Symposium > Keynote speakers

Pr. Chris Barnes

Keynote title: "Applying and Adapting DEB to Humans at Work"

DEB is a powerful theory for explaining metabolism across many (maybe all?) species. However, humans may have more agency in how energy is allocated than is currently appreciated by DEB. In a new paper, my colleagues and I developed a theory of human sustainability in the context of work, which we refer to as Restricted Employee Sustainability Theory (REST). REST was developed from the conceptual foundations of DEB. In this presentation, I will discuss how DEB informed REST, how REST challenges a few assumptions of DEB, and ultimately how this might inform our thinking about DEB. Some of the aspects of REST are likely specific to humans, but others may be useful to DEB more broadly, especially for species which experience social forces. I plan to close with a discussion of how DEB may be undersocialized and could potentially benefit from a more socialized perspective.

Pr. Tânia Sousa

Keynote title: "Metabolism in organisms and societies: differences and commonalities."

Metabolism as a concept was first developed in the context of Biology. It is applicable to all autopoietic (Varela & Maturama, 1992) entities: entities that can reproduce and maintain themselves. Currently, the concept of metabolism for a quantitative aggregate understanding of systems is applied to organisms using Dynamic Energy Budget (DEB) Theory (Kooijman, 2000) and to social systems such as cities, regions or countries, using other approaches such as Societal Exergy Accounting (Sousa et al., 2017), Economy-wide Material Flow Accounting (Fisher-Kowalski et al., 2011) and Multi-Scale Integrated Analysis of Societal and Ecosystem Metabolism (Giampietro et al., 2011). DEB theory provides a qualitative and quantitative description of how organisms take mass and energy flows from the environment and transform them in order to maintain themselves out of equilibrium, grow in size and increase in complexity in order to produce offspring that ensure their long-term survival. Sociometabolic approaches are not as successful as DEB theory in providing insights and predictions for social metabolism because they are accounting approaches that ensure mass and energy conservation but do not provide a description of the internal structure of the autopoietic system and of the metabolic processes and the allocation of flows to those processes. In this talk, I will make a presentation of the current approaches that describe the metabolism for countries and their main results. I will discuss the differences and commonalities between metabolism in organisms and societies and discuss the insights that we can take from DEB theory to further develop current sociometabolic approaches. Additionally, I will discuss insights for DEB theory that we can take from the role of information in social systems.

Dr. David Spurgeon

Keynote title: Ecotoxicology and TK-TD models: What lies beneath.

The outputs from TKTD models provide parameter values that relate the toxic effects of a given chemical or mixture, as they develop through time, to underlying physiological processes. Such outputs can help in the development of mechanistic hypotheses on the cause of specific toxicity patterns that can be tested experimentally. Readily available genomic and transcriptomic data contain a wealth of comparative molecular information that relates to the biochemistry that underpins the toxicokinetics and toxicodynamics of chemicals, e.g. differences in toxicant target receptors, xenometabolic capacity and damage mitigation pathways. Such data can play a valued role in efforts to link the molecular basis of chemical interactions with observed apical effects. With the spectacular rise in the availability of genomic data, it is now more possible that ever to catalogue TK and TD relevant traits, investigate how they differ between species and assess how those differences explain observed patterns of effects, such as difference in the sensitivity of species and the presence of interactions occurring in mixtures. This presentation will discuss how genomic information can be used to identify the mechanistic basis of toxicokinetic and toxicodynamic traits. We identify how these insights would augment current approaches used in basic and applied ecotoxicology research and review the power of existing omic predictive tools. With the aid of case study examples, we detail a ‘road map’ to can support progress towards integrating insights possible from mechanistic toxicogenomics with those arising from TKTD modelling.

Dr. David Civitello

Keynote title: Hungry hungry schistos: A multiscale DEB perspective on infectious disease outbreaks and control

Outbreaks of infectious disease affect host populations, ecological communities, the structure and function of natural and managed ecosystems, and global public health. Anticipating and controlling outbreaks requires a strong understanding of the individual-level traits of hosts and parasites. However, classic management strategies and models often assume that the traits of hosts and parasites are fixed, which implies that reductions in the densities of infected hosts or vectors should consistently reduce parasite transmission. Using a case study of human schistosomes and their intermediate host snails, I will illustrate how important individual-level traits are driven by underlying bioenergetics processes and environmental conditions (resource availability, variability, and competition). These dynamic trait changes yield three important consequences: (1) they sever the relationship between infected host density and transmission potential, (2) they facilitate brief periods of extreme human exposure risk during phases of snail population growth, and (3) they highlight conditions under which snail reduction can backfire, elevating human risk of exposure to schistosomes. Ultimately, a Dynamic Energy Budgeting perspective on host-parasite interactions could greatly improve prediction and control of infectious disease in a variety of systems.