Re: RE: NANFA-L-- Michigan Chapter

dlmcneely-in-lunet.edu
Tue, 15 Feb 2005 14:09:36 -0600

J.W., do you know of any studies that suggest that bass respond in this way -- ie., that there are differential responses to madtom envenomation such that some individual bass drop the prey, and that others eat the prey and then go looking for another of the same? And do we actually have data that support a hypothesis that fish feeding is mediated through "thinking" of the sort that you mention?

Fish predatation and behaviors related to it have been extensively studied, but I have never seen any data suggesting this behavior in bass toward madtoms. A good many species of fishes include individual prey specialists, which is a matter of learning, so I suppose it is possible that some bass are madtom specialists; smallmouths do eat them. I would predict, however, that they are eaten in proportion to their availability to bass, or perhaps somewhat less frequently. Determining availability is a tricky thing. Usually, the closest we can come to it is to determine relative abundance of prey.

But the point about evolution is well taken. I will investigate to see if I can find any data in the literature that suggest an immunity to madtom venom in bass.

David L. McNeely, Ph.D., Professor of Biology
Langston University; P.O. Box 1500
Langston, OK 73050; email: dlmcneely-in-lunet.edu
telephone: (405) 466-6025; fax: 405) 466-3307
home page http://www.lunet.edu/mcneely/index.htm

"Where are we going?" "I don't know, are we there yet?"

----- Original Message -----
From: jlw-in-dune.net
Date: Tuesday, February 15, 2005 1:30 pm
Subject: RE: NANFA-L-- Michigan Chapter

> Don't forget also, that predators develop defenses against their
> prey'sdefenses. In other words, they can evolve to be list
> effected by venom, or its
> method of injection. Certainly individuals-in-any given time are
> going to be
> more effected than others -- we can see this even in human beings.
> I love hot
> peppers, and make a plate of chili that makes my S. O. want to
> leave the house
> (we'll pretend it's the CHILI that does that). Yet, I have a
> friend who thinks
> its "Not bad, a little weak."
>
> Fish are the same way -- one bass grabs a madtom and it's like a
> platefull of
> hot peppers. Another grabs one, thinks, "SPICY!" and heads off in
> search of
> another. :)
>
> JW.
>
> Quoting Christopher Gutmann <cgutmann-in-dupageforest.com>:
>
> > It is indeed a defensive mechanism in madtoms. Studies have
> demonstrated> that the venom causes temporary paralysis in some
> predatory fishes. In order
> > for the venom to be released, the integument around the spines
> needs to be
> > broken. In other words, an individual needs to suffer physical
> damage (i.e.,
> > be attacked) for the venom to be released. In pilot studies
> that I conducted
> > years ago, I observed madtoms frequently surviving attacks. As
> soon as the
> > predators were envenomated, they quickly spit out the madtom.
> Furthermore,> the predators in the study refrained from subsequent
> attacks on madtoms
> > during the trials. This, of course, may not be a universal
> response with all
> > predators, but it illustrates that madtoms can survive attacks
> from some
> > predators. Could the venom serve other purposes? Most
> certainly. However,
> > the delivery mechanism and the nature of the venom imply that it
> likely> evolved as an antipredatory response.
> >
> > Chris Gutmann
> > Des Plaines River drainage
> > Oak Brook, Illinois
> >
> > -----Original Message-----
> > From: owner-nanfa-l-in-nanfa.org [owner-nanfa-l-in-nanfa.org]On Behalf Of
> > Bob Muller
> > Sent: Monday, February 14, 2005 8:21 PM
> > To: nanfa-l-in-nanfa.org
> > Subject: NANFA-L-- Michigan Chapter
> >
> >
> >
> >
> > Last week I gave a talk on native fishes to the Clinton Valley
> chapter of
> > Trout Unlimited. It was well received with lots of questions
> and interest in
> > the other fish in their trout streams. One question I have
> never gotten
> > before. In talking about the madtoms venom I was asked what
> for. I would
> > guess it helps them from being eaten any other ideas.
> >
> >
> >
> > Bob Muller
> >
> > Red Run (the ghost river of Royal Oak)
> >
> > a tributary of the Clinton River, Michigan
> >
> >
> >
> >
> >
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