252 research outputs found

    How Institutions Shape Morality

    Get PDF
    We present the results of a randomized control trial on the effect of the introduction of formalized property rights on individuals' moral judgments and, in particular, on utilitarian morality. We show that institutions shape morality: being exposed to private property institutions makes individuals more utilitarian when confronted with moral dilemmas. Our results shed light on a possible institutional determinant of the variation of moral judgments across the globe and its geographical patterns, and have implications for the consequences of major institutional reforms-both intended, such as land-titling programs, and unintended, such as those following from recent historical events-on moral attitudes. We discuss two possible channels stemming from the inherent features of property rights: the loosening of social ties and the commodification of rights (JEL codes: K11; O13; Z10; Z13)

    Least Cost Avoidance: The Tragedy of Common Safety

    Get PDF
    This paper shows that the least cost avoider approach in tort is not necessarily the optimal way to attain least cost avoidance when accidents can be avoided by either of two parties. When parties do not observe each other\u27s costs of care at the time of the accident and are unable to determine which party is the least cost avoider, they fail to anticipate the outcome of the adjudication. Under these circumstances, accident avoidance becomes a commons problem because care by each individual party reduces the prospect of liability for both parties. As a result parties suboptimally invest in care. We show that regulation removes this problem and is superior to tort liability both when parties act simultaneously and when they act sequentially. We further examine how different liability rules perform in this respect

    Jasmonic acid-induced volatiles of Brassica oleracea attract parasitoids: effects of time and dose, and comparison with induction by herbivores

    Get PDF
    Caterpillar feeding induces direct and indirect defences in brassicaceous plants. This study focused on the role of the octadecanoid pathway in induced indirect defence in Brassica oleracea. The effect of induction by exogenous application of jasmonic acid (JA) on the responses of Brussels sprouts plants and on host-location behaviour of associated parasitoid wasps was studied. Feeding by the biting–chewing herbivores Pieris rapae and Plutella xylostella resulted in significantly increased endogenous levels of JA, a central component in the octadecanoid signalling pathway that mediates induced plant defence. The levels of the intermediate 12-oxophyto-dienoic acid (OPDA) were significantly induced only after P. rapae feeding. Three species of parasitoid wasps, Cotesia glomerata, C. rubecula, and Diadegma semiclausum, differing in host range and host specificity, were tested for their behavioural responses to volatiles from herbivore-induced, JA-induced, and non-induced plants. All three species were attracted to volatiles from JA-induced plants compared with control plants; however, they preferred volatiles from herbivore-induced plants over volatiles from JA-induced plants. Attraction of C. glomerata depended on both timing and dose of JA application. JA-induced plants produced larger quantities of volatiles than herbivore-induced and control plants, indicating that not only quantity, but also quality of the volatile blend is important in the host-location behaviour of the wasps

    Methyl jasmonate-elicited herbivore resistance: does MeJA function as a signal without being hydrolyzed to JA?

    Get PDF
    Treatment with methyl jasmonate (MeJA) elicits herbivore resistance in many plant species and over-expression of JA carboxyl methyltransferase (JMT) constitutively increases JA-induced responses in Arabidopsis. When wild-type (WT) Nicotiana attenuata plants are treated with MeJA, a rapid transient endogenous JA burst is elicited, which in turn increases levels of nicotine and trypsin proteinase inhibitors (TPIs) and resistance to larvae of the specialist herbivore, Manduca sexta. All of these responses are impaired in plants silenced in lipoxygenase 3 expression (asLOX3) but are restored to WT levels by MeJA treatment. Whether these MeJA-induced responses are directly elicited by MeJA or by its cleavage product, JA, is unknown. Using virus-induced gene silencing (VIGS), we silenced MeJA-esterase (NaMJE) expression and found this gene responsible for most of the MeJA-cleaving activity in N. attenuata protein extracts. Silencing NaMJE in asLOX3, but not in WT plants, significantly reduced MeJA-induced nicotine levels and resistance to M. sexta, but not TPI levels. MeJA-induced transcript levels of threonine deaminase (NaTD) and phenylalanine ammonia lyase (NaPAL1) were also decreased in VIGS MJE (asLOX3) plants. Finally the performance of M. sexta larvae that fed on plants treated with JA or MeJA demonstrated that silencing NaMJE inhibited MeJA-induced but not JA-induced resistance in asLOX3 plants. From these results, we conclude that the resistance elicited by MeJA treatment is directly elicited not by MeJA but by its de-methylated product, JA

    The Supply Side Determinants of Territory and Conflict

    Get PDF
    What determines the geographic extent of territory? We microfound and extend Boulding’s “Loss of Strength Gradient” to predict the extensive and intensive margins of conflict across space. We show how economies of scale in the production of violence and varying costs of projecting violence at a distance combine to affect the geographic distribution of conflict and territory. We test and probe the boundaries of this model in an experiment varying the fixed costs of conflict entry. As predicted, higher fixed costs increase the probability of exclusive territories; median behavior closely tracks equilibrium predictions in all treatments

    How Plants Sense Wounds: Damaged-Self Recognition Is Based on Plant-Derived Elicitors and Induces Octadecanoid Signaling

    Get PDF
    Background: Animal-derived elicitors can be used by plants to detect herbivory but they function only in specific insect– plant interactions. How can plants generally perceive damage caused by herbivores? Damaged-self recognition occurs when plants perceive molecular signals of damage: degraded plant molecules or molecules localized outside their original compartment. Methodology/Principal Findings: Flame wounding or applying leaf extract or solutions of sucrose or ATP to slightly wounded lima bean (Phaseolus lunatus) leaves induced the secretion of extrafloral nectar, an indirect defense mechanism. Chemically related molecules that would not be released in high concentrations from damaged plant cells (glucose, fructose, salt, and sorbitol) did not elicit a detectable response, excluding osmotic shock as an alternative explanation. Treatments inducing extrafloral nectar secretion also enhanced endogenous concentrations of the defense hormone jasmonic acid (JA). Endogenous JA was also induced by mechanically damaging leaves of lima bean, Arabidopsis, maize, strawberry, sesame and tomato. In lima bean, tomato and sesame, the application of leaf extract further increased endogenous JA content, indicating that damaged-self recognition is taxonomically widely distributed. Transcriptomic patterns obtained with untargeted 454 pyrosequencing of lima bean in response to flame wounding or the application of leaf extract or JA were highly similar to each other, but differed from the response to mere mechanical damage. W
    corecore