Seed choice by rodents: learning or inheritance?

Learning plays a central role in animal life, and it has received special attention in the context of foraging. In this study, we have tested whether learning operates in seed choices by rodents using the Algerian mouse (Mus spretus) and Holm oak (Quercus ilex) acorns as a model. At the laboratory, those rodents captured in the field during the acorn fall period (experienced individuals) rejected weevil-infested acorns, presumably because of their lower energetic value. By contrast, rodents born in captivity and reared without any contact with acorns (naïves) predated weevil-infested acorns at similar rates than sound ones. After exposing naïves to infested and sound acorns during 15 days, they rejected infested acorns as the experienced individuals. In the field, predation on weevil-infested acorns was lower than on sound ones. Predation rates on infested acorns were lowest at the end of the acorn fall season, whereas predation rates of sound acorns increased along the same period. This might be explained by the improved ability to reject infested acorns because of the accumulated experience acquired by the initially naïve rodents along the acorn fall season. We show that learning shapes strongly seed choices by rodents, and it may be advantageous over inherited behaviors in variable unpredictable situations, such as acorn infestation rates that vary strongly between years and trees. We consider that the role of learning has to be taken into account in future studies on seed predation by rodents.     

Animal Rearing as a Contract?

Can animals, and especially cattle, be the subject ofmoral concern? Should we care about their well-being?Two competing ethical theories have addressed suchissues so far. A utilitarian theory which, inBentham's wake, extends moral consideration to everysentient being, and a theory of the rights orinterests of animals which follows Feinberg'sconceptions. This includes various positions rangingfrom the most radical (about animal liberation) tomore moderate ones (concerned with the well-being ofanimals). Notwithstanding their diversity, theseconceptions share some common flaws. First, as anextension of primarily anthropocentric theories (aboututility or rights) they still participate in the flawsof the original setting. Second, extending them tonon-human beings raises the problem of the borderwhich is to be drawn between what can be included inthe purview of moral consideration and what is leftoutside. Third, such theories are not able to distinguishbetween an ethics of wildlife and an ethics ofdomestic life, which too often leads to preposterousstatements. We would like to argue (i) that we should distinguishbetween environmental ethics (concerned withpopulations, species, biotic communities) and animalethics (where animals are taken into consideration individually);(ii) that individualist animal ethics are not relevantfor animal rearing; (iii) that animal rearing is a hierarchicalrelationship which rules are to be found in the fiction of a domesticcontract. Hence, we would like to construct a new conception ofthe ethics of the relation between men and the cattlethey breed based on the idea of a domestic contract.Our main assumption is Mary Midgleys's anthropologicalassumption, according to which human communities,since the Neolithic age, have always included variousanimals, so that relations of sociability have alwaysexisted between human beings and animals within thedomestic community (a mixed community). In order tospecify the hierarchical and non-egalitarian, butinclusive reciprocal obligations and relations insidesuch a community, we will elaborate on the notion ofa ``domestic contract'', an implicitly assumedidea traced back to Lucretius and whichwe will follow up to the physiocrats and Adam Smith.We will show that such an idea relies upon theassumption of communication between cattle farmer andanimals, of shared experience and exchanges betweenthe two parties. We will then show how modern factory,or battery animal farming, can be seen as unilaterallybreaking this domestic contract, forsaking ourduties towards domestic animals.     

Metabolic adaptation of fungal strains in response to contamination by polychlorinated biphenyls

Environmental Science and Pollution Research - Polychlorinated biphenyls (PCBs) represent a large group of recalcitrant environmental pollutants. Up to now, many studies have focused on...     

Chronic dietary exposure to pyrolytic and petrogenic mixtures of PAHs causes physiological disruption in zebrafish—part II: behavior

In the last 10 years, behavior assessment has been developed as an indicator of neurotoxicity and an integrated indicator of physiological disruption. Polycyclic aromatic hydrocarbon (PAH) release into the environment has increased in recent decades resulting in high concentrations of these compounds in the sediment of contaminated areas. We evaluated the behavioral consequences of long-term chronic exposure to PAHs, by exposing zebrafish to diets spiked with three PAH fractions at environmentally relevant concentrations. Fish were exposed to these chemicals from their first meal (5 days postfertilization) until they became reproducing adults (at 6 months old). The fractions used were representative of PAHs of pyrolytic (PY) origin and of two oils differing in composition (a heavy fuel oil (HO) and a light crude oil (LO)). Several tests were carried out to evaluate circadian spontaneous swimming activity, responses to a challenge (photomotor response), exploratory tendencies, and anxiety levels. We found that dietary PAH exposure was associated with greater mobility, lower levels of exploratory activity, and higher levels of anxiety, particularly in fish exposed to the HO fraction and, to a lesser extent, the LO fraction. Finally, our results indicate that PAH mixtures of different compositions, representative of situations encountered in the wild, can induce behavioral disruptions resulting in poorer fish performance.     

Developmental toxicity of PAH mixtures in fish early life stages. Part I: adverse effects in rainbow trout

A new gravel-contact assay using rainbow trout, Oncorhynchus mykiss, embryos was developed to assess the toxicity of polycyclic aromatic hydrocarbons (PAHs) and other hydrophobic compounds. Environmentally realistic exposure conditions were mimicked with a direct exposure of eyed rainbow trout embryos incubated onto chemical-spiked gravels until hatching at 10 °C. Several endpoints were recorded including survival, hatching delay, hatching success, biometry, developmental abnormalities, and DNA damage (comet and micronucleus assays). This bioassay was firstly tested with two model PAHs, fluoranthene and benzo[a]pyrene. Then, the method was applied to compare the toxicity of three PAH complex mixtures characterized by different PAH compositions: a pyrolytic extract from a PAH-contaminated sediment (Seine estuary, France) and two petrogenic extracts from Arabian Light and Erika oils, at two environmental concentrations, 3 and 10 μg g^?1 sum of PAHs. The degree and spectrum of toxicity were different according to the extract considered. Acute effects including embryo mortality and decreased hatching success were observed only for Erika oil extract. Arabian Light and pyrolytic extracts induced mainly sublethal effects including reduced larvae size and hemorrhages. Arabian Light and Erika extracts both induced repairable DNA damage as revealed by the comet assay versus the micronucleus assay. The concentration and proportion of methylphenanthrenes and methylanthracenes appeared to drive the toxicity of the three PAH fractions tested, featuring a toxic gradient as follows: pyrolytic?Arabian Light?Erika. The minimal concentration causing developmental defects was as low as 0.7 μg g^?1 sum of PAHs, indicating the high sensitivity of the assay and validating its use for toxicity assessment of particle-bound pollutants.     

Ant cuticular response to phthalate pollution

Phthalates are common atmospheric contaminants used in the plastic industry. Ants have been shown to constitute good bioindicators of phthalate pollution. Hence, phthalates remain trapped on ant cuticles which are mostly coated with long-chain hydrocarbons. In this study, we artificially contaminated Lasius niger ants with four phthalates: dibutyl phthalate (DBP), diisobutyl phthalate (DiBP), di(2-ethylhexyl) phthalate (DEHP), and benzyl butyl phthalate (BBP). The first three have previously been found on ants in nature in Touraine (France), while the fourth has not. The four phthalates disappeared rapidly (less than 5 days) from the cuticles of live ants. In contrast, on the cuticles of dead ants, DEHP quantities remained unchanged over time. These results indicate that phthalates are actively absorbed by the cuticles of live ants. Cuticular absorption of phthalates is nonspecific because eicosane, a nonnatural hydrocarbon on L. niger cuticle, was similarly absorbed. Ants are important ecological engineers and may serve as bioindicators of ecosystem health. We also suggest that ants and more generally terrestrial arthropods may contribute to the removal of phthalates from the local environment.     

Biological responses of midge (Chironomus riparius) and lamprey (Lampetra fluviatilis) larvae in ecotoxicity assessment of PCDD/F-, PCB- and Hg-contaminated river sediments

Environmental Science and Pollution Research - We evaluated the utility of chironomid and lamprey larval responses in ecotoxicity assessment of polychlorinated dibenzo-p-dioxins, dibenzofurans...     

Climate change impacts on European agriculture revisited: adding the economic dimension of grasslands

Forage and more widely grassland systems are difficult to analyze in economic terms because a large proportion of what is produced is not marketed. Economic misestimation of these farm products may dramatically alter projected climate change impacts. This study estimates the economic value of grass and assesses the impact of climatic variations on grassland–livestock systems by taking various environmental and climatic factors into account. Accordingly, grass yield responses to nitrogen inputs (N-yield functions) have been simulated using the grassland biogeochemical PaSim model and then fed into the economic farm-type supply AROPAj model. We developed a computational method to estimate shadow prices of grass production, allowing us to better estimate the effects of climatic variability on grassland and crop systems. This approach has been used on a European scale under two Intergovernmental Panel on Climate Change climate scenarios (AR4 A2 and B1). Results show a significant change in land use over time. Accordingly, due to decreases in feed expenses, farmers may increase livestock, thereby increasing overall greenhouse gas emissions for all scenarios considered. As part of autonomous adaptation by farming systems, N-yield functions extending to pastures and fodders allow us to improve the model and to refine results when marketed and non-marketed crops are considered in a balanced way.     

In Flanders Fields: De/politicization and Democratic Debate on a GM Potato Field Trial Controversy in News Media

In May 2011, a highly mediatized direct action in the form of a “field liberation” took place in Flanders, Belgium, against a field trial of genetically modified potatoes. This direct action and its aftermath revealed the conflictual and antagonistic nature of the genetically modified organisms debate in Flanders. Consequently, it serves as a particularly suitable case to investigate the post-political thesis with regard to environmental discourse and politics. The aim of this paper is to investigate in what ways news media in their reporting contribute to processes of depoliticization and, resultantly, impede a democratic debate on the issues at stake. This paper attempts to provide an answer to this question based on a critical discourse analysis of the reporting by Flanders’ two generalist, elite newspapers, De Standaard and De Morgen and the alternative online news site DeWereldMorgen. The findings reveal the existence of three ideological cultures, which are characterized by different degrees of de/politicization. We conclude by discussing how this study adds to our understanding of the relation between the depoliticization of environmental discourse, democratic debate and twenty-first-century news media.