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Maria Spivak : Pourquoi les abeilles disparaissent

Les abeilles ont prospéré pendant 50 millions d'années, chaque colonie de 40 à 50 000 individus coordonnée dans une harmonie incroyable. Alors pourquoi les colonies ont-elles commencé à mourir en masse il y a sept ans ?

Via Piotr Zut, Bernadette Cassel
Christian Allié's insight:

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...... Il se pourrait que cette espèce incroyable nous tende un miroir réfléchissant.

 

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Bernadette Cassel's comment, January 14, 2014 5:49 AM
Il se pourrait, Christian... Entendu parler de ça déjà... Et ici on voit bien la courbe, pour nous : http://www.europesolidaire.eu/article.php?article_id=879
Christian Allié's comment, January 14, 2014 6:58 AM
Merci Bernadette, redoutable rappel !
Avenir Adn Agri's curator insight, February 16, 2014 2:56 AM

Il est important de s'y intéresser et de participer à la protection et au développement des abeilles sur notre planète terre. Elles sont l'essence même de la pollinisation, berceau de notre alimentation !

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Aurait-on découvert la plus ancienne preuve connue de vie végétale sur Terre ? - SciencePost

Aurait-on découvert la plus ancienne preuve connue de vie végétale sur Terre ? - SciencePost | De Natura Rerum | Scoop.it
Une équipe de chercheurs annonce avoir découvert ce qui semble être la plus ancienne preuve connue de vie végétale sur Terre : deux fossiles de ce qui semblerait être des algues rouges vieilles de 1,6 milliard d’années suggérant que la vie multicellulaire avancée est apparue beaucoup plus tôt que l’on le pensait.

Les fossiles ont été découverts dans des roches sédimentaires de à Chitrakoot, dans le centre de l’Inde d’après l’étude publiée dans la revue PLoS One. Les traces, datées à 1,6 milliard d’années, précèdent de de 400 millions d’années le plus ancien échantillon connu d’algues rouges datées à 1,2 milliard d’années, suggérant ainsi que la vie multicellulaire a évolué beaucoup plus tôt qu’on ne le pensait et remettant en question la grande « explosion cambrienne » qui a donné lieu à la plupart des grands groupes d’animaux présents aujourd’hui sur Terre.

Via plantsci-UT3
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Study reveals mass extinction event 35 million years ago

Study reveals mass extinction event 35 million years ago | De Natura Rerum | Scoop.it
Australian National University biologists have found the first evidence of mass extinction of Australian animals caused by a dramatic drop in global temperatures 35 million years ago.

Via Mariaschnee
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"Many desert geckos also have strategies and attributes to avoid water loss, such as having relatively rugged skin and scales," he said. "The clear scale over the eye, called a spectacle or brille, is one such example of this, as it helps them avoid water loss from the surface of the eye.
But that means they can't blink, so they have to lick it clean. "Underwoodisaurus and their relatives Nephrurus have little 'eyebrows' that stick out to keep dust and dirt off their eyes, because they're burrowing species."

The pygopodoid geckos are a group of about 150 species found across Australia.

Read more at: https://phys.org/news/2017-03-reveals-mass-extinction-event-million.html#jCp
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Abstract Aerial Photographs of Southern Africa by Zack Seckler

Abstract Aerial Photographs of Southern Africa by Zack Seckler | De Natura Rerum | Scoop.it
Photographer Zack Seckler's latest series took him 2,000 miles through South Africa, each piece shot from the passenger seat of a two-seater sport plane. The works feature animal tracks and shadows as compositional elements, capturing herds of flamingos, gemsbok, and even a solo turtle resting in the dazzling blue water.

“From elevations between 50 and 500 feet, the landscape hovers on the line between things looking very real and recognizable and being more abstract,” said Seckler. “That’s what really draws me in—the line between reality and abstraction.”

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L’art de se cacher, un super-pouvoir de la Nature ?

L’art de se cacher, un super-pouvoir de la Nature ? | De Natura Rerum | Scoop.it

"... Le mimétisme est un mécanisme offensif ou défensif grâce auquel un animal se dissimule aux yeux de son prédateur ou à ceux de sa proie. Il s'agit, pour l'animal « déguisé », ou mimétique, de paraître ce qu'il n'est pas : un autre animal ou encore un élément inerte de l'environnement. Pour cela, il a recours à des artifices visuels, olfactifs ou comportementaux.

Il faut penser à différencier le camouflage du mimétisme. Il consiste à imiter des objets inanimés de l'environnement comme une feuille, une brindille (cas des phasmes), etc. Deux types de camouflage peuvent coexister : l'homochromie, qui est le mimétisme des couleurs et l'homomorphie, qui est le mimétisme des formes."

(...)

 

Noé, 08.03.2017


Via Bernadette Cassel
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Des araignées mangeuses d’oiseaux viennent d’être découvertes

Des araignées mangeuses d’oiseaux viennent d’être découvertes | De Natura Rerum | Scoop.it
Les araignées mangeuses d’oiseaux font partie des plus grandes araignées au monde. L’une des trois nouvelles espèces découvertes par les scientifiques aime auss

Via Hubert MESSMER @Zehub on Twitter
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Humpback Whales Are Forming Mysterious 'Super-Groups', and No One Can Explain It

Humpback Whales Are Forming Mysterious 'Super-Groups', and No One Can Explain It | De Natura Rerum | Scoop.it
They've never teamed up like this.

Via Mariaschnee
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Detect. Lock on. Intercept. The remarkable hunting ability of the robber fly

Detect. Lock on. Intercept. The remarkable hunting ability of the robber fly | De Natura Rerum | Scoop.it

Drones could use it — the remarkable hunting ability of the robber fly. 

 

A small fly the size of a grain of rice could be the Top Gun of the fly world, with a remarkable ability to detect and intercept its prey mid-air, changing direction mid-flight if necessary before sweeping round for the kill.

 

The robber fly Holcocephala is a relatively small fly -- at 6mm in length, it is similar in size of the average mosquito. Yet it has the ability to spot and catch prey more than half a meter away in less than half a second -- by comparison to its size, this would be the equivalent of a human spotting its prey at the other end of a football pitch. Even if the prey changes direction, the predator is able to adapt mid-air and still catch its prey.

 

An international team led by researchers from the University of Cambridge was able to capture this activity by tricking the fly into launching itself at a fake prey -- in fact, just a small bead on a fishing line. This enabled the team to witness the fly's remarkable aerial attack strategy. Their findings are published today in the journal Current Biology.

 

The robber fly has incredibly sophisticated eyes: like all flies, it has compound eyes made up of many lenses -- in the case of the robber fly, it is thought to have several thousand lenses per eye. However, unlike many species of fly, it has a range of lens sizes, from just over 20 microns to around 78 microns -- the width of a human hair. The larger lenses are the same size as those of a dragonfly, which is believed to have the best vision of all insects but is 10 times larger, and help reduce diffraction which would otherwise distort the image

 

"There's a trade-off going on between having excellent vision -- which requires bigger lenses -- and the size of the insect," explains Dr Paloma Gonzalez-Bellido from Cambridge's Department of Physiology, Development and Neuroscience. "The only way a robber fly could have vision as excellent as the 'poster child' of predatory insects, the dragonfly, across its entire visual field would be to have an eye with many more and larger lenses -- but then the fly itself would need to be much larger to be able to carry it."

 

To get around this problem, the robber fly has a concentration of larger lenses in the centre of its vision, accounting for only around one thousandth of its visual space. The lenses get smaller in size around the outside of the eye. Importantly, the team of researchers also showed that below the very large central lenses, this robber fly has evolved extremely small light detectors, which are placed almost parallel to each other and much further away from the lens than normal. This arrangement preserves the high local image resolution, which is very close to that of much larger dragonflies.

 

When it sees a potential prey, the fly launches itself upwards while maintaining a 'constant bearing angle' -- in other words, it moves in a direction such that while moving closer and closer to its prey, it still maintains the same relative bearing. This ensures that it will intercept its prey.

 

"If you think of this as though you're driving along the motorway and a car is coming down the slip road, then if the relative angle between you and this car remains constant, you will collide," explains PhD student Sam Fabian. "Of course, you'd take evasive action, but in the case of the robber fly, this is what it wants."

 

This strategy of maintaining the constant relative bearing also allows the robber fly to maneuver itself mid-air in the event that its prey changes direction. The researchers demonstrated this by switching the direction of their fake prey while the robber fly was mid-flight and observing how the fly responded. Once the fly is around 29 cm away from its prey -- though exactly how it judges this distance is still unclear -- the fly displays a remarkable strategy never before observed in a flying animal. It 'locks-on' to its prey while changing its own trajectory, enabling it to sweep round, slow down and come alongside the prey to make its final attack.

 

"What you see is similar to a baton pass in a relay race: when the two runners are heading in a similar direction and speed, they are more likely to be successful than if they are passing each other at ninety degrees," says Dr Trevor Wardill.


Via Dr. Stefan Gruenwald
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Clever bees learn new tricks from one another

Clever bees learn new tricks from one another | De Natura Rerum | Scoop.it
They may have tiny brains, but it turns out that bumblebees can not only learn to use tools by observing others, they can improvise and make the task even easier.

Via Mariaschnee
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Aerial Photos of Iceland That Look Like Abstract Paintings

Aerial Photos of Iceland That Look Like Abstract Paintings | De Natura Rerum | Scoop.it

"Andre Ermolaev is a Russian photographer who takes incredible aerial and landscape photographs. In his series entitled Iceland. River., Andre shows us the beautiful environment of Iceland from above.

The rivers and streams shown, which are carrying sediment from volcanoes and glaciers give the photos the incredible colours and textures. The photographs could easily be mistaken for abstract landscape paintings."


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« Le St Georges », l’autre chêne liège de La Londe-les-Maures (Var)

« Le St Georges », l’autre chêne liège de La Londe-les-Maures (Var) | De Natura Rerum | Scoop.it
Pour les fidèles lecteurs du Krapo arboricole, la simple évocation de La Londe-les-Maures devrait immédiatement vous rappeler un chêne liège absolument hors norme, probablement le plus spectaculair…
Christian Allié's insight:
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Je ne sais pas si les riverains ont donné un nom à ce splendide chêne liège. Alors je lui ai attribué le surnom de « St Georges » car on le découvre au milieu d’une plaine viticole en contournant une petite butte appelée Pic St Georges.
On remarquera également qu’un palmier opportuniste (que l’on nommera du coup « Georgette ») s’est installé dans le creux des branches.
Une situation qui n’a rien d’exceptionnelle même si l’on est plus habitué à trouver des figuiers opportunites.
Un autre palmier squatteur avait été présenté dans le parc Bir Hakeim à Perpignan, perché à 10m de hauteur dans un platane.
[...]
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Hubert Reeves : "Notre survie dépend des vers de terre" - leJDD.fr

Hubert Reeves : "Notre survie dépend des vers de terre" - leJDD.fr | De Natura Rerum | Scoop.it

"Nous faisons partie d'un immense écosystème, avec un monde animal et végétal qui nous est indispensable"

Christian Allié's insight:
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Dans ce combat pour la vie, entre ceux qui détruisent et ceux qui tentent de restaurer, qui va gagner?

Comment savoir? Je pense tout de même, au risque d'être dans l'utopie la plus totale, que nous devons agir. Parce que si nous partons du principe que c'est foutu, alors oui, c'est foutu! Il nous faut protéger la biodiversité, sauvegarder la fertilité des sols, stopper la surpêche…
Je lisais récemment un livre sur Jacques Cartier qui, lorsqu'il débarque au Canada en 1534, évoque des morues tellement nombreuses qu'elles gênent pour accoster. Aujourd'hui, c'est inimaginable.
Le pape François, en plaçant ces problèmes sur un plan moral, a eu raison. Que nous dit-il? Que si nos activités peuvent s'avérer catastrophiques pour des millions de personnes – c'est le cas avec les forages pétroliers ou gaziers qui amplifient l'effet de serre –, nous devons tout simplement les stopper.
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Tree-bark thickness indicates fire-resistance in a hotter future

Tree-bark thickness indicates fire-resistance in a hotter future | De Natura Rerum | Scoop.it
A new study has found that trees worldwide develop thicker bark when they live in fire-prone areas. The findings suggest that bark thickness could help predict which forests and savannas will survive a warmer climate in which wildfires are expected to increase in frequency.

Via Mariaschnee
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Eric Larson's curator insight, January 19, 9:23 AM
Bark thickness?
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Vidéo : le survol onirique des fjords de Norvège dans la brume

Vidéo : le survol onirique des fjords de Norvège dans la brume | De Natura Rerum | Scoop.it
Découvrez les fjords du nord de la Norvège sous un autre angle grâce à cette vidéo onirique et inquiétante réalisée à l'aide d'un drone.

Via Hubert MESSMER @Zehub on Twitter
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Non-breeding ravens live in highly dynamic social groups

Non-breeding ravens live in highly dynamic social groups | De Natura Rerum | Scoop.it
Ravens have impressive cognitive skills when interacting with conspecifics – comparable to many primates, whose social intelligence has been related to their life in groups. An international collaboration of researchers led by Thomas Bugnyar, Professor at the Department of Cognitive Biology, University of Vienna, could uncover for the first time the group dynamics of non-breeding ravens. The results help to understand the evolution of intelligence in this species and were published in the scientific journal Scientific Reports.

Several recent studies have revealed that ravens are among the most intelligent species of birds and even species in general. But which factors caused the evolution of intelligence? According to a common hypothesis life in social groups can drive brain evolution especially when individuals benefit from remembering the identity of conspecifics and the interactions with them. With such knowledge, animals can avoid conflicts with higher ranking group members or develop alliances to gain better access to resources.

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Amazon River no younger than 9 million years, new study shows

Amazon River no younger than 9 million years, new study shows | De Natura Rerum | Scoop.it
Researchers from the University of Amsterdam (UvA) and the University of Brasilia (Brazil) have determined the age of the formation of the Amazon River at 9.4 to 9 million years ago (Ma) with data that convincingly refutes substantial younger estimates. Their results are published as early view in the journal Global and Planetary Change.

The study comprised geochemical and palynological analyses of sediments from a hydrocarbon exploration borehole, situated offshore of Brazil, that reached more than 4.5 kilometers below sea level.

The results show a distinct change in sediment composition and plant residual matter during the late Miocene (9.4 to 9 Ma). This represents a switch in river source area from the tropical lowlands to the high Andes, which is diagnostic of the onset of the transcontinental Amazon River. The new data contradict younger estimates (c. 2.6 Ma) that have been proposed in recent literature and postdates estimates from an earlier study of this borehole by about 1 to 1.5 million years.

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Tous inégaux face aux piqûres de moustiques

Tous inégaux face aux piqûres de moustiques | De Natura Rerum | Scoop.it
Le virus a déjà fait cinq morts depuis le début de l’année dont des personnes âgées avec des antécédents médicaux. Pourquoi certaines personnes sont elles plus piquées que d'autres ? Quels sont les facteurs d'attraction des moustiques ?

Via Bernadette Cassel
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How plankton cope with turbulence

How plankton cope with  turbulence | De Natura Rerum | Scoop.it
Microscopic marine plankton are not helplessly adrift in the ocean. They can perceive cues that indicate turbulence, rapidly respond to regulate their behavior and actively adapt. ETH researchers have demonstrated for the first time how they do this .

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360-degree tour of the Palau corals

Palau's vibrant corals are thriving, despite some of the warmest and most acidic waters in the world. In this virtual reality experience, Lukas Isall fro

Via David W. Deeds
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David W. Deeds's curator insight, March 16, 9:56 PM

Check this out!

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Intact mushroom and mycophagous rove beetle in Burmese amber leak early evolution of mushrooms

Intact mushroom and mycophagous rove beetle in Burmese amber leak early evolution of mushrooms | De Natura Rerum | Scoop.it
Recently, a research team led by Professor Huang Diying from Nanjing Institute of Geology and Palaeontology reported a diversity of gilled mushrooms and mycophagous rove beetles from Burmese amber, the latter belonging to Oxyporinae, modern members of which exhibit an obligate association with soft-textured mushrooms. Their finding displays an ancient ecological community assembling diverse mushrooms and beetles and established on specialized trophic interaction by this early date.

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50 millions de données collectées sur les sites VisioNature ! - Actualités - LPO

50 millions de données collectées sur les sites VisioNature ! - Actualités - LPO | De Natura Rerum | Scoop.it
VisioNature est un carnet d’observation virtuel qui permet de saisir vos observations d’animaux et de les partager avec la communauté des contributeurs. Avec 50 millions de données collectées, VisioNature est devenu le plus important programme de science participative national.


Via Hubert MESSMER @Zehub on Twitter
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Le mammouth laineux s'est éteint à cause du changement climatique

Le mammouth laineux s'est éteint à cause du changement climatique | De Natura Rerum | Scoop.it
Une équipe américaine veut insérer des gènes de mammouth laineux chez un éléphant d'Asie et espère y parvenir dans deux ans, en 2019. L'idée, étrange, serait de protéger la toundr

Via Hubert MESSMER @Zehub on Twitter
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How pitcher plants evolved to become flesh-eaters

How pitcher plants evolved to become flesh-eaters | De Natura Rerum | Scoop.it
Carnivorous plants around the world all developed their killer habit in surprisingly similar fashion, according to a genetic study of distantly related pitcher plants from Australia, Asia and America.

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The Family Album of Wild Africa by Laurent Baheux

The Family Album of Wild Africa by Laurent Baheux | De Natura Rerum | Scoop.it
The Family Album of Wild Africa by Laurent Baheux.WITHIN LAURENT BAHEUX LIES A BURNING DESIRE TO PRESERVE NATURE’S PRIMITIVE SPECTACL

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Dazzling Images of Glowing Flowers Photographed With Ultraviolet-Induced Visible Fluorescence

Dazzling Images of Glowing Flowers Photographed With Ultraviolet-Induced Visible Fluorescence | De Natura Rerum | Scoop.it
28-year-old photographer Craig Burrows photographs plants and flowers using a type a photography called UVIVF or "ultraviolet-induced visible fluorescence." If you haven't heard of it, that's not a surprise, as it is a relatively unknown process which brings out the glowing fluoresce in plant matter

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This bay in Scandinavia has world record in carbon storing

This bay in Scandinavia has world record in carbon storing | De Natura Rerum | Scoop.it
Forests are potent carbon sinks, but also the oceans' seagrasses can store enormous amounts of carbon. A little bay in Denmark stores a record amount of carbon. Here is the secret.

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Eric Larson's curator insight, January 19, 9:22 AM
Carbon storing?