The evolution of chemodiversity - From verbal to quantitative models

Abstract

Plants harbour a great chemodiversity, i.e., diversity of specialized metabolites (SMs), at different scales. For instance, individuals can produce a large number of SMs and populations can differ in their metabolite composition. Given the ecological and economic importance of plant chemodiversity, it is important to understand how it arises and is maintained over evolutionary time. For other dimensions of biodiversity, i.e., species diversity and genetic diversity, quantitative models play an important role in addressing such questions. Here we provide a synthesis of existing hypotheses and quantitative models, i.e. mathematical models and computer simulations, for the evolution of plant chemodiversity. We describe each model’s ingredients, i.e., the biological processes that shape chemodiversity, the scales it considers, and whether it has been formalized as a quantitative model. Although we identify several quantitative models, not all are dynamic and many influential models have remained verbal. To fill these gaps, we identify quantitative models used for genetic variation that may be adapted for chemodiversity. We end by outlining our vision for the future of chemodiversity modeling, presenting a flexible framework for the creation of individual-based models that address different scales of chemodiversity and combine different ingredients that bring this chemodiversity about.

How does plant chemodiversity evolve? Testing five hypotheses in one population genetic model

“…Potential answers to such questions are offered by a number of hypotheses and verbal models (for reviews, see Moore et al . 2014; Thon et al . 2024; Wetzel and Whitehead 2020).…”

“…2014). Such models exist for genetic variation and for species diversity, but so far there is a relatively small number of quantitative models for chemodiversity (reviewed in Thon et al . 2024).…”

“…To test whether these verbal models "work", i.e., whether the claimed predictions actually follow from the assumptions, and to find out what exact patterns of chemodiversity they predict, quantitative models such as simple mathematical models and detailed computer simulations are needed (Servedio et al 2014). Such models exist for genetic variation and for species diversity, but so far there is a relatively small number of quantitative models for chemodiversity (reviewed in Thon et al 2024). The existing quantitative models include optimality models that predict investment in defenses based on resource constraints (e.g., Coley et al 1985;Orrock et al 2015;Yamamura and Tsuji 1995), evolutionary game theory and frequency-dependent selection models that explain coexistence between defended and undefended plants based on direct and indirect interactions between plants in neighborhoods (e.g., Augner et al 1991;Lankau 2009;Sato et al 2017), as well as simulation models for plant-herbivore coevolution (e.g., Speed et al 2015).…”

“…Potential answers to such questions are offered by a number of hypotheses and verbal models (for reviews, see Moore et al 2014;Thon et al 2024;Wetzel and Whitehead 2020). To test whether these verbal models "work", i.e., whether the claimed predictions actually follow from the assumptions, and to find out what exact patterns of chemodiversity they predict, quantitative models such as simple mathematical models and detailed computer simulations are needed (Servedio et al 2014).…”