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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."

24 of 95 comments (clear)

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

    I can think of worse places to study :)

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  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 ;)

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    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.

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    3. 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.

    4. Re:Impressive... by criminy · · Score: 5, Funny

      400 miles is about 640,000 meters

      640k should be enough for anyone.

    5. 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.

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

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

    7. 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.

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    8. 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?

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    9. 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.

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    10. 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.

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    11. 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.

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    12. Re:Impressive... by Oligonicella · · Score: 3, Informative

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

  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.

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    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"

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      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. Wow! Only one question comes to mind by Anonymous Coward · · Score: 3, Funny

    How many would it take to carry a coconut?

  6. 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.

  7. 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.

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  8. 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