Energetic basis for bird ontogeny and egg-laying applied to the bobwhite quail

Birds build up their reproductive system and undergo major tissue remodeling for each reproductive season. Energetic specifics of this process are still not completely clear, despite the increasing interest. We focused on the bobwhite quail — one of the most intensely studied species due to commercial and conservation interest — to elucidate the energy fluxes associated with reproduction, including the fate of the extra assimilates ingested prior to and during reproduction. We used the standard Dynamic Energy Budget model, which is a mechanistic process-based model capable of fully specifying and predicting the life cycle of the bobwhite quail: its growth, maturation and reproduction. We expanded the standard model with an explicit egg-laying module and formulated and tested two hypotheses for energy allocation of extra assimilates associated with reproduction: Hypothesis 1, that the energy and nutrients are used directly for egg production ; and Hypothesis 2, that the energy is mostly spent fueling the increased metabolic costs incurred by building up and maintaining the reproductive system and, subsequently, by egg-laying itself. Our results suggest that Hypothesis 2 is the more likely energy pathway. Model predictions capture well the whole ontogeny of a generalized northern bobwhite quail and are able to reproduce most of the data variability via variability in (i) egg size, (ii) egg-laying rate and (iii) inter-individual physiological variability modeled via the zoom factor, i.e. assimilation potential. Reliable models with a capacity to predict physiological responses of individuals are relevant not only for experimental setups studying effects of various natural and anthropogenic pressures on the quail as a bird model organism, but also for wild quail management and conservation. The model is, with minor modifications, applicable to other species of interest, making it a most valuable tool in the emerging field of conservation physiology

Mechanistic effect modeling of earthworms in the context of pesticide risk assessment: Synthesis of the FORESEE Workshop.

Earthworms are important ecosystem engineers, and assessment of the risk of plant protection products towards them is part of the European environmental risk assessment (ERA). In the current ERA scheme, exposure and effects are represented simplistically and are not well integrated, resulting in uncertainty when applying the results to ecosystems. Modeling offers a powerful tool to integrate the effects observed in lower tier laboratory studies with the environmental conditions under which exposure is expected in the field. This paper provides a summary of the FORESEE Workshop ((In)Field Organism Risk modEling by coupling Soil Exposure and Effect) held January 28‐30, 2020 in Düsseldorf, Germany. This workshop focussed on toxicokinetic‐toxicodynamic (TKTD) and population modeling of earthworms in the context of environmental risk assessment. The goal was to bring together scientists from different stakeholder groups to discuss the current state of soil invertebrate modeling, explore how earthworm modeling could be applied to risk assessments, and in particular how the different model outputs can be used in the tiered ERA approach. In support of these goals, the workshop aimed at addressing the requirements and concerns of the different stakeholder groups to support further model development. The modeling approach included four submodules to cover the most relevant processes for earthworm risk assessment: Environment, Behavior (feeding, vertical movement), TKTD, and Population. Four workgroups examined different aspects of the model with relevance for: Risk assessment, earthworm ecology, uptake routes, and cross‐species extrapolation and model testing. Here, we present the perspectives of each workgroup and highlight how the collaborative effort of participants from multidisciplinary backgrounds helped to establish common ground. In addition, we provide a list of recommendations for how earthworm TKTD modeling could address some of the uncertainties in current risk assessments for plant protection products

Bean data Figure 4

Time-resolved data of leaf are index, above ground vegetative mass and pod mas

Trout data Figure 3b

Final body and egg mas

Trout data Figure 3a

time resolved measurements of body weight and egg mass of 12 individual

Trout data Figure 2

Includes time-resolved measurements of wet weight of body, ovaries and liver, egg diameter and plasma content of vitellogenin and estradiol of 58 individuals

Regulation of reproductive processes with dynamic energy budgets

Linking organismal‐level processes to underlying suborganismal mechanisms at the molecular, cellular and organ level constitutes a major challenge for predictive ecological risk assessments. This challenge can be addressed with the simple bio-energetic models in the family of dynamic energy budget (DEB), which consist of a small number of state equations quantifying universal processes, such as feed-ing, maintenance, development, reproduction and growth.2. Motivated by the need for process‐based models to evaluate the impact of endo-crine disruptors on ecologically relevant endpoints, this paper develops and evalu-ates two general modelling modules describing demand‐driven feedbackmechanisms within the DEB modelling framework exerted by gonads on the allo-cation of resources to production of reproductive matter.3. These modules describe iteroparous, semelparous and batch‐mode reproductive strategies. The modules have a generic form with both positive and negative feed-back components; species‐ and sex‐specific attributes of endocrine regulation can be added without changing the core of the modules.4. We demonstrate that these modules successfully describe time‐resolved meas-urements of wet weight of body, ovaries and liver, egg diameter and plasma con-tent of vitellogenin and oestradiol in rainbow trout (Oncorynchus mykiss) by fitting these models to published and new data, which require the estimation of less than two parameters per data type.5. We illustrate the general applicability of the concept of demand‐driven allocationof resources to reproduction by evaluating one of the modules with data on growth and seed production of an annual plant, the common bean (Phaseolisvulgaris)

The Effect of Dietary Exposure to Coal Ash Contaminants within Food Ration on Growth and Reproduction inDaphnia magna

Coal ash contains numerous contaminants and is the focus of regulatory actions and risk assessments due to environmental spills. We exposedDaphnia magnato a gradient of coal ash contamination under high and low food rations to assess the sublethal effects of dietary exposures. Whereas exposure to contaminants resulted in significant reductions in growth and reproduction in daphnids, low, environmentally relevant food rations had a much greater effect on these endpoints.Environ Toxicol Chem2020;00:1-10. (c) 2020 SETA