Ecological Separation in an Ongoing Speciation Event

Abstract

There are many factors that contribute to speciation events. Pollination is often seen as the biggest driver of speciation particularly when pollinators discriminate against certain traits. This discrimination of pollinators is driven by a variety of plant morphological traits, possibly leading specific pollinators to have a strong plant preference. However, phenological characteristics can serve an important role in separating species. For instance, if two plants differ in flowering time then there will be reproductive isolation between them, which then leads to potential speciation. These biotic and phenotypic influences can act together to rapidly diversify plant lineages. Studying these differences between pollinator preference and phenological differences can be important for predicting gene flow and how speciation events may start to occur. We tested for differences in phenological patterns by completing a series of experiments using two subspecies of rabbitbrush; germination trials, multiple observational field trials, and chemical analysis. This study will provide an understanding of the ongoing diversification events of rabbitbrush. Thereby, contributing to a more general and deeper understanding of how ecological roles, between pollinator and plant, contribute to evolution. It also may answer questions about what makes a species a species or subspecies. The specific focus of this paper will be on germination phenological characters.