Libellules: 2 Orthetrum assez ressemblants

 

Des Orthétrum photographiés au fil de mes balades cet été:

Skimmers I took this summer in my whereabouts in southern France:

 

 

Orthétrum réticulé en "coeur copulatoire", suspendu à une branche de saule:

Black-tailed skimmer in wheel on a willow branch:

Orthetrum cancellatum

Orthetrum cancellatum

 

Black-tailed skimmer female with a moth:
Orthétrum réticulé femelle avec une noctuelle:

Orthetrum cancellatum

 

Adult emale with a Small copper:
Femelle adulte avec un Cuivré commun:

Orthetrum cancellatum

Mâle à peine mature, on remarque ses cerques noirs:
Male just mature, notice the black cerci:

Orthetrum cancellatum

 

Orthétrum à stylets blancs
Les cerques*, au bout de l'abdomen, peuvent être entièrement blancs ou seulement partiellement:

White-Tailed SkimmerMature male, can be identified by the white (or partially white) anal appendages, the cerci* at the tip of the abdomen:

Orthetrum albistylum

Cerques: appendices anaux de la libellule qui permettent au mâle d'accrocher la femelle derrière la nuque pour l'amener à rabattre ses organes sexuels vers les siens (sous le thorax près de la jointure avec l'abdomen), ce qui forme le fameux "coeur copulatoire".

Cerci: male dragonfly appendages allowing him to grab the female behind the head and get her to bring her sexual organs (at the end of her abdomen) to his, under his thorax close to the abdomen.

L' attention sélective chez la libellule

In a discovery that may prove important for cognitive science, our understanding of nature and applications for robot vision, researchers at the University of Adelaide have found evidence that the dragonfly is capable of higher-level thought processes when hunting its prey.

Read more at: http://phys.org/news/2012-12-dragonflies-human-like-attention.html#jCp

The discovery, to be published online today in the journal Current Biology, is the first evidence that an invertebrate animal has brain cells for selective attention, which has so far only been demonstrated in primates. Dr Steven Wiederman and Associate Professor David O'Carroll from the University of Adelaide's Centre for Neuroscience Research have been studying insect vision for many years. Using a tiny glass probe with a tip that is only 60 nanometers wide - 1500 times smaller than the width of a human hair - the researchers have discovered neuron activity in the dragonfly's brain that enables this selective attention. They found that when presented with more than one visual target, the dragonfly brain cell 'locks on' to one target and behaves as if the other targets don't exist.

Read more at: http://phys.org/news/2012-12-dragonflies-human-like-attention.html#jCp

The discovery, to be published online today in the journal Current Biology, is the first evidence that an invertebrate animal has brain cells for selective attention, which has so far only been demonstrated in primates. Dr Steven Wiederman and Associate Professor David O'Carroll from the University of Adelaide's Centre for Neuroscience Research have been studying insect vision for many years. Using a tiny glass probe with a tip that is only 60 nanometers wide - 1500 times smaller than the width of a human hair - the researchers have discovered neuron activity in the dragonfly's brain that enables this selective attention. They found that when presented with more than one visual target, the dragonfly brain cell 'locks on' to one target and behaves as if the other targets don't exist.

Read more at: http://phys.org/news/2012-12-dragonflies-human-like-attention.html#jCpf

Odonata

In a discovery that may prove important for cognitive science, our understanding of nature and applications for robot vision, researchers at the University of Adelaide have found evidence that the dragonfly is capable of higher-level thought processes when hunting its prey

Read more at: http://phys.org/news/2012-12-dragonflies-human-like-attention.html#jCp

In a discovery that may prove important for cognitive science, our understanding of nature and applications for robot vision, researchers at the University of Adelaide have found evidence that the dragonfly is capable of higher-level thought processes when hunting its prey

Read more at: http://phys.org/news/2012-12-dragonflies-human-like-attention.html#jCp

Selective attention in dragonflies

In a discovery that may prove important for cognitive science, our understantding of Nature and aplications for robot vision, researchers at the Univerity of Adelaïde have found evidence that the dragonfly is capable of hight level thought processes when it hunts.

To read more, follow the link HERE.

In a discovery that may prove important for cognitive science, our understanding of nature and applications for robot vision,

Read more at: http://phys.org/news/2012-12-dragonflies-human-like-attention.html#jCp

Une découverte importante pour la science cognitive vient d'être réalisée dans le domaine de notre compréhension de la nature et de ses applications en matière de vision des robots.

Des chercheurs à l'Université d'Adelaide viennent de trouver la preuve que la libellule est capable d'avoir un processus de pensée bien plus élevé qu'on ne le pensait quand elle chasse une proie.
Elle possède donc des cellules cérébrales pour une attention sélective, ce qui n'a été démontré jusqu'ici que chez les primates.
 

 

 

Dr Steven Wiederman et son associé le  Professeur David O'Carroll (de l'Université du Centre d'Adelaide de la Recherche de Neuroscience) ont étudié la vision des insectes depuis de nombreuses années.

En utilisant une sonde minuscule en verre, dont le bout fait seulement 60 nanomètres de diamètre (1500 fois plus petit que la largeur de cheveux humains), les chercheurs ont découvert une activité neuronale dans le cerveau de la libellule qui lui permet cette attention sélective.
Ils se sont aperçu que la cellule de son cerveau se fixe alors sur une seule cible et elle se comporte comme si les autres cibles n'existaient pas.

Voir la vidéo ci-après qui en montre une en train de chercher une proie et se focaliser dessus une fois repérée, ignorant toutes les autres.
On la voit même réaligner son corps vers sa cible.

Elles sont capables d'en choisir une seule, même dans un essaim entier d'insectes, et de se tenir à celle-ci très précisément.

This is a video in the field showing a dragonfly on the hunt for prey -- shown at normal speed and then in slow motion. The dragonfly hovers while it searches for prey, moving its head and then repositioning its body, ready to pursue a target. When a target is identified (in this case a small fly), the dragonfly locks on and ignores all other potential targets. It swoops up and catches its prey. Credit: Associate Professor David O'Carroll, University of Adelaide. "Selective attention is fundamental to humans' ability to select and respond to one sensory stimulus in the presence of distractions," Dr Wiederman says. "Imagine a tennis player having to pick out a small ball from the crowd when it's traveling at almost 200kms an hour - you need selective attention in order to hit that ball back into play. "Precisely how this works in biological brains remains poorly understood, and this has been a hot topic in neuroscience in recent years," he says. "The dragonfly hunts for other insects, and these might be part of a swarm - they're all tiny moving objects. Once the dragonfly has selected a target, its neuron activity filters out all other potential prey. The dragonfly then swoops in on its prey - they get it right 97% of the time." Associate Professor O'Carroll says this brain activity makes the dragonfly a more efficient and effective predator. "What's exciting for us is that this is the first direct demonstration of something akin to selective attention in humans shown at the single neuron level in an invertebrate," Associate Professor O'Carroll says. "Recent studies reveal similar mechanisms at work in the primate brain, but you might expect it there. We weren't expecting to find something so sophisticated in lowly insects from a group that's been around for 325 million years. "We believe our work will appeal to neuroscientists and engineers alike. For example, it could be used as a model system for robotic vision. Because the insect brain is simple and accessible, future work may allow us to fully understand the underlying network of neurons and copy it into intelligent robots," he says. Journal reference: Current Biology search and more info website Provided by University of Adelaide

Read more at: http://phys.org/news/2012-12-dragonflies-human-like-attention.html#jCp

Ce qui semble évident pour les mammifères l'est beaucoup moins chez les invertébrés et les chercheurs ont été très surpris de découvrir ce phénomène chez des insectes qui vivent sur la planète depuis 325 millions d'années!

 La fonctionalité très succincte des neurones de libellule permettant une compréhension simplifiée elle pourra être facilement copiée pour l'ingénierie de la robotique.

The video

Read more at: http://phys.org/news/2012-12-dragonflies-human-like-attention.html#jCp

In a discovery that may prove important for cognitive science, our understanding of nature and applications for robot vision, researchers at the University of Adelaide have found evidence that the dragonfly is capable of higher-level thought processes when hunting its prey

Read more at: http://phys.org/news/2012-12-dragonflies-human-like-attention.html#jCp

In a discovery that may prove important for cognitive science, our understanding of nature and applications for robot vision, researchers at the University of Adelaide have found evidence that the dragonfly is capable of higher-level thought processes when hunting its prey

Read more at: http://phys.org/news/2012-12-dragonflies-human-like-attention.html#jCp

In a discovery that may prove important for cognitive science, our understanding of nature and applications for robot vision, researchers at the University of Adelaide have found evidence that the dragonfly is capable of higher-level thought processes when hunting its prey

Read more at: http://phys.org/news/2012-12-dragonflies-human-like-attention.html#jCp

In a discovery that may prove important for cognitive science, our understanding of nature and applications for robot vision, researchers at the University of Adelaide have found evidence that the dragonfly is capable of higher-level thought processes when hunting its prey

Read more at: http://phys.org/news/2012-12-dragonflies-human-like-attention.html#jCp

In a discovery that may prove important for cognitive science, our understanding of nature and applications for robot vision, researchers at the University of Adelaide have found evidence that the dragonfly is capable of higher-level thought processes when hunting its prey

Read more at: http://phys.org/news/2012-12-dragonflies-human-like-attention.html#jCp

In a discovery that may prove important for cognitive science, our understanding of nature and applications for robot vision, researchers at the University of Adelaide have found evidence that the dragonfly is capable of higher-level thought processes when hunting its prey

Read more at: http://phys.org/news/2012-12-dragonflies-human-like-attention.html#jCp

In a discovery that may prove important for cognitive science, our understanding of nature and applications for robot vision, researchers at the University of Adelaide have found evidence that the dragonfly is capable of higher-level thought processes when hunting its prey

Read more at: http://phys.org/news/2012-12-dragonflies-human-like-attention.html#jCp

In a discovery that may prove important for cognitive science, our understanding of nature and applications for robot vision, researchers at the University of Adelaide have found evidence that the dragonfly is capable of higher-level thought processes when hunting its prey

Read more at: http://phys.org/news/2012-12-dragonflies-human-like-attention.html#jCp

"What's exciting for us is that this is the first direct demonstration of something akin to selective attention in humans shown at the single neuron level in an invertebrate," Associate Professor O'Carroll says. "Recent studies reveal similar mechanisms at work in the primate brain, but you might expect it there. We weren't expecting to find something so sophisticated in lowly insects from a group that's been around for 325 million years. "We believe our work will appeal to neuroscientists and engineers alike. For example, it could be used as a model system for robotic vision. Because the insect brain is simple and accessible, future work may allow us to fully understand the underlying network of neurons and copy it into intelligent robots," he says.

Read more at: http://phys.org/news/2012-12-dragonflies-human-like-attention.html#jCp

This is a video in the field showing a dragonfly on the hunt for prey -- shown at normal speed and then in slow motion. The dragonfly hovers while it searches for prey, moving its head and then repositioning its body, ready to pursue a target. When a target is identified (in this case a small fly), the dragonfly locks on and ignores all other potential targets. It swoops up and catches its prey. Credit: Associate Professor David O'Carroll, University of Adelaide. "Selective attention is fundamental to humans' ability to select and respond to one sensory stimulus in the presence of distractions," Dr Wiederman says. "Imagine a tennis player having to pick out a small ball from the crowd when it's traveling at almost 200kms an hour - you need selective attention in order to hit that ball back into play. "Precisely how this works in biological brains remains poorly understood, and this has been a hot topic in neuroscience in recent years," he says. "The dragonfly hunts for other insects, and these might be part of a swarm - they're all tiny moving objects. Once the dragonfly has selected a target, its neuron activity filters out all other potential prey. The dragonfly then swoops in on its prey - they get it right 97% of the time." Associate Professor O'Carroll says this brain activity makes the dragonfly a more efficient and effective predator. "What's exciting for us is that this is the first direct demonstration of something akin to selective attention in humans shown at the single neuron level in an invertebrate," Associate Professor O'Carroll says. "Recent studies reveal similar mechanisms at work in the primate brain, but you might expect it there. We weren't expecting to find something so sophisticated in lowly insects from a group that's been around for 325 million years. "We believe our work will appeal to neuroscientists and engineers alike. For example, it could be used as a model system for robotic vision. Because the insect brain is simple and accessible, future work may allow us to fully understand the underlying network of neurons and copy it into intelligent robots," he says. Journal reference: Current Biology search and more info website Provided by University of Adelaide

Read more at: http://phys.org/news/2012-12-dragonflies-human-like-attention.html#jCp

Read more at: http://phys.org/news/2012-12-dragonflies-human-like-attention.html#jCp

Using a tiny glass probe with a tip that is only 60 nanometers wide - 1500 times smaller than the width of a human hair - the researchers have discovered neuron activity in the dragonfly's brain that enables this selective attention. They found that when presented with more than one visual target, the dragonfly brain cell 'locks on' to one target and behaves as if the other targets don't exist.

Read more at: http://phys.org/news/2012-12-dragonflies-human-like-attention.html#jCp

In a discovery that may prove important for cognitive science, our understanding of nature and applications for robot vision, researchers at the University of Adelaide have found evidence that the dragonfly is capable of higher-level thought processes when hunting its prey. Ads by Google Notary Publics - All Kinds Of Notary Services Available. Contact Us Today! - www.savillenotaries.com The discovery, to be published online today in the journal Current Biology, is the first evidence that an invertebrate animal has brain cells for selective attention, which has so far only been demonstrated in primates. Dr Steven Wiederman and Associate Professor David O'Carroll from the University of Adelaide's Centre for Neuroscience Research have been studying insect vision for many years. Using a tiny glass probe with a tip that is only 60 nanometers wide - 1500 times smaller than the width of a human hair - the researchers have discovered neuron activity in the dragonfly's brain that enables this selective attention. They found that when presented with more than one visual target, the dragonfly brain cell 'locks on' to one target and behaves as if the other targets don't exist.

Read more at: http://phys.org/news/2012-12-dragonflies-human-like-attention.html#jCp

In a discovery that may prove important for cognitive science, our understanding of nature and applications for robot vision, researchers at the University of Adelaide have found evidence that the dragonfly is capable of higher-level thought processes when hunting its prey. Ads by Google Notary Publics - All Kinds Of Notary Services Available. Contact Us Today! - www.savillenotaries.com The discovery, to be published online today in the journal Current Biology, is the first evidence that an invertebrate animal has brain cells for selective attention, which has so far only been demonstrated in primates. Dr Steven Wiederman and Associate Professor David O'Carroll from the University of Adelaide's Centre for Neuroscience Research have been studying insect vision for many years. Using a tiny glass probe with a tip that is only 60 nanometers wide - 1500 times smaller than the width of a human hair - the researchers have discovered neuron activity in the dragonfly's brain that enables this selective attention. They found that when presented with more than one visual target, the dragonfly brain cell 'locks on' to one target and behaves as if the other targets don't exist.

Read more at: http://phys.org/news/2012-12-dragonflies-human-like-attention.html#jCp

In a discovery that may prove important for cognitive science, our understanding of nature and applications for robot vision, researchers at the University of Adelaide have found evidence that the dragonfly is capable of higher-level thought processes when hunting its prey. Ads by Google Notary Publics - All Kinds Of Notary Services Available. Contact Us Today! - www.savillenotaries.com The discovery, to be published online today in the journal Current Biology, is the first evidence that an invertebrate animal has brain cells for selective attention, which has so far only been demonstrated in primates. Dr Steven Wiederman and Associate Professor David O'Carroll from the University of Adelaide's Centre for Neuroscience Research have been studying insect vision for many years. Using a tiny glass probe with a tip that is only 60 nanometers wide - 1500 times smaller than the width of a human hair - the researchers have discovered neuron activity in the dragonfly's brain that enables this selective attention. They found that when presented with more than one visual target, the dragonfly brain cell 'locks on' to one target and behaves as if the other targets don't exist.

Read more at: http://phys.org/news/2012-12-dragonflies-human-like-attention.html#jCp

In a discovery that may prove important for cognitive science, our understanding of nature and applications for robot vision, researchers at the University of Adelaide have found evidence that the dragonfly is capable of higher-level thought processes when hunting its prey. Ads by Google Notary Publics - All Kinds Of Notary Services Available. Contact Us Today! - www.savillenotaries.com The discovery, to be published online today in the journal Current Biology, is the first evidence that an invertebrate animal has brain cells for selective attention, which has so far only been demonstrated in primates. Dr Steven Wiederman and Associate Professor David O'Carroll from the University of Adelaide's Centre for Neuroscience Research have been studying insect vision for many years. Using a tiny glass probe with a tip that is only 60 nanometers wide - 1500 times smaller than the width of a human hair - the researchers have discovered neuron activity in the dragonfly's brain that enables this selective attention. They found that when presented with more than one visual target, the dragonfly brain cell 'locks on' to one target and behaves as if the other targets don't exist.

Read more at: http://phys.org/news/2012-12-dragonflies-human-like-attention.html#jCp

In a discovery that may prove important for cognitive science, our understanding of nature and applications for robot vision, researchers at the University of Adelaide have found evidence that the dragonfly is capable of higher-level thought processes when hunting its prey. Ads by Google Notary Publics - All Kinds Of Notary Services Available. Contact Us Today! - www.savillenotaries.com The discovery, to be published online today in the journal Current Biology, is the first evidence that an invertebrate animal has brain cells for selective attention, which has so far only been demonstrated in primates. Dr Steven Wiederman and Associate Professor David O'Carroll from the University of Adelaide's Centre for Neuroscience Research have been studying insect vision for many years. Using a tiny glass probe with a tip that is only 60 nanometers wide - 1500 times smaller than the width of a human hair - the researchers have discovered neuron activity in the dragonfly's brain that enables this selective attention. They found that when presented with more than one visual target, the dragonfly brain cell 'locks on' to one target and behaves as if the other targets don't exist.

Read more at: http://phys.org/news/2012-12-dragonflies-human-like-attention.html#jCp

In a discovery that may prove important for cognitive science, our understanding of nature and applications for robot vision, researchers at the University of Adelaide have found evidence that the dragonfly is capable of higher-level thought processes when hunting its prey. Ads by Google Notary Publics - All Kinds Of Notary Services Available. Contact Us Today! - www.savillenotaries.com The discovery, to be published online today in the journal Current Biology, is the first evidence that an invertebrate animal has brain cells for selective attention, which has so far only been demonstrated in primates. Dr Steven Wiederman and Associate Professor David O'Carroll from the University of Adelaide's Centre for Neuroscience Research have been studying insect vision for many years. Using a tiny glass probe with a tip that is only 60 nanometers wide - 1500 times smaller than the width of a human hair - the researchers have discovered neuron activity in the dragonfly's brain that enables this selective attention. They found that when presented with more than one visual target, the dragonfly brain cell 'locks on' to one target and behaves as if the other targets don't exist.

Read more at: http://phys.org/news/2012-12-dragonflies-human-like-attention.html#jCp

Prédation sur les libellules

Monstres mais à la fois victimes de harcèlements, ces dragons vivent dans un monde parallèle au notre, ou plutôt à l'image du monde humain... mais sans notre part d'humanisme...

L'émergence de l'imago est un moment crucial dans la vie de la libellule: sa sortie de l'exuvie est particulièrement à risque. Elle peut se faire attaquer par une armée de petite mouches ou de fourmis, par les nombreuses araignées qui guettent dans la végétation rivulaire ou bien encore la lymphe peut ne pas se résorber correctement et lui coller les ailes.

Dragon-fly predation

They can be monsters but also victims. These dragonflies live in a world parallel  to our, or rather in the image of the human world but without our part of humanism...

The emergence of the adult is a crucial moment in their lives: the emergence from the exuvia is particularly at risk. It can be attacked by an army of flies or or ants, by also by the many spiders spying in the water vegetation; or the lymph might not be absorbed entirely and stick its wings together.

Victime d'une émergence ratée, ici Libellula fulva:

A failed emergence:

Victime d'une attaque après l'émergence, les derniers segments de l'abdomen de ce Sympêtre strié ont été sectionnés:

Victim of an attack, the last abdomen segments were chewed off:

 

Un prédateur (oiseaux, petits mammifères ou odonates) s'est peut-être attaqué à celle-ci, ou bien une chute pendant l'émergence...

This one could have fallen vitim to a predator:

mais elles prélèvent aussi des proies, éliminant ainsi bon nombres d'insectes, libellules incluses.

But they are great predators themselves and eliminate a good deal of insects:

Entre ses pattes, un criquet paralysé de trouille!

Between its legs, a cricket frozen in fear!

Les Erystales semblent être assez prisées et font souvent les frais des banquets! 

La proie est immédiatement décapitée et les pattes tombent les unes après les autres pendant que le thorax et l'abdomen sont ingérés:

Tu peux la garder... je les préfère grillées! LOL!

Keep it... I prefer them fried! LOL

Le baiser de la mort

On ne peut pas à proprement parler de cannibalisme ici: ce sont 2 espèces différentes.

Mais une grande faim amène souvent une libellule à en dévorer une autre. Dans ce cas-là, une femelle d'Orthétrum réticulé adulte se rassasie d'un Sympêtre strié immature pour reprendre des forces entre 2 pontes:

Predation on another dragonfly to regain strength between two laying of eggs:

Le vol de la libellule - Flight of the dragonfly

Les ingénieurs électriciens de l'Université de Duke ont développé un système de télémétrie sans fil, léger mais assez puissant pour permettre aux scientifiques d'étudier l'activité neurologique complexe des libellules lorsqu'elles capturent leurs proies.
Jusqu'à présent, les études passées sur le comportement des insectes ont été limitées par la difficulté de collecter des données et les méthodes sont trop lourdes pour leur permettre d'agir de manière normale, comme ils le font dans la nature. Le nouveau système n'utilise pas de batteries, mais plutôt envoie le courant par rayon à la libellule qui vole.

 Cordulie bronzée, mâle  en observation

  Cordulia aenea - Cordulidae

 Downy emerald

 

En essayant de mieux comprendre le système de commande du vol complexe des libellules, ces ingénieurs collectent leurs informations en attachant des électrodes minuscules aux cellules nerveuses individuelles dans le système nerveux de la libellule et enregistrant l'activité électrique des neurones de la libellule et des muscles. Des systèmes existants pour enregistrer l'activité neurale exigent des batteries beaucoup trop lourdes pour être portées par une libellule; les expériences ont donc jusqu'à présent été effectuées avec des libellules immobilisées.

 Libellule déprimée, femelle  en ponte 
 Libellula depressa - Libellulidae

 The Broad-bodied Chaser

 

Si le nouveau système s'avère fructueux, les chercheurs s'attendent à ce que de nouvelles et passionnantes possibilités dans le comportement de petits animaux s'ouvrent pour la première fois:

Les chercheurs ont développé un système sans fil qui évite la taille et le poids d'une batterie.

Le système fournirait assez de puissance à la puce attachée à une libellule volante pour qu'il puisse transmettre en temps réel les signaux électriques d'un grand nombre de ses neurones.

Libellule fauve mâle en observation

Libellula fulva - Libellulidae

 Scarce Chaser

 

Le système pourrait envoyer assez d'énergie depuis la puce pour permettre de renvoyer des masses de données à plus de cinq mégabits par seconde, ce qui est comparable à une connexion à Internet privée moyenne. Les scientifiques cherchent à synchroniser les données neuronales et les réunir par le biais de la puce à une vidéo haut débit alors que l'insecte est en  vol.

La puce, avec deux antennes fines comme des cheveux sera fixée sous l'insecte pour ne pas gêner le mouvement de ses ailes, la puce devant avoir un contact radio ininterrompu avec l'émetteur.

Orthetrum réticulé femelle en ponte 

Orthetrum cancellatum - Libellulidae

Black-tailed Skimmer

  

  
Flight of the dragonfly:

Past studies of insect behavior have been limited by the fact that today's remote data collection, or telemetry, systems are too heavy to allow the insects to act naturally, as they would in the wild. The new system uses no batteries, but rather beams power wirelessly to the flying dragonfly.

Duke electrical engineer Matt Reynolds, working with Reid Harrison at Intan Technologies, developed the chip for scientists at the Howard Hughes Medical Institute (HHMI), who are trying to better understand the complex flight control system of dragonflies. They gather their information by attaching tiny electrodes to individual nerve cells in the dragonfly’s nerve cord and recording the electrical activity of the dragonfly's neurons and muscles. Existing systems for recording neural activity require large batteries that are far too heavy to be carried by a dragonfly, so experiments to date have been carried out with immobilized dragonflies.

If the new system proves successful, the researchers expect that broad new avenues into studying behavior of small animals remotely will become available for the first time.

“We developed a wireless power system that avoids the need altogether for the size and weight of a battery,” said Reynolds, assistant professor of electrical and computer engineering at Duke’s Pratt School of Engineering. He presented the results of his work today at the annual Biomedical Circuits and Systems Conference, held by the Institute of Electrical and Electronics Engineers (IEEE) in San Diego.

“The system provides enough power to the chip attached to a flying dragonfly that it can transmit in real time the electrical signals from many dragonfly neurons,” Reynolds said.

The chip receives power wirelessly from a transmitter within the flight arena in which the experiments are carried out. The system can send enough power to the chip to enable it to send back reams of data at over five megabits per second, which is comparable to a typical home internet connection. This is important, the scientists said, because they plan to sync the neuronal data gathered from the chip with high-speed video taken while the insect is in flight and preying on fruit flies.

“Capturing this kind of data in the past has been exceedingly challenging,” said Anthony Leonardo, a neuroscientist who studies the neural basis of insect behavior at HHMI’s Janelia Farm Research Campus in Virginia. “In past studies of insect neurons the animal is alert, but restrained, and observing scenarios on a projection screen. A huge goal for a lot of researchers has been to get data from live animals who are acting naturally.”

The average weight of the dragonfly species involved in these studies is about 400 milligrams, and Leonardo estimates that an individual dragonfly can carry about one-third of its weight without negatively impacting its ability to fly and hunt. Currently, most multi-channel wireless telemetry systems weigh between 75 and 150 times more than a dragonfly, not counting the weight of the battery, which rules them out for most insect studies, he said. A battery-powered version of the insect telemetry system, previously developed by Harrison and Leonardo, weighs 130 milligrams -- liftable by a foraging dragonfly but with difficulty.

The weight of the chip that Reynolds and his team developed is just 38 milligrams, or less than half of a typical postage stamp. It is also one-fifth the weight and has 15 times greater bandwidth of the previous generation system, Reynolds said.

The researchers expect to begin flight experiments with dragonflies over the next few months. The testing will take place in a specially designed flight arena at HHMI's Janelia Farm complex equipped with nature scenes on the walls, a pond and plenty of fruit flies for the dragonflies to eat.

The chip, with two hair-thin antennae projecting from the back, will be attached to the belly of the insect so as not to interfere with the wings. Since the chip must have uninterrupted radio contact with the power transmitter on the ground, the chip is carried much like the backup parachute on the underside of the animal.

Libellules à gogo

Dragons galore!

Broad-bodied Chasers:
Libellula depressa:
Odonata, Anisoptera

Un mâle de Libellule déprimée, tout juste adulte, se rapproche tranquillement de l'étang:

A young male gets closer to the lake:

Un autre mâle autour de l'eau attend le passage d'une dame pour la "kidnapper"! Il n'est pas tout seul, des Agrions Porte-coupe en tandem se sont installés sur les tiges mortes des joncs qui retombent vers l'eau, formant un support idéal:

Dans le jardin, celui-ci tourne toujours autour de la piscine pourtant encore couverte... peut-être toujours le même que celui-ci!!

Orthetrum réticulé: une femelle grignote et prend des forces pour aller pondre!

Black-tailed Skimmer female eating a bug:

Orthetrum cancellatum:

Noushka

Orthétrum réticulé

Orthetrum cancellatum

Black-tailed Skimmer

Photos prises avec Alain et Colette, récupérées en même temps que celles de Crocothémis sur ma carte d'APN!

Un vieux mâle guette une dame:
A male waiting for the opportunity to seize a female:

05 septembre 2010

Celle-ci est trop occupée à me faire des clowneries:
Female:

Mais finalement accepte les avances du sieur:
In copula:

Noushka

Orthétrum réticulé, un tandem!

I usually get pictures of those Black-lined Skimmers in a heart formation, the "copulatory heart", but this is my first tandem with them !

J'avais déjà pris des O. cancellatum en coeur copulatoire, mais jamais en tandem! Voilà, c'est chose faite! Ces radins ne m'ont laissé prendre qu'une seule photo... elle est loin d'être parfaite, mais bon, je suis contente!

The female shows a certain degree of colour-loss but is still laying actively. Their flight span does not exceed 40 days! The female below is resting safe and motionless to pass unnoticed by males eager to grab her for mating!
La femelle est vieillissante et a besoin de se reposer après la ponte tout en tentant d'échapper à son mâle ainsi qu'aux autres mâles acharnés à kidnapper toute femelle qui passe! Elle a déjà perdu ses belles couleurs: la période de vol d'une libellule est à peu de chose près 40 jours... C'est court, elle doit se dépêcher! :)

Noushka

Orthétrums, j'appelle ces dames!

Orthetrum albistylum

Female Skimmers
White-Tailed Skimmer newly emerged, on the ground and in the middle of the path... I show here the colour evolution of these females as they emerge from the water.

Orthetrum à stylets blancs

Une toute jeune fille a émergé très tôt ce matin-là... Elle est encore accrochée à son exuvie! Elles sont alors d'un beige très pâle et leurs ailes ressemblent à de la fine dentelle en papier plastifié! Heureusement sinon j'aurais pu marcher dessus sans la voir! Je l'ai trouvée au raz du sol au milieu du chemin, ce qui est assez inhabituel, mais à sa sortie de l'étang elle n'a pas dû trouver de branches ni d'arbustes proches de l'eau.

Premier petit vol, elle se perche à ma hauteur et sur un petit fruit rouge, chic !!

This one is slightly more mature:
Une autre, un peu plus âgée commence à prendre ses couleurs...



Orthetrum cancellatum:
Young Black-lined Skimmers:
Orthétrum réticulé, jeunes femelles plus jaunes que O. abistylum, les stylets sont noirs:

Noushka

Une bien belle matinée!

A beautiful morning!

Anax imperator:

J'avais remarqué le manège de cet Anax qui s'est posté à 3 reprises sur cette branche alors que j'arrivais à l'étang... Profitant de son absence, je me suis installée dans les joncs, devant son poste! Et voilà!
I had noticed how this emperor dragonfly came back regularly to this branch so I crept into the rush facing it and 10 minutes later, it was back to its resting spot!

Orthetrum cancellatum:
Black-lined Skimmer:Le soleil atteint enfin l'ensemble du point d'eau et cette femelle Orthétrum réticulé est venue se reposer devant moi... J'étais alors cachée à l'ombre d'un chêne!


Onychogomphus forcipatus:
Small Pincertail:

Et voici mon premier Onychogomphe à pinces, plus rare chez moi qu'O. uncatus. Ces libellules se rapprochent de l'étang... Des yeux bien verts!


Noushka