Food in the Anthropocene: the EAT–Lancet Commission on healthy diets from sustainable food systems

Fast and frugal heuristics - simple rules for making decisions with realistic mental resources - are presented here. These heuristics can enable both living organisms and artificial systems to make smart choices, classifications, and predictions by employing bounded rationality. But when and how can such fast and frugal heuristics work? What heuristics are in the mind's adaptive toolbox, and what building blocks compose them? Can judgments based simply on a single reason be as accurate as those based on many reasons? Could less knowledge even lead to systematically better predictions than more knowledge? This book explores these questions by developing computational models of heuristics and testing them through experiments and analysis. It shows how fast and frugal heuristics can yield adaptive decisions in situations as varied as choosing a mate, dividing resources among offspring, predicting high school drop-out rates, and playing the stock market.

Simple Heuristics That Make Us Smart

Summary: Picante is a software package that provides a comprehensive set of tools for analyzing the phylogenetic and trait diversity of ecological communities. The package calculates phylogenetic diversity metrics, performs trait comparative analyses, manipulates phenotypic and phylogenetic data, and performs tests for phylogenetic signal in trait distributions, community structure and species interactions. Availability: Picante is a package for the R statistical language and environment written in R and C, released under a GPL v2 open-source license, and freely available on the web (http://picante .r-forge.r-project.org) and from CRAN (http://cran.r-project.org).

Picante: R tools for integrating phylogenies and ecology

Studies of local adaptation provide important insights into the power of natural selection relative to gene flow and other evolutionary forces. They are a paradigm for testing evolutionary hypotheses about traits favoured by particular environmental factors. This paper is an attempt to summarize the conceptual framework for local adaptation studies. We first review theoretical work relevant for local adaptation. Then we discuss reciprocal transplant and common garden experiments designed to detect local adaptation in the pattern of deme · habitat interaction for fitness. Finally, we review research questions and approaches to studying the processes of local adaptation ‐ divergent natural selection, dispersal and gene flow, and other processes affecting adaptive differentiation of local demes. We advocate multifaceted approaches to the study of local adaptation, and stress the need for experiments explicitly addressing hypotheses about the role of particular ecological and genetic factors that promote or hinder local adaptation. Experimental evolution of replicated populations in controlled spatially heterogeneous environments allow direct tests of such hypotheses, and thus would be a valuable way to complement research on natural populations.

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Conceptual issues in local adaptation

The main drivers of global environmental change (CO2 enrichment, nitrogen deposition, climate, biotic invasions and land use) cause extinctions and alter species distributions, and recent evidence shows that they exert pervasive impacts on various antagonistic and mutualistic interactions among species. In this review, we synthesize data from 688 published studies to show that these drivers often alter competitive interactions among plants and animals, exert multitrophic effects on the decomposer food web, increase intensity of pathogen infection, weaken mutualisms involving plants, and enhance herbivory while having variable effects on predation. A recurrent finding is that there is substantial variability among studies in both the magnitude and direction of effects of any given GEC driver on any given type of biotic interaction. Further, we show that higher order effects among multiple drivers acting simultaneously create challenges in predicting future responses to global environmental change, and that extrapolating these complex impacts across entire networks of species interactions yields unanticipated effects on ecosystems. Finally, we conclude that in order to reliably predict the effects of GEC on community and ecosystem processes, the greatest single challenge will be to determine how biotic and abiotic context alters the direction and magnitude of GEC effects on biotic interactions.

/pdf/global-change-and-species-interactions-in-terrestrial-26w7hzgeca.pdf

Global change and species interactions in terrestrial ecosystems.

Food security is high on the global policy agenda. Demand for food is increasing as populations grow and gain wealth to purchase more varied and resource-intensive diets. There is increased competition for land, water, energy, and other inputs into food production. Climate change poses challenges to agriculture, particularly in developing countries ( 1 ), and many current farming practices damage the environment and are a major source of greenhouse gases (GHG). In an increasingly globalized world, food insecurity in one region can have widespread political and economic ramifications ( 2 ).

/pdf/sustainable-intensification-in-agriculture-premises-and-4kl5b3g7y5.pdf

Sustainable Intensification in Agriculture: Premises and Policies

The extent to which an organism is selected to invest in defences against pathogens and parasites depends on the advantages that ensue should infection occur, but also on the costs of maintaining defences in the absence of infection. The presence of heritable variation in resistance suggests that costs exist, but we know very little about the nature or magnitude of these costs in natural populations of animals1. A powerful technique for identifying trade-offs between fitness components is the study of correlated responses to artificial selection2,3. We have selected Drosophila melanogaster for improved resistance against an endoparasitoid, Asobara tabida. Endoparasitoids are insects whose larvae develop internally within the body of other insects, eventually killing them, although their hosts can sometimes survive attack by mounting a cellular immune response4,5,6. We found that reduced larval competitive ability in unparasitized D. melanogaster is a correlated response to artificial selection for improved resistance against A. tabida. The strength of selection for competitive ability and parasitoid resistance is likely to vary temporally and spatially, which may explain the observed heritable variation in resistance.

Trade-off between parasitoid resistance and larval competitive ability in Drosophila melanogaster

Aphids are associated with several facultative bacterial endosymbionts that may influence their interactions with other organisms We show here that one of the three most common facultative symbionts of pea aphid (Acyrthosiphon pisum), the bacterium Regiella insecticola, has a major effect on host resistance to a fungal pathogen Experimental establishment of the bacterium in uninfected aphid clones led to higher survival after fungal attack The bacteria also increased the aphid's inclusive fitness, because the presence of the symbiont reduced the probability of fungal sporulation on aphid cadavers, hence lowering the rate of transmission of the disease to nearby related aphids

https://science.sciencemag.org/content/sci/310/5755/1781.full.pdf

Aphid Protected from Pathogen by Endosymbiont

THE young of birds and mammals often solicit food from their parents in ways that appear to be costly and to reduce their fitness1, 2. Thus birds in the nest beg vigorously for food, incurring energetic costs and possibly attracting predators3; the behaviour of young mammals requiring to suckle (bleating or crying, for example) similarly appears costly1, 2. If solicitation is a means by which the young communicate need to their parents, why has a less expensive form of communication not evolved4? An answer to this question is provided by the theory of parent–offspring conflict: natural selection acting on genes expressed in the young will lead to greater demands for parental resources than is optimal for the parent1, 5. The accurate communication of offspring need is evolutionarily unstable as offspring will be selected to demand extra resources. Models of parent–offspring conflict have shown that an evolutionarily stable equilibrium can exist at which an offspring solicits resources in a way that reduces its fitness, and a parent provides extra resources to prevent further expensive solicitation6–11. I present an alternative explanation for costly solicitation by showing that the level of offspring solicitation can be a true reflection of offspring need as long as solicitation is costly and the benefits of extra resources increase with need. My analysis suggests that the parent normally allocates resources using accurate information about the condition of the young. The requirement that the signalling system is costly is a direct consequence of the potential for parent–offspring conflict.

Signalling of need by offspring to their parents

Natural selection can act in different ways on genes expressed in parents and their young, giving rise to parent-offspring conflict. The way in which this genetic conflict manifests itself at the behavioural level is unclear, and there has been widespread dissatisfaction that the theory has provided few testable predictions. A recent shift in emphasis from models that define the possible extent of conflict to those that predict its resolution offers greater hope of a testable theory of parent-offspring conflict.

H. C. J. Godfray

Papers

Sustainable Intensification in Agriculture: Premises and Policies

Trade-off between parasitoid resistance and larval competitive ability in Drosophila melanogaster

Aphid Protected from Pathogen by Endosymbiont

Signalling of need by offspring to their parents

Evolutionary theory of parent-offspring conflict