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Earth Science

Dung Beetles Navigate By the Milky Way; Pigeons Tune In To Magnetism 82

sciencehabit writes with this excerpt from Science magazine's colorful synopsis of a paywalled article at Current Biology "A day in the life of a male dung beetle goes something like this: Fly to a heap of dung, sculpt a clump of it into a large ball, then roll the ball away from the pile as fast as possible. However, it turns out that the beetles, who work at night, need some sort of compass to prevent them from rolling around in circles. New research suggests that the insects use starlight to guide their way. Birds, seals, and humans also use starlight to navigate, but this is the first time it's been shown in an insect." Also on the topic of How Animals Get Around Without GPS, new research has considerably heightened scientists understanding of birds' sensitivity to magnetic fields. For homing pigeons at least, this ability seems to be tied to a cluster of just 53 neurons (original paper, also behind a paywall).
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Dung Beetles Navigate By the Milky Way; Pigeons Tune In To Magnetism

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  • by girlinatrainingbra ( 2738457 ) on Sunday January 27, 2013 @12:06AM (#42705385)
    It's been hypothesized that pigeons also use polarized light [wikipedia.org] to sense the position of the sun in the sky-sphere, even if the sun itself is obscured from direct viewing. It's been definitely shown to be true for:
    -- honeybees : http://en.wikipedia.org/wiki/Animal_navigation#Orientation_by_polarised_light [wikipedia.org]
    -- squids eyes : http://en.wikipedia.org/wiki/Cephalopod_eye#Polarized_light [wikipedia.org]
    -- fishies : http://en.wikipedia.org/wiki/Vision_in_fishes#Polarized_light [wikipedia.org]
    Pigeons have been tested for polarization sensing and magnetic field sensing by William Tinsley Keeton [wikipedia.org].
  • by Xeno man ( 1614779 ) on Sunday January 27, 2013 @12:54AM (#42705541)

    You dont have to be able to prove anything. You can just make up something and as long as it sounds good then youre a scientist. Hell you can be a good speaker and call yourself a scientist, if you can phrase and word things in a good way you can make up crazy stuff you have no idea about and people will believe you because there is no way to prove that youre wrong. And thats what a lot of "science" is, its saying something that sounds good while at the same not being able to be proved wrong.

    "A dung beetle navigtes via the milky way" how you can you possibly prove that to be false?

    Obviously you didn't get past the summary, or maybe even the title but what you claim is not science. Science is not spouting random things and waiting for someone else to prove you wrong. Go try that and you will have the credibility of the guy shouting that the end is near. Findings are whats published with procedures and methods used to reach those findings. Others interested can reproduce the experiment to try to get the same results to try to confirm those findings. If they can't reproduce the same results then the original finding must be declared false and reevaluated.

    What you think of science is the result of journalists taking the findings and dumbing them down enough so people like you can understand a new fact.

  • by SternisheFan ( 2529412 ) on Sunday January 27, 2013 @02:00AM (#42705737)
    Ok, then there are other links to this...

    http://www.wired.com/wiredscience/2013/01/dung-beetle-astronomy/ [wired.com]

    http://www.bbc.co.uk/news/science-environment-21150721 [bbc.co.uk]

    http://www.cell.com/current-biology/retrieve/pii/S0960982212015072 [cell.com]

    African dung beetles orient to the starry sky to move along straight paths The beetles do not orientate to the individual stars, but to the Milky Way Summary When the moon is absent from the night sky, stars remain as celestial visual cues. Nonetheless, only birds [1,2], seals [3], and humans [4] are known to use stars for orientation. African ball-rolling dung beetles exploit the sun, the moon, and the celestial polarization pattern to move along straight paths, away from the intense competition at the dung pile [5,6,7,8,9]. Even on clear moonless nights, many beetles still manage to orientate along straight paths [5]. This led us to hypothesize that dung beetles exploit the starry sky for orientation, a feat that has, to our knowledge, never been demonstrated in an insect. Here, we show that dung beetles transport their dung balls along straight paths under a starlit sky but lose this ability under overcast conditions. In a planetarium, the beetles orientate equally well when rolling under a full starlit sky as when only the Milky Way is present. The use of this bidirectional celestial cue for orientation has been proposed for vertebrates [10], spiders [11], and insects [5,12], but never proven. This finding represents the first convincing demonstration for the use of the starry sky for orientation in insects and provides the first documented use of the Milky Way for orientation in the animal kingdom.

    http://www.cell.com/current-biology/retrieve/pii/S0960982212015072 [cell.com]

  • by docmordin ( 2654319 ) on Sunday January 27, 2013 @02:05AM (#42705757)

    Most, if not all authors, will be more than happy to send you the final copy of the manuscript if you email them, even if you aren't affiliated with a university or a researcher yet want still to learn about their work. In the case of old papers that can't be found on the Internet, which is common for some math journals that are no longer in print, I've found authors to be especially accommodating in sending hard copies.

  • by SternisheFan ( 2529412 ) on Sunday January 27, 2013 @08:31AM (#42706617)
    Dung beetle; Ecology and behavior:

    Dung beetles live in many different habitats, including desert, farmland, forest, and grasslands. They do not prefer extremely cold or dry weather. They are found on all continents except Antarctica.

    Dung beetles eat dung excreted by herbivores and omnivores, and prefer that produced by the former. Many of them also feed on mushrooms and decaying leaves and fruits. One type living in Central America, Deltochilum valgum, is a carnivore preying upon millipedes. Those that eat dung do not need to eat or drink anything else, because the dung provides all the necessary nutrients.

    Most dung beetles search for dung using their sensitive sense of smell. Some of the smaller species simply attach themselves to the dung-providers to wait for their reward. After capturing the dung, a dung beetle will roll it, following a straight line despite all obstacles. Sometimes dung beetles will try to steal the dung ball from another beetle, so the dung beetles have to move rapidly away from a dung pile once they have rolled their ball to prevent it from being stolen. Dung beetles can roll up to 10 times their weight. Male Onthophagus taurus beetles can pull 1,141 times their own body weight: the equivalent of an average person pulling six double-decker buses full of people. In 2003, researchers found one species of dung beetle (the African Scarabaeus zambesianus) navigates by using polarization patterns in moonlight. The discovery is the first proof any animal can use polarized moonlight for orientation. In 2013 a study was published revealing that dung beetles can navigate when only the Milky Way or clusters of bright stars are visible, the only animal known to orient themselves with the galaxy.

    The "rollers" roll and bury a dung ball either for food storage or for making a brooding ball. In the latter case, two beetles, one male and one female, will be seen around the dung ball during the rolling process. Usually it is the male that rolls the ball, with the female hitch-hiking or simply following behind. In some cases the male and the female roll together. When a spot with soft soil is found, they stop and bury the dung ball. They will then mate underground. After the mating, both or one of them will prepare the brooding ball. When the ball is finished, the female lays eggs inside it, a form of mass provisioning. Some species do not leave after this stage, but remain to safeguard their offspring.

    The dung beetle goes through a complete metamorphosis. The larvae live in brood balls made with dung prepared by their parents. During the larval stage, the beetle feeds on the dung surrounding it.

    The behavior of the beetles was much misunderstood until the pioneering studies of Jean Henri Fabre. For example, Fabre corrected the myth that a dung beetle would seek aid from other dung beetles when confronted by obstacles. By painstaking observations and experiments, he found the seeming helpers were, in fact, robbers awaiting an opportunity to steal the roller's food source:

    “I ask myself in vain what Proudhon introduced into Scarabaean morality the daring paradox that "property means plunder", or what diplomatist taught the Dung-beetle the savage maxim that "might is right".

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

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