Bornean caterpillar (Lepidoptera) constructs cocoon from Vatica rassak (Dipterocarpaceae) resin containing multiple deterrent compounds

Many Lepidoptera larvae use pieces of vegetation bound with silk to construct or disguise their cocoons. Here we report the first known case of a caterpillar building its cocoon entirely out of fragments of resin, broken away from sheets of dried resin on the trunk of a tree and held together with silk. The behaviour of the larva (possibly Negritothripa sp. in the Nolidae), from the Kinabatangan Wildlife Sanctuary in Sabah, Borneo, is described. The cocoon was constructed on the trunk of Vatica rassak (Dipterocarpaceae). Analysis of resin from the cocoon, using gas chromatography-mass spectrometry, revealed a complex mixture of 260 components, dominated by sesquiterpenes and triterpenes. Many of these compounds have defensive properties, protecting the tree from herbivores and fungi. The larva appears to have evolved an elaborate and possibly unique behaviour, allowing it to harness the defensive properties of the resin to protect its pupa from predators and/or entomopathogenic fungi.     

Genome-wide association study identifies susceptibility loci for dengue shock syndrome at MICB and PLCE1

Hypovolemic shock (dengue shock syndrome (DSS)) is the most common life-threatening complication of dengue. We conducted a genome-wide association study of 2,008 pediatric cases treated for DSS and 2,018 controls from Vietnam. Replication of the most significantly associated markers was carried out in an independent Vietnamese sample of 1,737 cases and 2,934 controls. SNPs at two loci showed genome-wide significant association with DSS. We identified a susceptibility locus at MICB (major histocompatibility complex (MHC) class I polypeptide-related sequence B), which was within the broad MHC region on chromosome 6 but outside the class I and class II HLA loci (rs3132468, P(meta) = 4.41 × 10(-11), per-allele odds ratio (OR) = 1.34 (95% confidence interval: 1.23-1.46)). We identified associated variants within PLCE1 (phospholipase C, epsilon 1) on chromosome 10 (rs3765524, P(meta) = 3.08 × 10(-10), per-allele OR = 0.80 (95% confidence interval: 0.75-0.86)). We identify two loci associated with susceptibility to DSS in people with dengue, suggesting possible mechanisms for this severe complication of dengue.     

On SETAR non‐linearity and forecasting

We compare linear autoregressive (AR) models and self‐exciting threshold autoregressive (SETAR) models in terms of their point forecast performance, and their ability to characterize the uncertainty surrounding those forecasts, i.e. interval or density forecasts. A two‐regime SETAR process is used as the data‐generating process in an extensive set of Monte Carlo simulations, and we consider the discriminatory power of recently developed methods of forecast evaluation for different degrees of non‐linearity. We find that the interval and density evaluation methods are unlikely to show the linear model to be deficient on samples of the size typical for macroeconomic data. Copyright © 2003 John Wiley & Sons, Ltd.     

Conceptual Barriers to Progress Within Evolutionary Biology

In spite of its success, Neo-Darwinism is faced with major conceptual barriers to further progress, deriving directly from its metaphysical foundations. Most importantly, neo-Darwinism fails to recognize a fundamental cause of evolutionary change, “niche construction”. This failure restricts the generality of evolutionary theory, and introduces inaccuracies. It also hinders the integration of evolutionary biology with neighbouring disciplines, including ecosystem ecology, developmental biology, and the human sciences. Ecology is forced to become a divided discipline, developmental biology is stubbornly difficult to reconcile with evolutionary theory, and the majority of biologists and social scientists are still unhappy with evolutionary accounts of human behaviour. The incorporation of niche construction as both a cause and a product of evolution removes these disciplinary boundaries while greatly generalizing the explanatory power of evolutionary theory.

Widespread local house-sparrow extinctions

House-sparrow populations have declined sharply in Western Europe in recent decades, but the reasons for this decline have yet to be identified, despite intense public interest in the matter. Here we use a combination of field experimentation, genetic analysis and demographic data to show that a reduction in winter food supply caused by agricultural intensification is probably the principal explanation for the widespread local extinctions of rural house-sparrow populations in southern England. We show that farmland populations exhibit fine-level genetic structuring and that some populations are unable to sustain themselves (sinks), whereas others act as sources.     

The 'solar model problem' solved by the abundance of neon in nearby stars

The interior structure of the Sun can be studied with great accuracy using observations of its oscillations, similar to seismology of the Earth. Precise agreement between helioseismological measurements and predictions of theoretical solar models has been a triumph of modern astrophysics. A recent downward revision by 25-35 per cent of the solar abundances of light elements such as C, N, O and Ne (ref. 2) has, however, broken this accordance: models adopting the new abundances incorrectly predict the depth of the convection zone, the depth profiles of sound speed and density, and the helium abundance. The discrepancies are far beyond the uncertainties in either the data or the model predictions. Here we report neon-to-oxygen ratios measured in a sample of nearby solar-like stars, using their X-ray spectra. The abundance ratios are all very similar and substantially larger than the recently revised solar value. The neon abundance in the Sun is quite poorly determined. If the Ne/O abundance in these stars is adopted for the Sun, the models are brought back into agreement with helioseismology measurements.     

Convective-region geometry as the cause of Uranus' and Neptune's unusual magnetic fields

The discovery of Uranus' and Neptune's non-dipolar, non-axisymmetric magnetic fields destroyed the picture--established by Earth, Jupiter and Saturn--that planetary magnetic fields are dominated by axial dipoles. Although various explanations for these unusual fields have been proposed, the cause of such field morphologies remains unexplained. Planetary magnetic fields are generated by complex fluid motions in electrically conducting regions of the planets (a process known as dynamo action), and so are intimately linked to the structure and evolution of planetary interiors. Determining why Uranus and Neptune have different field morphologies is not only critical for studying the interiors of these planets, but also essential for understanding the dynamics of magnetic-field generation in all planets. Here we present three-dimensional numerical dynamo simulations that model the dynamo source region as a convecting thin shell surrounding a stably stratified fluid interior. We show that this convective-region geometry produces magnetic fields similar in morphology to those of Uranus and Neptune. The fields are non-dipolar and non-axisymmetric, and result from a combination of the stable fluid's response to electromagnetic stress and the small length scales imposed by the thin shell.     

The DNA sequence and biology of human chromosome 19

Chromosome 19 has the highest gene density of all human chromosomes, more than double the genome-wide average. The large clustered gene families, corresponding high G + C content, CpG islands and density of repetitive DNA indicate a chromosome rich in biological and evolutionary significance. Here we describe 55.8 million base pairs of highly accurate finished sequence representing 99.9% of the euchromatin portion of the chromosome. Manual curation of gene loci reveals 1,461 protein-coding genes and 321 pseudogenes. Among these are genes directly implicated in mendelian disorders, including familial hypercholesterolaemia and insulin-resistant diabetes. Nearly one-quarter of these genes belong to tandemly arranged families, encompassing more than 25% of the chromosome. Comparative analyses show a fascinating picture of conservation and divergence, revealing large blocks of gene orthology with rodents, scattered regions with more recent gene family expansions and deletions, and segments of coding and non-coding conservation with the distant fish species Takifugu.     

Evolutionary genetics: Ambiguous role of CCR5 in Y. pestis infection

Mecsas and colleagues suggest that a deficiency in the chemokine receptor CCR5 in humans is unlikely to confer protection against plague, based on their study of Yersinia pestis infection in Ccr5-deficient mice. They were testing the hypothesis that a mutation in the CCR5 gene, frequently found in Caucasians, may have been selected for in the past because it provided protection against (bubonic) plague; the mutation, called CCR5Delta32, is characterized by a 32-base-pair deletion. We have also tested this hypothesis by using Y. pestis infection in mice and, in addition, we have done phagocytosis experiments with macrophages from wild-type and Ccr5-deficient mice. Although, like Mecsas et al., we did not see any difference in the survival of the two groups of mice, we did find that there was a significantly reduced uptake of Y. pestis by Ccr5-deficient macrophages in vitro. Our results indicate that the role of Ccr5 in Y. pestis infection may therefore be more complex than previously thought.