Definition of "polyphenic"

Both types of threshold mechanism have been shown to couple horn growth with nutrition in scarab beetles and are considered facultative (polyphenic) regulatory processes, and preliminary evidence suggested that they might sometimes both be present in the same species.

2009 February 6, J. Mark Rowland, Douglas J. Emlen, “Two Thresholds, Three Male Forms Result in Facultative Male Trimorphism in Beetles”, in Science‎, volume 323, number 5915, pages 773–776