The Principle of Asymmetric Selection Inversion (ASI): A Conditional Framework for Selection Direction, Magnitude, and Regime Change

The Principle of Asymmetric Selection Inversion (ASI) is proposed as a conditional framework for investigating when asymmetries in reproductive investment, mating opportunity, trait costs, ecological constraints, and preference structure are associated with changes in selection. The framework distinguishes three outcomes that are often conflated: a change in selection magnitude, a change in the structure of a mating or selection regime, and a genuine sign inversion in the effect of a defined trait on a specified fitness-related outcome. Its motivating comparison, termed the Pavo-Homo Selection Paradox, concerns the contrast between male ornamentation and female mate choice in peafowl (Pavo cristatus) and the more context-dependent, often mutual, patterns of mate choice in humans (Homo sapiens). The comparison is treated as a hypothesis-generating case, not as evidence that selection universally points in opposite directions in the two species. A causal architecture is specified, candidate variables are organized, and a formal inversion criterion is given using a within-system fitness contrast or selection gradient. The manuscript also outlines a twelve-layer research architecture, twelve domain categories grouped into eight substantive and four methodological domains, a fourteen-step research workflow, four research phases, and three validation gates. No empirical inversion, universal threshold, or novel evolutionary law is claimed here. ASI will warrant a distinct theoretical contribution only if comparative analysis identifies explanatory or predictive value beyond established sexual-selection, parental-investment, life-history, ecological, genetic, and game-theoretic models. The present manuscript therefore provides a falsifiable research program and a disciplined basis for subsequent empirical and computational work. Keywords: sexual selection; mate choice; parental investment; selection gradient; reproductive success; life-history trade-offs; evolutionary ecology; model validation; falsifiability