New stuff in Science

Science isn’t really known for publishing a lot of work on organismal or evolutionary biology (Nature is much better at that), but there are two nice papers in the latest issue:

“Tiger Moth Jams Bat Sonar”. This is the punchiest title of a scientific paper I’ve seen in years: not a word longer than five letters.

The tiger moth (Bertholdia trigona) makes a clicking sound when it’s being chased by bats.  There are three possible reasons for this.  First, it could be an “aposematic” call, warning the bats that the moth is distasteful, so that they’ll avoid it after one or more noxious encounters (this would be the equivalent of a rattlesnake’s rattle, or the bright warning coloration of the distasteful ladybug).  This doesn’t seem likely because tiger moths seem to be palatable to bats. Second, the clicks could startle a naive bat and cause it to miss.  Finally, the click could be a “jamming” call, messing up the bat’s sonar so that it can’t locate the moth.  These three hypotheses (which of course are not mutually exclusive) make different predictions about how a bat will behave upon initial and subsequent encounters with a moth. Under the “startle” hypothesis, for example, bats should initially miss the moths but then start catching them as they grow accustomed to the clicks.

The authors  evaluated these hypotheses by presenting tiger moths to naive big brown bats (Eptesicus fuscus). They found that the bat’s behavior best conforms to #3: bats can’t seem to find the moths from the very outset. And the sonic profile of the moth calls is also that expected if they have a “jamming” function.

Bats evolved sonar; tiger moths evolved a jamming call. This is an example of an “arms race”: the perpetual evolution and co-evolution of predators and prey.  According to Richard Dawkins and others, such arms races were a major evolutionary cause of increased biological complexity.

Lizard swims through sand (also reported in The New York Times). The desert-dwelling sandfish lizard (Scincus scincus, found in Africa and the Middle East) not only walks on the sand, but swims through it at speeds of up to 6 inches per second. The ability to dive into the sand and “swim” is useful for escaping the desert heat and evading predators.

Using X-ray cinematography, scientists found that, when swimming undersand, the sandfish retracts its limbs, pressing them against its body, and undulates like an eel, “swimming” through the sand.  This is an efficient way of moving because sand has both liquid- and solid-like properties.

From the “Supplementary material,” three movies of the sandfish:

Burying itself in the sand

Swimming in the sand (an X-ray video, really cool)

Swimming in the sand with opaque markers on the body (shows that its limbs are pressed against the body during the undulatory swimming). The “I-L distance” is the inter-limb distance measured between markers on the limbs; it’s an index of whether the legs are splayed or appressed to the body.

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Tiger Moth Jams Bat Sonar. Aaron J. Corcoran, Jesse R. Barber, and William E. Conner. Science 325:325-327.

Undulatory Swimming in Sand: Subsurface Locomotion of the Sandfish Lizard. Ryan D. Maladen, Yang Ding, Chen Li, Daniel I. Goldman. Science 325:3124-318.

New  stuff

10 Comments

  1. Sili
    Posted July 18, 2009 at 1:10 pm | Permalink

    Apropos of nothing: “skinke” in Danish means “ham”.

  2. Matthew Cobb
    Posted July 18, 2009 at 1:14 pm | Permalink

    The X-ray video is brilliant. And would make a great YouTube mash-up with “Poker Face” by Lady Gaga (try it!)

  3. AdamK
    Posted July 18, 2009 at 3:17 pm | Permalink

    But do they make the spice?

  4. newenglandbob
    Posted July 18, 2009 at 3:30 pm | Permalink

    1. I will conduct an experiment: I will try clicking as I drive down the highway at 80+ MPH and see if I can become invisible to radar.

    2. What an amazing coincidence: a lizard known as sandfish is found to swim through sand after using Using X-ray cinematography.

    /wiseass

  5. Hempenstein
    Posted July 19, 2009 at 7:32 am | Permalink

    NPR covered the moth a couple days ago too.

  6. Posted July 19, 2009 at 9:06 am | Permalink

    Tiger Moth Jams Bat Sonar –

    could be a nice blurb for an evening at the jazz club.

  7. articulett
    Posted July 19, 2009 at 2:58 pm | Permalink

    Science Friday has the moth jam… http://cdn2.libsyn.com/sciencefriday/mothjam-071709.mp4

    To me, they sound like bug zappers…

  8. Posted July 20, 2009 at 3:46 am | Permalink

    Re: lizard swimming. Could it be a good model for snake evolution? If you’re always undersand, you don’t need limbs.

    Marco

  9. KP
    Posted July 20, 2009 at 3:30 pm | Permalink

    “Science isn’t really known for publishing a lot of work on organismal or evolutionary biology (Nature is much better at that), but there are two nice papers in the latest issue”

    Looks like the previous issue had an interesting article too:

    Nagashima et al. 2009. Evolution of the turtle body plan by the folding and creation of new muscle connections. Science 325:193-196 and accompanying “Perspective” on p. 154.

    Appears to be an embryological study of how the rib cage was incorporated into the carapace. Haven’t read yet.

  10. Stacey C.
    Posted July 21, 2009 at 2:33 pm | Permalink

    Hmm…I swear I’ve seen the lizard on an episode of Jeff Corwin. The moth findings are awesome. I love the way organisms develop mechanisms to avoid predation.


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  1. […] There is a lizard that can swim through sand! And yes, there is a moth which has evolved a “click” that foils the sonar of bats (that eat it). […]

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