Re: NANFA-- AC article on Fundulus lima

Christopher Scharpf (ichthos_at_charm.net)
Thu, 31 May 2001 09:35:41 -0400

Arndt observed:

>i found the article on the F. lima splashing its eggs in the air to be
>interesting. however, it seems to me that there is a very simple
>explanation for the behavior. since as stated in the article the lima will
>eat the eggs. then it seems they scatter the eggs randomly through the air
>so that they themselves cannot find them so easily to eat every egg. thus
>some eggs are not eatten. very simple. all the evidence in the article
>points this out. the F lima fish in the middle of a pond ( or aquarium )
>will spawn and scatter the eggs. there is nothing around above the water.
>but there are the hungry parents below the water ready to eat every egg they
>can spot.

John Brill replies:

Arndt:

Hey. Thanks for commenting. I very explicitly pointed out the evolutionary
rationale that you suggest in the first full paragraph on page 20:

A further possibility is that the spawning behavior of F. lima is not
designed to deposit eggs on terrestrial surfaces. Commenting on a similar
observation by Mayer (1932) in the European species Valencia hispanica,
Breder and Rosen (1966) claim that such aquarium behavior may simply mean
that, in nature, the eggs are widely scattered and not necessarily directed
toward extra-aquatic objects

Even so, it's not so simple. There are more than thirty species of Fundulus,
all of which--including the very simlar F. parvipinnis, from which F. lima is
relatively recently derived--consistently deposit eggs against a substrate,
and, moreover, that are just as inclined to eat their own eggs. And this also
holds for almost all of the several hundred species of killifishes. Viewed in
context, the spawning behavior of F. lima is as idiosyncratic and
counterintuitive as I suggest it to be, the above paragrpah notwithstanding.
Were splashing an effective mode of egg dispersal--that is, effective enough
to preclude parental predation--you might expect to see it appear more than
once among the cyprinodontiforms. While it could have evolved in F. lima
alone, I don't think it's as unambiguous as you make it out to be.

Best regards...
Brill

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