Method for Prioritizing Urban Pesticides for Monitoring

Environmental Monitoring Branch (EM) is to monitor pesticide residues in surface waters with urban runoff inputs. Recent monitoring efforts have identified urban runoff as a major contributor of pesticides to California surface waters (Ensminger et al., 2012). Pesticide use is i

The influence of maternal glucocorticoids on offspring phenotype in high-and low-risk environments

Elevated maternal glucocorticoid levels during gestation can lead to phenotypic changes in offspring via maternal effects. Although such effects have traditionally been considered maladaptive, maternally derived glucocorticoids may adaptively prepare offspring for their future environment depending upon the correlation between maternal and offspring environments. Nevertheless, relatively few studies test the effects of prenatal glucocorticoid exposure across multiple environments. We tested the potential for ecologically relevant increases in maternal glucocorticoids in the eastern fence lizard (Sceloporus undulatus) to induce adaptive phenotypic changes in offspring exposed to high or low densities of an invasive fire ant predator. Maternal treatment had limited effects on offspring morphology and behavior at hatching, but by 10 days of age, we found maternal treatment interacted with offspring environment to alter anti-predator behaviors. We did not detect differences in early-life survival based on maternal treatment or offspring environment. Opposing selection on anti-predator behaviors from historic and novel invasive predators may confound the potential of maternal glucocorticoids to adaptively influence offspring behavior. Our test of the phenotypic outcomes of transgenerational glucocorticoid effects across risk environments provides important insight into the context-specific nature of this phenomenon and the importance of understanding both current and historic evolutionary pressures

“Economic man” in cross-cultural perspective: Behavioral experiments in 15 small-scale societies

Researchers from across the social sciences have found consistent deviations from the predictions of the canonical model of self-interest in hundreds of experiments from around the world. This research, however, cannot determine whether the uniformity results from universal patterns of human behavior or from the limited cultural variation available among the university students used in virtually all prior experimental work. To address this, we undertook a cross-cultural study of behavior in ultimatum, public goods, and dictator games in a range of small-scale societies exhibiting a wide variety of economic and cultural conditions. We found, first, that the canonical model – based on self-interest – fails in all of the societies studied. Second, our data reveal substantially more behavioral variability across social groups than has been found in previous research. Third, group-level differences in economic organization and the structure of social interactions explain a substantial portion of the behavioral variation across societies: the higher the degree of market integration and the higher the payoffs to cooperation in everyday life, the greater the level of prosociality expressed in experimental games. Fourth, the available individual-level economic and demographic variables do not consistently explain game behavior, either within or across groups. Fifth, in many cases experimental play appears to reflect the common interactional patterns of everyday life

Homo Æqualis: A Cross-Society Experimental Analysis of Three Bargaining Games

Data from three bargaining games-the Dictator Game, the Ultimatum Game, and the Third-Party Punishment Game-played in 15 societies are presented. The societies range from US undergraduates to Amazonian, Arctic, and African hunter-gatherers. Behaviour within the games varies markedly across societies. The paper investigates whether this behavioural diversity can be explained solely by variations in inequality aversion. Combining a single parameter utility function with the notion of subgame perfection generates a number of testable predictions. While most of these are supported, there are some telling divergences between theory and data: uncertainty and preferences relating to acts of vengeance may have influenced play in the Ultimatum and Third-Party Punishment Games; and a few subjects used the games as an opportunity to engage in costly signalling.

DNA breaks and chromosomal aberrations arise when replication meets base excision repair

Exposures that methylate DNA potently induce DNA double-strand breaks (DSBs) and chromosomal aberrations, which are thought to arise when damaged bases block DNA replication. Here, we demonstrate that DNA methylation damage causes DSB formation when replication interferes with base excision repair (BER), the predominant pathway for repairing methylated bases. We show that cells defective in the N-methylpurine DNA glycosylase, which fail to remove N-methylpurines from DNA and do not initiate BER, display strongly reduced levels of methylation-induced DSBs and chromosomal aberrations compared with wild-type cells. Also, cells unable to generate single-strand breaks (SSBs) at apurinic/apyrimidinic sites do not form DSBs immediately after methylation damage. In contrast, cells deficient in x-ray cross-complementing protein 1, DNA polymerase β, or poly (ADP-ribose) polymerase 1 activity, all of which fail to seal SSBs induced at apurinic/apyrimidinic sites, exhibit strongly elevated levels of methylation-induced DSBs and chromosomal aberrations. We propose that DSBs and chromosomal aberrations after treatment with N-alkylators arise when replication forks collide with SSBs generated during BER

Costly Punishment Across Human Societies

Recent behavioral experiments aimed at understanding the evolutionary foundations of human cooperation have suggested that a willingness to engage in costly punishment, even in one-shot situations, may be part of human psychology and a key element in understanding our sociality. However, because most experiments have been confined to students in industrialized societies, generalizations of these insights to the species have necessarily been tentative. Here, experimental results from 15 diverse populations show that (i) all populations demonstrate some willingness to administer costly punishment as unequal behavior increases, (ii) the magnitude of this punishment varies substantially across populations, and (iii) costly punishment positively covaries with altruistic behavior across populations. These findings are consistent with models of the gene-culture coevolution of human altruism and further sharpen what any theory of human cooperation needs to explain

Markets, Religion, Community Size, and the Evolution of Fairness and Punishment

Large-scale societies in which strangers regularly engage in mutually beneficial transactions are puzzling. The evolutionary mechanisms associated with kinship and reciprocity, which underpin much of primate sociality, do not readily extend to large unrelated groups. Theory suggests that the evolution of such societies may have required norms and institutions that sustain fairness in ephemeral exchanges. If that is true, then engagement in larger-scale institutions, such as markets and world religions, should be associated with greater fairness, and larger communities should punish unfairness more. Using three behavioral experiments administered across 15 diverse populations, we show that market integration (measured as the percentage of purchased calories) positively covaries with fairness while community size positively covaries with punishment. Participation in a world religion is associated with fairness, although not across all measures. These results suggest that modern prosociality is not solely the product of an innate psychology, but also reflects norms and institutions that have emerged over the course of human history

γH2AX foci analysis for monitoring DNA double-strand break repair: Strengths, limitations and optimization

DNA double-strand breaks (DSBs) represent an important radiation-induced lesion and impaired DSB repair provides the best available correlation with radiosensitivity. Physical techniques for monitoring DSB repair require high, non-physiological doses and cannot reliably detect subtle defects. One outcome from extensive research into the DNA damage response is the observation that H2AX, a variant form of the histone H2A, undergoes extensive phosphorylation at the DSB, creating γH2AX foci that can be visualised by immunofluorescence. There is a close correlation between γH2AX foci and DSB numbers and between the rate of foci loss and DSB repair, providing a sensitive assay to monitor DSB repair in individual cells using physiological doses. However, γH2AX formation can occur at single-stranded DNA regions which arise during replication or repair and thus does not solely correlate with DSB formation. Here, we present and discuss evidence that following exposure to ionising radiation, γH2AX foci analysis can provide a sensitive monitor of DSB formation and repair and describe techniques to optimise the analysis. We discuss the limitations and benefits of the technique, enabling the procedure to be optimally exploited but not misused

Reply to van Hoorn: Converging lines of evidence

We agree with the comments by van Hoorn (1) on our critique (2): testing causal hypotheses about human behavior is a challenge (1, 3). Making progress requires specifying alternative hypotheses and then testing these hypotheses using diverse and converging lines of evidence. We have defended the hypothesis that social norms, which culturally coevolved with the institutions of large-scale societies including markets, influence economic decision-making. This hypothesis emerged from a larger set that we developed both at the outset of our project and as we went along. Our interdisciplinary team’s initial list of hypotheses included the idea that experimental games might spark an innate reciprocity module that would yield little variation across populations