Slashdot Mirror

← Back to Stories (view on slashdot.org)

Ocean-Crossing Dragonflies Discovered

Posted by samzenpus on 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."

70 of 95 comments (clear)

  1. Maldives by spyder-implee · · Score: 3, Insightful

    I can think of worse places to study :)

    --
    Take what ye can. Give nothing back!
  2. Impressive... by fuzzyfuzzyfungus · · Score: 4, Insightful

    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.

    1. Re:Impressive... by TheGratefulNet · · Score: 4, Funny

      ...or ability to harness solar energy ;)

      --

      --
      "It is now safe to switch off your computer."
    2. Re:Impressive... by wizardforce · · Score: 4, Informative

      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.

      --
      Sigs are too short to say anything truly profound so read the above post instead.
    3. Re:Impressive... by Nefarious+Wheel · · Score: 1

      Their flight speed is up to 5 m / s.

      Would that be laden or unladen?

      --
      Do not mock my vision of impractical footwear
    4. Re:Impressive... by tirerim · · Score: 3, Informative

      Uh, that would be about 1.5 days—there are 86,400 seconds in a day. That's assuming that they maintain their maximum flight speed the whole time, of course.

    5. Re:Impressive... by MichaelSmith · · Score: 1

      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.

      --
      http://michaelsmith.id.au
    6. Re:Impressive... by criminy · · Score: 5, Funny

      400 miles is about 640,000 meters

      640k should be enough for anyone.

    7. Re:Impressive... by Anonymous Coward · · Score: 1, Funny

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

    8. Re:Impressive... by edman007 · · Score: 5, Informative

      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.

    9. Re:Impressive... by __aaqvdr516 · · Score: 1

      Where'd you get those coconuts?

    10. Re:Impressive... by Insanity+Defense · · Score: 1

      Uh, that would be about 1.5 days—there are 86,400 seconds in a day. That's assuming that they maintain their maximum flight speed the whole time, of course.

      I believe you made a typo. That should be closer to 7.5 days. Assuming maximum speed and no diversions from the direct path.

    11. Re:Impressive... by RuBLed · · Score: 5, Funny

      It can be explained, consider a spherical dragonfly in a vacuum...

    12. Re:Impressive... by MichaelSmith · · Score: 3, Interesting

      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.

      --
      http://michaelsmith.id.au
    13. Re:Impressive... by oldhack · · Score: 2, Interesting

      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?

      --
      Fuck systemd. Fuck Redhat. Fuck Soylent, too. Wait, scratch the last one.
    14. Re:Impressive... by CrazyTerabyte · · Score: 1

      It depends on how many dragonflies it takes to feed those birds who tag along.

    15. Re:Impressive... by arose · · Score: 1

      Then again the maximum speed is almost certainly measured without any wind.

      --
      Analogies don't equal equalities, they are merely somewhat analogous.
    16. Re:Impressive... by bmecoli · · Score: 1

      Wouldn't that make them some sort of hybrid plant then? ;p

    17. Re:Impressive... by EdIII · · Score: 1

      Man, you are really *working hard* for that +5 Funny aren't you?

    18. Re:Impressive... by zoewhite · · Score: 1

      1.5days.

    19. Re:Impressive... by judugrovee · · Score: 1

      Uh, that would be about 1.5 days—there are 86,400 seconds in a day. That's assuming that they maintain their maximum flight speed the whole time, of course.

      Is that for an American or an East-African Globe Skimmer? ...just wanted to know...

    20. Re:Impressive... by cowboy76Spain · · Score: 4, Insightful

      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.

      --
      Why can't /. have a rich-text editor? Editing your own HTML is so XXth century.
    21. Re:Impressive... by SoupIsGoodFood_42 · · Score: 1

      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.

    22. Re:Impressive... by MichaelSmith · · Score: 1

      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.

      --
      http://michaelsmith.id.au
    23. Re:Impressive... by osu-neko · · Score: 2, Informative

      Then again the maximum speed is almost certainly measured without any wind.

      Or rather, it's an airspeed, which is measured relative to the surrounding air, and is thus unaffected by wind speed. Your speed relative to the ground can be greatly affected by wind, but your airspeed tends to be the same regardless of the wind.

      --
      "Convictions are more dangerous enemies of truth than lies."
    24. Re:Impressive... by AndGodSed · · Score: 1

      Is that sustained speed or burst speed? I heard (way back in my youth in Biology class or... somewhere) that they reach these speeds in short bursts or when changing direction.

      --

      Seven Days with Ubuntu Unity

    25. Re:Impressive... by jonadab · · Score: 1

      > 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 generally be a rather greater distance (multiple thousands of miles).

      --
      Cut that out, or I will ship you to Norilsk in a box.
    26. Re:Impressive... by jc79 · · Score: 1

      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, which annually migrates from Siberia to Southern Africa.

    27. Re:Impressive... by TheLink · · Score: 1

      Very impressive.

      My toy helis can only fly for about 6-8 minutes, and they need me around to control them.

      Whereas here we have something that can autonomously fly 400 miles over the ocean from place to place, and probably flying for days. Something that can navigate, find+catch food, reproduce etc.

      Our tech is still very behind in so many ways.

      --
    28. Re:Impressive... by sznupi · · Score: 2, Interesting

      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 become stationary in relation to the prey, its eyes.

      I expect dragonflies can still surprise when it comes to their flying capabilities. They were perfecting it (active predators and all...) since before there were dinosaurs.

      --
      One that hath name thou can not otter
    29. Re:Impressive... by Oligonicella · · Score: 3, Informative

      They can do 30mph pretty much all day. They are the most efficient flier amongst the insects.

    30. Re:Impressive... by CaptSlaq · · Score: 1
      There's an XKCD reference here....

      Experiment

    31. Re:Impressive... by rident · · Score: 1

      Maybe we should harness them! :P

    32. Re:Impressive... by HTH+NE1 · · Score: 1

      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.

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

      --
      Oh, say does that Star-Spangled Banner entwine / The myrtle of Venus with Bacchus's vine?
    33. Re:Impressive... by evilviper · · Score: 1

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

      "Bug bomb malfunction, Thodin."

      Too obscure? ...even for /. ?

      --
      Slashdot gets worse every day... Pipedot: News for nerds, without the corporate slant
  3. TED by Anonymous Coward · · Score: 4, Informative

    http://www.ted.com/talks/charles_anderson_discovers_dragonflies_that_cross_oceans.html

  4. Name by treeves · · Score: 4, Insightful

    Was it called the Globe Skimmer before his discovery? If so, it was quite a prescient name.

    --
    ...the future crusty old bastards are already drinking the Kool-Aid.
    1. Re:Name by courseofhumanevents · · Score: 5, Funny

      I don't think it was called anything before it was discovered, actually.

    2. Re:Name by Tablizer · · Score: 3, Funny

      "Ralph"

      --
      Table-ized A.I.
    3. Re:Name by Anonymous Coward · · Score: 2, Insightful

      ... before HIS discovery...

      As in the discovery that it flew so far.

    4. Re:Name by edman007 · · Score: 5, Informative

      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

      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.

    5. Re:Name by oldhack · · Score: 1

      Coulda been called UFO.

      --
      Fuck systemd. Fuck Redhat. Fuck Soylent, too. Wait, scratch the last one.
  5. Wow! Only one question comes to mind by Anonymous Coward · · Score: 3, Funny

    How many would it take to carry a coconut?

    1. Re:Wow! Only one question comes to mind by Insanity+Defense · · Score: 1

      How many would it take to carry a coconut?

      How many dragonflies to get the coconut away from the octopus?

    2. Re:Wow! Only one question comes to mind by An+ominous+Cow+art · · Score: 1

      One thing is certain: there's no stopping them. The dragonflies will soon be here. And I, for one, welcome our new insect overlords.

    3. Re:Wow! Only one question comes to mind by toastar · · Score: 1

      That depends Is it african or indian?

    4. Re:Wow! Only one question comes to mind by jaiger · · Score: 1

      Does it blend?

  6. He will be a secret dragonfly by Anonymous Coward · · Score: 1

    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 secret dragonfly
    Fly dragon fly, here from the sky
    So if you hear that sound I'm talkin' about
    When you know he's near
    When your times run out
    Well don't you fear
    There's nothing that you can say
    Cause he'll appear and take you to that special place
    He'll take you there

    1. Re:He will be a secret dragonfly by Trepidity · · Score: 1

      If we're going to do dragonfly songs, how about this one from DDR.

      --
      10 PRINT CHR$(205.5+RND(1)); : GOTO 10
    2. Re:He will be a secret dragonfly by Aaron32 · · Score: 1

      I read that to the tune of "The Ballad of Jed Clampett". Amazingly it fits!

  7. Re:gaaah, link to a fucking video by SECProto · · Score: 1

    Because wanting to read instead of watching video is exactly what was portrayed in that film...

  8. Re:gaaah, link to a fucking video by HouseOfMisterE · · Score: 3, Funny

    ...It's a PITA for me to watch videos...

    Leave the toys put away when watching p0rn! That will help.

  9. They've always been ocean crossing... by tompaulco · · Score: 4, Funny

    ...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.

    --
    If you are not allowed to question your government then the government has answered your question.
    1. Re:They've always been ocean crossing... by AtomicSnarl · · Score: 1

      The second attempt caught fire, fell over, and sank into the swamp. The third attempt was more successful!

      --
      Pacifist paratroopers yell, "Ghandi!" when they jump.
  10. Re:gaaah, link to a fucking video by TapeCutter · · Score: 1

    "but a fucking video can go for hours"

    20 minutes tops without viagra.

    --
    And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
  11. How bout them locust? by icegreentea · · Score: 2, Interesting

    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

    1. Re:How bout them locust? by Group+XVII · · Score: 1

      Here's a link to Lovejoy et al., Ancient Trans-Atlantic Flight Explains Locust Biogeography.

    2. Re:How bout them locust? by BigBlueOx · · Score: 1

      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 flamethrowers and we whipped the whole thing out for $12,000 cos the actors only have 5 lines each and only had to stand in front of a green-screen for 15 minutes.

      You'll watch it anyway. You'll watch anything.

  12. Slashdot slowing down? by brajbir · · Score: 1

    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?

    1. Re:Slashdot slowing down? by John+Hasler · · Score: 1

      "Months ago"? That's pretty quick for Slashdot, actually.

      --
      Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
  13. Re:gaaah, link to a fucking video by twitcher101 · · Score: 1

    If you read the link (you should always do this, do you just trust all sources on the net? If you do, boy oh boy have I got some links for you), you can see it is a link to a TED talk, thus a video. No need to complain about your own poor clicking habits.

    --
    Time is an illusion, lunchtime doubly so- Zaphod beeblebrox
  14. Re:This is a first for marine biology by jimbobborg · · Score: 1

    He used a boat?

  15. Re:gaaah, link to a fucking video by StalinsNotDead · · Score: 1

    Any longer than 4 hours and you're supposed to see a doctor.

    --
    Thanks to the internet, we can now all die alone together! -SomeWoman
  16. Re:gaaah, link to a fucking video by Abstrackt · · Score: 1

    ...It's a PITA for me to watch videos...

    Leave the toys put away when watching p0rn! That will help.

    I didn't hear him complaining. ;)

    --
    They say a little knowledge is a dangerous thing, but it's not one half so bad as a lot of ignorance. - Terry Pratchett
  17. Re:Who crosses who how? by grikdog · · Score: 1

    "I'm not a grammer nazi..." G-R-A-M-M-A-R. Sorry.

    --
    ``Tension, apprehension & dissension have begun!'' - Duffy Wyg&, in Alfred Bester's _The Demolished Man_
  18. Re:gaaah, link to a fucking video by socsoc · · Score: 1

    I agree with you, there was no real article. It wasted my time clicking on the link because I wanted to skim an article, not watch someone um and ah for awhile. A video tag would be useful.

  19. Coconuts by xupere · · Score: 1

    Were they African or European dragonflies?

  20. Re:Who crosses who how? by orngjce223 · · Score: 1

    No, you are a grammar nazi. Just not a spelling nazi.

    --
    Note: I was 13 when I wrote most of this. Take with several grains of salt.
  21. Flying Debugger? by sergiol · · Score: 1

    I did not know that Opera debugger could open wings and go from Europe to America by air and catch some bugs on there.

  22. the letters in TFA are hilarious by vaporland · · Score: 1

    comments about never using the typeface Papyrus - which, indeed, is a hideous font... and used in the banner of the webpage of TFA...

    --
    Ask Me About... The 80's!