Phenotypic plasticity is the primitive character state for most if not all traits. Insofar as
developmental and physiological processes obey the laws of chemistry and physics, they will be …

Explaining the origins of novel traits is central to evolutionary biology. Longstanding theory
suggests that developmental plasticity, the ability of an individual to modify its development in …

▪ Abstract We discuss a framework for studying the evolution of morphology in insects, based
on the concepts of “phenotypic plasticity” and “reaction norms.” We illustrate this approach …

… A numbering system is therefore used to identify the five major clusters of neurosecretory
cells in Manduca (Nijhout, 1975a). During metamorphosis of Manduca, a new group of neu- …

… coenia had been tentatively identified as a phaeomelanin, based on its insolubility in all but
the harshest solvents (Nijhout, 1980a). We (PB Koch and Nijhout, unpub. data) have recently …

… These spots appear when larvae are infused with a subthreshold dose of ecdysone in the
presence of JH (Nijhout, unpublished). They consist of a melanization of the larval cuticle and …

Polyphenisms are adaptations in which a genome is associated with discrete alternative
phenotypes in different environments. Little is known about the mechanism by which …

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 …

Control mechanisms that regulate body size and tissue size have been sought at both the
cellular and organismal level. Cell-level studies have revealed much about the control of cell …

… the final-instar larva reaches a certain critical weight (Nijhout and Williams, 1974a, b). In this
case … JH from the circulatory system and to allow its covert effects to decay (Nijhout, 1975b). …