Feedbacks across biological scales: Linking adaptive landscapes and species interaction networks

Matt Barbour
Jordi Bascompte
Kentaro Shimizu
Meredith Schuman

Aim: Mechanistic understanding of feedbacks between biological scales (gene, phenotype, population, and community scales).

Research: This work’s unique focus on feedbacks between genes and species-interaction networks will help integrate the URPP’s strengths in genomics and community ecology. This work complements the population-level focus of NeighborGen. Genetic variation within species often plays a key role in determining community- and ecosystem-level processes. Despite its ecological importance, we remain unable to predict how genetic evolution will alter ecological dynamics. Similarly, we do not know how genetic evolution unfolds in complex ecological communities. This is because we lack a mechanistic understanding of how allelic variation at specific genes influence the network of direct and indirect interactions between species in an ecological community (and vice versa). Our experiments explore the mechanistic feedbacks between genes and species-interaction networks, providing a novel integration of evolutionary genomics and community ecology. We expect that our work will pave the way toward a synthesis of these traditionally separate lines of research. A mechanistic understanding of the gene-to-ecosystem processes that structure species-interaction networks will enable better predictions of how genetic and species diversity will respond to global change.

How does the network structure of species interactions affect a population’s adaptive landscape and how does genetic change affect community dynamics? To answer these questions, we use a multi-trophic community comprising the plant Arabidopsis thaliana, three aphids (Myzus persicae, Brevicoryne brassicae, and Lipaphis erysimi), three parasitoid wasps (Diaeretiella rapae, Aphidius colemani, and Praon sp.), and a hyperparasitoid (Alloxysta sp.). This community is uniquely suited for examining the mechanistic feedbacks between the gene, phenotype, population, and community scales. We can orthogonally manipulate the presence/absence of functional alleles in plant genes that control phenotypes involved in species interactions in a common genetic background. By using a response surface design, we can quantify the adaptive landscape of specific genes in different community contexts (i.e., network structures) without confounding variation in other regions of the genome. Moreover, we can use the same response surface design to test for feedback of genetic change on community dynamics, by quantifying changes in the abundance of interacting species through time.