Glenn:
I found the elusive article in yet another of my piles of "good stuff."
The article is titled "A Diet-Induced Developmental Polymorphism in a
Caterpiller" and appears on page 643 of SCIENCE, Volume 243, 3 February,
1989. A short "popular" account also appears in Newsweek for Febuary 13,
1989.
The caterpiller is Nemoria arizonaria. Young who eat oak catkins soon take
on the general appearance of those fuzzy dangling flowers; young who eat
oak leaves wind up looking like the twigs the leaves hang from. The key
ingredient appears to be tannin, found in the leaves but not in the
catkins.
The experiments were interesting; Erick Greene, the researcher, fed some
young catkins with tannin added; "most," but not all, apparently, developed
looking like twigs.
The phenomenon is not as rare as I remembered; it even has a name --
"developmental polymorphism." The Science article talkes a little about
this, cting some other examples. Among the environmental factors identified
which cause organisms to develop differently are temperature, humidity,
photoperiod, and other. The article, 2.5 pages long, has more. What caught
my eye when I saw it, I think, are two color photographs of two morphs,
full sibs, raised on different diets. If you can't locate the article, I
can scan it (including the photos) and shoot it to you.
The organism is found primarily in Arizona and the surrounding states. The
morphs differ quite a bit; I have no idea, however, if they would normally
be put into different phyla by researchers unfamiliar with their origins.
The question raised is, of course, were there such morphs present in early
organisms not only known to us in the fossil record? If so, perhaps the
number of unique phyla we recognize today might be overstated?
Best
Burgy
This archive was generated by hypermail 2b29 : Tue Oct 24 2000 - 13:51:40 EDT