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Ocean-Crossing Dragonflies Discovered 95

Posted by samzenpus
from the incredible-journey dept.
grrlscientist writes "While living and working as a marine biologist in Maldives, Charles Anderson noticed sudden explosions of dragonflies at certain times of year. He explains how he carefully tracked the path of a plain, little dragonfly called the Globe Skimmer, Pantala flavescens, only to discover that it had the longest migratory journey of any insect in the world."
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Ocean-Crossing Dragonflies Discovered

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  • Maldives (Score:3, Insightful)

    by spyder-implee (864295) on Wednesday January 06, 2010 @09:49PM (#30678328)
    I can think of worse places to study :)
  • Impressive... (Score:5, Insightful)

    by fuzzyfuzzyfungus (1223518) on Wednesday January 06, 2010 @09:58PM (#30678410) Journal
    There just isn't much room for energy storage inside a dragonfly. They must have commendably efficient ways of staying in the air, presumably a combination of powered flight and exploitation of available air currents.

    It would be interesting to know what percentage of them survive.
    • by TheGratefulNet (143330) on Wednesday January 06, 2010 @10:08PM (#30678482)

      ...or ability to harness solar energy ;)

    • Re:Impressive... (Score:5, Informative)

      by wizardforce (1005805) on Wednesday January 06, 2010 @10:10PM (#30678492) Journal

      TFA has a video that explains quite a bit about the species and one of the interesting things about it is that the dragonfly cruses at an altitude of 1-2 km over the surface. They migrate in order to catch the rainy season of East Africa and India. The winds at this altitude move toward the rainy areas due to meteorological effects so they do make use of air currents.

      • Maybe the dragonfly can feed on other insects along the way. Also I wondered if it is light enough to sit on the water using surface tension.

        • Re:Impressive... (Score:5, Informative)

          by edman007 (1097925) on Wednesday January 06, 2010 @10:47PM (#30678766)

          When you are small and light it is not actually required that you expel energy to float, the turbulence in the air can keep you going to a very long time for example water can stay in a cloud long enough to become softball sized hail and a glider can stay in the air all day, the energy is technically wind energy derived from solar and it is not coming from the object flying.

          • Re:Impressive... (Score:4, Interesting)

            by MichaelSmith (789609) on Wednesday January 06, 2010 @11:26PM (#30679000) Homepage Journal

            True but at least in the case of the sailplane (or albatross) you need control authority to steer out of sink and into lift which does take energy. In the case of an insect I can't see it having sufficiently low drag to take advantage of lift. To do that you need to be able to put your nose down and fly out of sink sometimes.

            • Re:Impressive... (Score:5, Insightful)

              by cowboy76Spain (815442) on Thursday January 07, 2010 @03:24AM (#30680068)

              Well... they are insects, so their strategy is usually based in numbers. Maybe only 1 in 5 dragonflies (warning, numbers made up) get to end the travel safely; that would be unacceptable for men or other animals that take years to mature but for insects could be reasonable.

              • by evilviper (135110)

                Maybe only 1 in 5 dragonflies (warning, numbers made up) get to end the travel safely;

                "Bug bomb malfunction, Thodin."

                Too obscure? ...even for /. ?

            • In the case of an insect I can't see it having sufficiently low drag to take advantage of lift.

              I don't follow you here. What makes you think a dragonfly has too much drag to be able to gain enough speed to generate lift? Between the lift and the air currents, I can see how it could conserve quite a lot of energy if it knows how to ride the currents.

              • In the case of an insect I can't see it having sufficiently low drag to take advantage of lift.

                I don't follow you here. What makes you think a dragonfly has too much drag to be able to gain enough speed to generate lift? Between the lift and the air currents, I can see how it could conserve quite a lot of energy if it knows how to ride the currents.

                I mean if it finds itself in a body of sink (air going down) it won't be able to fly out into air which is rising (lift) while an albatross would be able to do that because it can fly faster.

            • Re: (Score:3, Interesting)

              by sznupi (719324)

              I seem to remember dragonflies semi-regularly keep one pair of their wings stationary during flight. Perhaps they also sometimes fly with both not-flapping? Certainly there's an airfoil.

              Generally they are highly agile, capable of incredible feats for such simple nervous system - for example, during pursuit of their pray, they supposedly follow a "camouflaging" flightpath; first one which makes them stationary in relation to the scenery, from the point of view of the pray! Afterwards, when closer, they becom

      • Re: (Score:2, Interesting)

        by oldhack (1037484)

        Now here is a science story makes me say "wow".

        Chasing the rain seasons... wonder if they make use of the same seasonal trade wind that kept the ancient maritime trade going around the Indian Ocean?

    • Re: (Score:1, Funny)

      by Anonymous Coward

      Just wondering - how many dragonflies it would take to carry a one pound coconut?

    • by RuBLed (995686) on Wednesday January 06, 2010 @11:19PM (#30678958)
      It can be explained, consider a spherical dragonfly in a vacuum...
    • by jonadab (583620)
      > There just isn't much room for energy storage inside a dragonfly.

      There isn't all that much mass, either.

      > They must have commendably efficient ways of staying in the air,

      I'm sure the ratio of surface area to mass has something to do with it.

      What I want to know is, when we say "Ocean-crossing" here, does he just mean they're flying from India to the Maldives (about 500 miles offshore)? Because the word "crossing" normally implies "from one side to the other", which, when it comes to oceans, would ge
      • by jc79 (1683494)

        What I want to know is, when we say "Ocean-crossing" here, does he just mean they're flying from India to the Maldives (about 500 miles offshore)? Because the word "crossing" normally implies "from one side to the other", which, when it comes to oceans, would generally be a rather greater distance (multiple thousands of miles).

        TFA (extremely interesting video) shows that the dragonflies migrate from India to South East Africa (via the Maldives and Seychelles). In four generations, they chase the rains across the Indian Ocean and back. About 16000km.

        And several species of birds follow them, including the Amur Falcon [wikipedia.org], which annually migrates from Siberia to Southern Africa.

      • by HTH NE1 (675604)

        What I want to know is, when we say "Ocean-crossing" here...

        But we didn't say "ocean-crossing dragonflies" here, we said "ocean crossing dragonflies".

        How do you get an ocean to cross a dragonfly? And how do you get the dragonfly to hold still while it does it?

        It's like that movie about eight freaks with legs [imdb.com].

        (Hint: tags aren't working for everyone.)

  • TED (Score:4, Informative)

    by Anonymous Coward on Wednesday January 06, 2010 @09:58PM (#30678414)
  • Name (Score:5, Insightful)

    by treeves (963993) on Wednesday January 06, 2010 @09:58PM (#30678416) Homepage Journal
    Was it called the Globe Skimmer before his discovery? If so, it was quite a prescient name.
    • Re:Name (Score:5, Funny)

      by courseofhumanevents (1168415) on Wednesday January 06, 2010 @10:06PM (#30678466)
      I don't think it was called anything before it was discovered, actually.
    • Re: (Score:1, Redundant)

      by binarylarry (1338699)

      Yeah, sounds like Captain Obvious better start turning things up a notch.

      He apparently has some serious competition living in Maldives.

    • Re:Name (Score:5, Informative)

      by edman007 (1097925) on Wednesday January 06, 2010 @10:52PM (#30678804)

      According to the wikipedia:

      Pantala flavescens, the Globe Skimmer or Wandering Glider, is a wide-ranging dragonfly of the family Libellulidae. This species and Pantala hymenaea, the "Spot-winged Glider", are the only members of the genus Pantala from the subfamily Pantalinae. It was first described by Fabricius in 1798.[1] It is considered to be the most widespread dragonfly on the planet.

      The English common names "Wandering Glider" and "Globe Skimmer" refer to its migratory behaviour.[3] The German name Wanderlibelle mean "migrant dragonfly". In Hong Kong, its name translates as Typhoon Dragonfly as it arrives with or shortly before the seasonal rain.

      http://en.wikipedia.org/wiki/Globe_Skimmer [wikipedia.org]

      It seems to me that it has been known that it just seems to "show up" at specific times of the year and does migrate, but nobody knew just how far it really did migrate.

  • by Anonymous Coward on Wednesday January 06, 2010 @09:59PM (#30678426)

    How many would it take to carry a coconut?

  • by Anonymous Coward

    Well listen, someday
    You'll hear a rush of wings
    So distant, a sound of secret things
    There, look there, up in that rusty sky
    Yonder, sweeps the dragonfly
    So awesome, he blocks the setting sun
    He'll come to collect the souls of everyone
    Come dragon, come
    In from the sun
    He floats with an eerie grace
    A giant blue green sentinal
    From some distant time and space
    And because he'll come, he'll have no regrets
    Surely he'll come to lay this birth to rest
    I know one day you'll see him
    But please don't ask me why
    He will be a secre

  • by tompaulco (629533) on Wednesday January 06, 2010 @11:02PM (#30678874) Homepage Journal
    ...but up until now the scientific tracking tools were too heavy and the dragonflies all fell into the ocean and drowned. Why, it was only 10 years ago that advances in tracking devices caused scientists to discover that dragonflies could actually fly.
    • The second attempt caught fire, fell over, and sank into the swamp. The third attempt was more successful!
  • by icegreentea (974342) on Thursday January 07, 2010 @12:45AM (#30679428)
    This is really cool stuff. It reminded me of some stuff I read before of locust swarms migrating across the Atlantic from Africa to the Americas. But in that case, evidence (a shit load of dead locust washing onto shore) suggested that locust kept dying and the rest of the swarm ate their corpses for fuel and/or used their dead bodies as 'islands'. Just remember that the largest locust swarms are in the billions and cover hundreds of square kilometers on land...

    Anyhow, here's a linky to a National Geographic article (it also suggests the original American populations of locusts were immigrants from across the ocean).
    http://news.nationalgeographic.com/news/2005/12/1228_051228_locusts.html
    • Here's a link to Lovejoy et al. [nih.gov], Ancient Trans-Atlantic Flight Explains Locust Biogeography.
    • If you're interested in a dramatization of invading deadly ocean-crossing locust swarms, and I know you are, I would like to point out that my made-for-SyFy movie "Death Cloud Of Destruction" starring Corin Nemec, Randy Quaid and Random Bimbo will be aired on SyFy this spring. This blockbuster drama will explore the human drama of ordinary people caught in ...

      Ok, be fair, it's all about CGI locusts destroying CGI office buildings while people run around screaming and has lots of kewel explosions and flame
  • I saw this video on TED a couple of weeks ago (I don't visit TED regularly). My guess is that it would have been presented in TED India conference, which was months ago. Is slashdot getting sluggish?
  • Were they African or European dragonflies?
  • I did not know that Opera debugger [opera.com] could open wings and go from Europe to America by air and catch some bugs on there.
  • comments about never using the typeface Papyrus - which, indeed, is a hideous font... and used in the banner of the webpage of TFA...

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