Riddle Me This, How Do They Know?

Discussion in 'Warm Water Species' started by GAT, Feb 15, 2013.

  1. A Toxic Salamander
    Western Newt is the vernacular name for the genus Taricha of which there are three species: torosa, granulosa, and rivularus. These are toxic salamanders found exclusively in particular regions of California, the western halves of Oregon and Washington, and western costal Canada up through parts of Alaska (3).




    Okay, so bass eat salamanders, but not all. In the case of the "mud puppies", they are poisonous to bass so the LMB avoid them. How do the bass know what they are not supposed to eat? I guess it must be genetic and not taught... otherwise, some poor, dumb bass would end up eating the deadly salamander and the other bass would take notice.

    "Whoa! What happened to Charlie?"

    "I think he's dead. Guess we shouldn't eat those odd colored salamanders"

    "Good tip."

    Evidently it must be inborn and not taught... but only for LMB where the salamanders are poisonous.

    Strange when you think about it.
     
  2. Gene, You have too much time on your hands. :) You need to string up a rod and get out there and shake off the cobwebs. A couple of casts and it will all come back to you. You'll be allright.

    Ive
     
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  3. Hi Gene,
    One of my recent research foci has been on chemical defense. While there are some cases where the defense causes death at some later point, typically, these just make the predator sick when they bite the defended prey. In the case of plants, typically just part of the plant is eaten and the predators learn to avoid it, either by color or odor. If the defended organism is an animal partial predation (i.e., a bite ingested) is less likely and more commonly the chemical defense is excreted from surface glands. This usually leads to immediate rejection by the predator and the prey survives (e.g., beak marks on the wings of defended butterflies like Monarchs). Many chemically-defended organisms have distinctive colorations (aposematic coloration). This has lead other defended species to converge on the same patterns (Mullerian mimicry) or for undefended species to evolve the coloration of the defended species and mooch off the defensive chemistry of the defended species (Batesian mimicry, e.g., edible Viceroy butterflies have a similar coloration to defended Monarch butterflies).

    In my research with sculpins, often naive fish spit out the chemically-defended amphipods immediately (and the amphipods survive just fine); in other cases, the amphipods end up in the fish's stomach but the amphipods are regurgitated a few minutes later and these amphipods often survive too. It only takes a few exposures before the predators learn to recognize and ignore these chemically-defended prey.

    The common garter snake, Thamnophis sirtalis, has evolved to be unaffected by the tetradotoxin (similar to the toxin synthesized by the fugu pufferfish) that Taricha secrete through their skin glands. It is considered a classic case of an evolutionary arms race between predators and prey.

    Steve
     
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  4. Great stuff, Steve, didn't realize tetradotxin similarity.
     
  5. Hi Upton,
    Your comment stirred me to dig further into the common link among the species that produce tetradoxin. After all, pufferfish and newts don't really have a close common ancestor and that type of molecular convergence would be rare. The prevailing hypothesis (with some lose ends outstanding) is that the toxin is actually produced by symbiotic Vibrio bacteria (see http://en.wikipedia.org/wiki/Tetrodotoxin). Other species that have tetradotoxin include blue-ringed octopus, some flatworms, crabs, nemertean worms, and angelfish among others. Quite a diverse group.

    Tetradoxin works by blocking electrical signals that are carried along the surface membranes of nerve and muscle cells. No signals = death.

    Steve
     
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  6. Next weekend... weather permitting. I don't do rain and wind these days. Besides, I'm always questioning why, when and where when it comes to flyfishing.
     
  7. Some interesting stuff here. Never thought about the issue until now.

    Another thought is that perhaps there is an underwater network that
    post threads about what to eat and what not to eat. Or could it be that some LMB swim with sandwich boards that proclaim DO NOT EAT THE SALAMANDERS!
     
  8. Charlie, I'm leaning more toward your explination. ....:D

    ....if you ask me, that's a damned poor defense system ... don't eat me because if you do, you'll die... of course I'm dead too...
     
  9. Why else would fish be found in schools? It's pretty hard to give clear instructions over long distances underwater. Sheesh.
     
  10. Hmmmmmmmmmm.... there may be a cartoon somewhere in all this.
     
  11. Hahahaha. I think you are correct Gene.
     
  12. Read something on another forum about birds having toxin defenses...be careful what birds/feathers you're tying with.
     
  13. I no longer worry about toxic feathers once I started wearing latex gloves while tying flies....:)
     
  14. I think Bass are too dumb to know that certain salamanders are toxic. I think some bass eat them and die. We don't see them because they are laying dead on the bottom and serve as food for other organisms. There are probably not enough salamanders for bass too eat to reduce the bass populations.
     
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