la Universidad de Stirling, Reino Unido, coautor de un estudio que investigaba el impacto a largo plazo de los insecticidas neocotinoides en abejorros. 

El equipo de Reino Unido expuso abejorros comunes (Bombus terrestres) a pequeñas dosis, similares a las que hay en el campo, de un pesticida neocotinoide de uso común llamado imidacloprid. A continuación, los recluyeron en un ambiente controlado en el que podían vivir en condiciones naturales. Seis semanas después, pesaron las colonias y las compararon a las colonias controladas no expuestas. Las que lo habían sido eran entre un 8 y un 12 por ciento más pequeñas de las que no, lo que implica que los abejorros expuestos no estaban recolectando tanta comida. 

Pero fue aún más alarmante la falta de reinas. Las colonias expuestas a pesticidas produjeron un 85% menos de reinas: en total, alrededor de 1 ó 2 reinas por colmena. Las reinas son las abejas más importantes, porque fundan nuevas colonias tras el invierno, cuando todas las demás abejas mueren. No se sabe aún porque las colonias expuestas producen menos reinas, quizá es la consecuencia de recolectar menos comida. 

«Probablemente el impacto del imidacloprid en la reproducción del abejorro será sustancial y significativo, porque este producto químico se halla en 140 cultivos en más de 120 países» comentan los investigadores. 

Segundo estudio de caso: la desorientación de las abejas forrajeras 

Si bien el estudio anterior plantea el impacto de los pesticidas neocotinoides en la capacidad de recolección de las abejas, el presente estudio, también de la revista Science, puede haber dado con la causa. 

Científicos franceses insertaron minúsculos microchips en abejas europeas (Apis mellifera) para seguir sus movimientos. A continuación, administraron a algunas abejas pequeñas dosis de otro pesticida neocotinoide, llamado thiamethoxam. La probabilidad de que las abejas no regresaran del forraje era 2 ó 3 veces mayor en las abejas expuestas. Lo que significa que los pesticidas empeoran la orientación de las abejas, que se pierden y perecen. 

La desaparición de estas abejas por el contacto estos pesticidas supone un gran problema para las colonias. Además, se ha descubierto que cuanto más desconocido y complejo es el terreno, mayor dificultad tienen para encontrar el camino de vuelta. 

Tras el uso de simulaciones por ordenador, se estima que el impacto de los pesticidas en las abejas podría ser lo suficiente grave como para diezmar la población hasta llegar a un extremo sin solución. 

No es letal, pero sigue siendo mortal 

Pese a lo preocupante de la situación, estos resultados no son demasiado sorprendentes. Hace mucho tiempo que los investigadores se preocupan por el papel que los pesticidas neonicotinoides tienen en el problema del colapso de las colonias, ya que afectan su sistema nervioso. 

Pero ambos estudios muestran la relación entre el uso de pesticidas en el campo, en contraposición al laboratorio, y la disminución a gran escala del número de abejas. Como tantos otros productos químicos, el hecho de que los pesticidas neonicotinoides no maten a las abejas al instante, no significa que no tenga un efecto desastroso. 

«Nuestro estudio plantea cuestiones importantes sobre los procedimientos de autorización del uso de pesticidas. Hasta ahora sólo se necesita que los fabricantes aseguren que las dosis halladas en el campo no matan a las abejas, pero se ignoran las consecuencias que esas dosis no letales tienen en el comportamiento de las abejas» explica el autor principal de INRA, Mikaël Henry en Avignon, Francia. 

El uso de estos pesticidas es dominante en el medio ambiente y puede durar meses o años. 

«Los pesticidas sistémicos, en especial, se esparcen a través de los tejidos de las plantas a medida que crecen y acaban contaminando el polen y néctar. Por tanto, las abejas forrajeras están directamente expuestas, pero también el resto de la colonia, ya que al volver, almacenan y comparten material contaminado». 

De hecho, otro estudio publicado este mismo año en PLoS ONE encontró que abejas que habían muerto por el problema del colapso de colonias en Indiana contenían diferentes pesticidas en su sistema. Los mismos que se hallaban en el polen en las colmenas y en terrenos cercanos. 

La importancia de las abejas 

Las abejas son imprescindibles, ya que desarrollan un papel vital en una gran variedad de ecosistemas como polinizadores. Además proporcionan grandes beneficios económicos a los humanos, tanto por la producción de miel como por la polinización de numerosas frutas, verduras, frutos secos y flores. 

«Los abejorros polinizan muchos de nuestros cultivos y flores. El uso de estos pesticidas supone una amenaza para la salud y debe evaluarse». 

Se estima que las abejas aportan entre 8 y 12 mil millones de dólares tan sólo a Estados Unidos. 

_______________________________________________________________________

* Estamos ante la peor crisis hasta ahora en cuanto a la disminución del número de abejas. Los pesticidas que utilizamos, atacan a su sistema nervioso, provocando una afección a su comportamiento, y finalmente, a su supervivencia.

La primera alarma saltó en América del Norte en el año 2006. 

Los pesticidas nicotinoides no matan a las abejas al instante, pero provocan efectos desastrosos a largo plazo.

Hay que tener muy presenta de que la importancia de las abejas es enorme. Más de un cuarto de millón de plantas florales dependen de las abejas, así como muchas otras especies cruciales para la agricultura, y vegetales y árboles frutales que consumimos a diario. 

En mi opinión, deberían hacer un estudio mucho más riguroso de las dosis que pueden y deben ser aplicadas, dado que si no, estamos provocando, una vez más, el deterioro de nuestra fauna, y por consiguiente, nuestro planeta.

                        Irresponsabilidad en el zoológico.

                  http://www.20minutos.es/noticia/1428915/0/delfines/heorina/drogados/

El informe de toxicología realizado a dos delfines muertos en noviembre del año pasado en un zoológico de de Connyland, en Suiza, concluye que la causa del fallecimiento de los animales estuvo provocada por la ingesta de un sustituto de la heroína que fue hallado en la orina de los cetáceos.

Según una información del diario Express, los cetáceos no murieron, como se dijo en un primer infome, por el elevado volumen de la fiesta y por los antibióticos suministrados por los veterinarios, que fueron acusados de negligencia.

Ahora, meses después, otro informe de toxicología que se ha filtrado a los medios suizos sentencia que una sustancia llamada buprenorfina, un sustituto de la heroína, estaba presente en la orina de los dos animales, de nombre Shadow y Chelmers.

Tras esta conclusión, las autoridades y los responsables del parque creen que a los delfines alguien de la fiesta les dio la droga.

Nadja Gasser, empleada del parque de atracciones, aseguró tras conocerse el cruel destino de los cetáceos que "la muerte fuemuy dolorosa y se prolongó durante más de una hora".

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* Nos encontramos ante una noticia que deja una clara falta de responsabilidad ante un zoológico.

En primer lugar, la falta de consideración hacia los animales allí presentes, los cuales debieron sufrir fases de estrés debido a la contaminación acústica propia de una fiesta. Además de la presencia de numerosas personas y una desorganización propia.

Hay que resaltar la carencia de medidas de seguridad y vigilancia, dado que estos dos delfines fueron intoxicados con un sustituto de la heroína, la buorenorfina. Los cuales no solo el hecho de que muerieran, si no que esta ingesta (encontrada en restos de urea) les provocó un dolor prolongado.

Por lo tanto, deberían concienciarse, y pensar en el medio que les rodea y en el daño que pueden causar.

Y sobretodo, también, remarcar lo inapropiado que resulta realizar una fiesta en un lugar como lo es un zoológico, en el cual hay que tener delicadeza, control y vigilancia permanentes.