Linking genes to communities and ecosystems: Daphnia as an ecogenomic model

Abstract

How do genetic variation and evolutionary change in critical species affect the composition and functioning of populations, communities and ecosystems? Illuminating the links in the causal chain from genes up to ecosystems is a particularly exciting prospect now that the feedbacks between ecological and evolutionary changes are known to be bidirectional. Yet to fully explore phenomena that span multiple levels of the biological hierarchy requires model organisms and systems that feature a comprehensive triad of strong ecological interactions in nature, experimental tractability in diverse contexts and accessibility to modern genomic tools. The water flea Daphnia satisfies these criteria, and genomic approaches capitalizing on the pivotal role Daphnia plays in the functioning of pelagic freshwater food webs will enable investigations of eco-evolutionary dynamics in unprecedented detail. Because its ecology is profoundly influenced by both genetic polymorphism and phenotypic plasticity, Daphnia represents a model system with tremendous potential for developing a mechanistic understanding of the relationship between traits at the genetic, organismal and population levels, and consequences for community and ecosystem dynamics. Here, we highlight the combination of traits and ecological interactions that make Daphnia a definitive model system, focusing on the additional power and capabilities enabled by recent molecular and genomic advances.

Thermal evolution offsets the elevated toxicity of a contaminant under warming: A resurrection study in Daphnia magna

“…Daphnia are important organisms to address evolutionary responses to stressors as they are keystone species in aquatic food webs (Miner, De Meester, Pfrender, Lampert, & Hairston, 2012) and model species in ecotoxicology (OECD 2004). Moreover, as Daphnia produce resting eggs that are viable for many years, one can reconstruct evolution across decades (Orsini et al., 2013).…”

Monogonont rotifers as model systems for the study of micro-evolutionary adaptation and its eco-evolutionary implications

“…The choice of a suitable model organism is particularly crucial. Cladocerans and monogonont rotifers both share a set of traits that make them ideal model organisms for the study of microevolution in metazoans (Fussmann, 2011;Miner et al, 2012). They are relatively small and easy to handle and culture.…”

“…The possibilities offered by this unique combination of traits have been intensively exploited in research on Daphnia (Miner et al, 2012). However, this is much less so in the case of monogonont rotifers.…”

“…Rapid adaptation is also a potentially important determinant of gene flow among populations (monopolization hypothesis;De Meester et al, 2002), and is a key process in the theoretical framework of evolving metacommunities (Urban et al, 2012). Furthermore, the consequences of evolutionary changes in the phenotype of organisms may go as far as impacting the functioning of entire ecosystems (Matthews et al, 2011(Matthews et al, , 2014Miner et al, 2012).…”

Food availability affects the strength of mutualistic host–microbiota interactions in Daphnia magna

“…Here we address this issue using the water flea Daphnia magna and its symbiotic microbial community as a model system. D. magna is a keystone species in many freshwater habitats and has been widely used as an experimental system to study ecological and evolutionary interactions (for example, Decaestecker et al, 2007;Miner et al, 2012). Daphnia is known to harbor high numbers of bacteria on the surface of its body and in its gut (Grossart et al, 2010;Eckert & Pernthaler, 2014), and Qi et al (2009) showed that several bacterial taxa are consistently found in affiliation with Daphnia, even in geographically separated populations, indicating a highly specific association between Daphnia and its microbiota.…”