[Nijhout, Emlen, PNAS, Mar '98]

Abstract:

"Changes in form during ontogeny and evolution depend in large
measure on changes in the relative growth of the various parts of the
body. The current consensus in developmental biology is that the
final size of appendages and internal organs is regulated
autonomously, within the structure itself. Size regulation of body
parts typically requires no external control and is thought to be
relatively insensitive to signals from the developmental environment.
We show in two very different systems, butterfly wings and beetle
horns, that experimentally induced changes in the allocation of
developmental resources to one trait produces compensatory changes in
the relative sizes of other traits. These findings illustrate that
interaction among body parts in development is part of the mechanism
of size regulation of those parts. Furthermore, in the case of beetle
horns, we show that the tradeoff in size is manifest as a significant
negative genetic correlation among the involved body parts and,
therefore, constitutes a developmental source of genetic constraint
on the evolution of body form."

Full text at:
http://www.pnas.org/cgi/content/full/95/7/3685

Jorolat