Proximate Mechanisms and Ultimate Consequences of Speciation

Speciation is the process by which one species splits into two, leading to increases in biological diversity, both in terms of species richness and phenotypic diversity. The process of speciation entails a combination of phenotypic, genetic, ecological, and reproductive divergence. Often speciation research focuses on the emergent outcome of this divergence, such as reproductive isolation. But, the genetic divergence has detailed mechanistic underpinnings that must be understood if we are to build a comprehensive view of speciation processes. For example, hybrid inviability may be understood more fully through the lens of gene regulatory networks, or developmental biology. Premating reproductive isolation in animals often requires an understanding of the neurobiology and behavioral mechanisms of mate choice, while pollinator-mediated isolation between plants requires an understanding of pollinator ecology and sensory biology and behavior. Ecological speciation can trace its roots to detailed mechanistic understanding of prey capture and foraging decisions (for competition driven speciation), predator-prey interactions, or immunology for parasite-driven speciation. Speciation research therefore is enriched when it draws on detailed analysis of proximate mechanisms (e.g., genetic, developmental, physiological, ecological) that produce emergent properties like reproductive isolation. For the 2025 GRC on Speciation, we seek to bring together biologists studying a range of mechanistic processes that are pertinent to our understanding of speciation, to interact with other biologists who may make speciation and macroevolution their primary focus. By bridging the study of proximate mechanisms of divergence and ultimate outcomes for biodiversity, we hope to foster new collaborations, new insights, and to broaden the speciation research community.