Enantiomeric conservation of the male‐produced sex pheromone facilitates monitoring of threatened European hermit beetles (Osmoderma spp.)

Hermit beetles of the genus Osmoderma (Coleoptera: Scarabaeidae: Cetoniinae) are known for their fruity odour, which is released in large amounts by males. Two species of the genus occur in Europe, the eastern Osmoderma barnabita (Motschulsky) and the western Osmoderma eremita (Scopoli). Previous studies on Swedish populations of O. eremita showed that the compound responsible for the characteristic scent, γ‐decalactone, functions as a sex pheromone for the attraction of conspecific females. Male O. eremita only release the (R)‐enantiomer of the lactone, and both sexes are anosmic to the opposite enantiomer. As the distribution areas of the two hermit beetle species partly overlap, it may be expected that they use different enantiomeric compositions of γ‐decalactone as pheromones to promote species discrimination. This paper reports on the identification of the sex pheromone of O. barnabita. Surprisingly, males from a Polish population produce only the (R)‐enantiomer of γ‐decalactone, and conspecific females show equal attraction to the (R)‐enantiomer and a racemic mixture of the compound, indicating that O. barnabita is anosmic to the (S)‐enantiomer, similarly to what was observed for O. eremita. A mtDNA sequence analysis of the cytochrome oxidase subunit I gene of Polish and Swedish beetles confirmed their taxonomical status as O. barnabita and O. eremita, respectively, with an average sequence divergence of 10.5% between beetles from the two studied areas. Although genetic data suggest that these species diverged several million years ago, they still rely on the same enantiomer of γ‐decalactone for mate finding. Thus, the male‐produced pheromone in Osmoderma spp. may be regarded as a territorial signal being exploited by females, rather than a cue for determining species identity. Our data show that the same compound can be used to facilitate monitoring of both beetle species, which are considered indicator species of the species‐rich fauna of saproxylic insects in Europe.     

EVIDENCE FOR IMPACTS OF NONINDIGENOUS MACROALGAE: A META‐ANALYSIS OF EXPERIMENTAL FIELD STUDIES1

Invasions by nonindigenous macroalgal species (NIMS) potentially cause severe impacts on native species. We conducted a meta‐analysis of 18 field‐based manipulative experiments to quantify the direction and magnitude of impacts (Hedges effect size d, hereafter ES). We found significant small‐to‐medium negative effects on “macrophyte abundance” (cover, biomass of native taxa; ES_cumulative = ?0.30) and medium‐to‐large negative effects on “macrophyte assemblages” (richness, diversity, total abundance; ES_cumulative = ?0.70). In contrast, ES_cumulative were not significant for “macrophyte processes” (growth, mortality; ES_cumulative = ?0.39), “animal abundance” (densities; ES_cumulative = ?0.13), or “animal assemblages” (richness, diversity; ES_cumulative = 0.75). The nonsignificant effect sizes were characterized by low sample sizes and should be interpreted with caution. Three study‐specific effect sizes were particularly large (cumulative are likely biased toward larger effects because only the most conspicuous NIMS have been tested and because nonsignificant results are less likely to be published. To better understand the impacts of NIMS, more manipulative experiments are needed, testing more species and under contrasting environmental conditions. Future studies should include procedural control treatments and report the abundance of the NIMS to avoid ambiguous interpretations. In conclusion, current experimental evidence shows that NIMS have, on average, small‐to‐large negative impacts on native plant species and assemblages. It is possible that these effects can result in severe consequences when accumulated over long time periods and large spatial scales.     

某坦克部队外训期间的膳食营养调查

目的:了解坦克部队官兵在野外驻训期间的膳食营养状况,为指导合理膳食提供参考依据。方法:膳食调查采用称重法,能量消耗采用生活观察法,体格检查指标包括体重和皮褶厚度。结果:每日人均禽肉、鱼虾、蔬菜等摄入水平未达到"军人食物定量"标准,而植物油摄入量则超过军标要求;VB1、VC、铁、锌、硒、碘等摄入量未达到"军人营养素供给量"标准要求;三大产能营养素供能比例不合理,脂肪摄入偏高,碳水化合物偏低;多数官兵野外驻训7 d后体重和皮褶厚度降低。结论:该部队在野外驻训期间膳食结构不够合理,部分营养素摄入量未达到军标要求,应调整膳食结构,改善官兵的营养状况。     

A Quantitative Measure of Field Illumination

In this paper, we describe a statistically based algorithm to quantify the uniformity of illumination in an optical light microscopy imaging system that outputs a single quality factor (QF) score. The importance of homogeneous field illumination in quantitative light microscopy is well understood and often checked. However, there is currently no standard automatic quantitative measure of the uniformity of the field illumination. Images from 89 different laser-scanning confocal microscopes (LSCMs), which were collected as part of an international study on microscope quality assessment, were used as a “training” set to build the algorithm. To validate the algorithm and verify its robustness, images from 33 additional microscopes, including LSCM and wide-field (WF) microscopes, were used. The statistical paradigm used for developing the quality scoring scale was a regression approach to supervised learning. Three intensity profiles across each image—2 corner-to-corner diagonals and a center horizontal—were used to generate pixel-intensity data. All of the lines passed through the center of the image. The intensity profile data then were converted into a single-field illumination QF score in the range of 0–100, with 0 having extreme variation, and therefore, essentially unusable, and 100 having no deviation, i.e., straight lines with a constant uniform intensity. Empirically, a QF ≥ 83 was determined to be the minimum acceptable value based on manufacturer acceptance tests and reasonably achievable values. This new QF is an invaluable metric to ascertain objectively and easily the uniformity of illumination quality, provide a traceable reference for monitoring field uniformity over time, and make a direct comparison among different microscopes. The QF can also be used as an indicator of system failure and the need for alignment or service of the instrument.     

Cell competition: Winning out by losing notch

Cell competition where ‘loser’ cells are eliminated by neighbors with higher fitness is a widespread phenomenon in development. However, a growing body of evidence argues cells with somatic mutations compete with their wild type counterparts in the earliest stages of cancer development. Recent studies have begun to shed light on the molecular and cellular mechanisms that alter the competitiveness of cells carrying somatic mutations in adult tissues. Cells with a ‘winner’ phenotype create clones which may expand into extensive fields of mutant cells within normal appearing epithelium, favoring the accumulation of further genetic alterations and the evolution of cancer. Here we focus on how mutations which disrupt the Notch signaling pathway confer a ‘super competitor’ status on cells in squamous epithelia and consider the broader implications for cancer evolution.     

Topographical Estimation of Visual Population Receptive Fields by fMRI

Visual cortex is retinotopically organized so that neighboring populations of cells map to neighboring parts of the visual field. Functional magnetic resonance imaging allows us to estimate voxel-based population receptive fields (pRF), i.e., the part of the visual field that activates the cells within each voxel. Prior, direct, pRF estimation methods¹ suffer from certain limitations: 1) the pRF model is chosen a-priori and may not fully capture the actual pRF shape, and 2) pRF centers are prone to mislocalization near the border of the stimulus space. Here a new topographical pRF estimation method² is proposed that largely circumvents these limitations. A linear model is used to predict the Blood Oxygen Level-Dependent (BOLD) signal by convolving the linear response of the pRF to the visual stimulus with the canonical hemodynamic response function. PRF topography is represented as a weight vector whose components represent the strength of the aggregate response of voxel neurons to stimuli presented at different visual field locations. The resulting linear equations can be solved for the pRF weight vector using ridge regression³, yielding the pRF topography. A pRF model that is matched to the estimated topography can then be chosen post-hoc, thereby improving the estimates of pRF parameters such as pRF-center location, pRF orientation, size, etc. Having the pRF topography available also allows the visual verification of pRF parameter estimates allowing the extraction of various pRF properties without having to make a-priori assumptions about the pRF structure. This approach promises to be particularly useful for investigating the pRF organization of patients with disorders of the visual system.     

Effects of sampling method on foliar δ13C of Leymus chinensis at different scales

Stable carbon isotope composition (δ¹³C) usually shows a negative relationship with precipitation at a large scale. We hypothesized that sampling method affects foliar δ¹³C and its response pattern to precipitation. We selected 11 sites along a precipitation gradient in Inner Mongolia and collected leaves of Leymus chinensis with five or six replications repeatedly in each site from 2009 to 2011. Additionally, we collected leaves of L. chinensis separately from two types of grassland (grazed and fenced) in 2011. Foliar δ¹³C values of all samples were measured. We compared the patterns that foliar δ¹³C to precipitation among different years or different sample sizes, the differences of foliar δ¹³C between grazed and fenced grassland. Whether actual annual precipitation (AAP) or mean annual precipitation (MAP), it was strongly correlated with foliar δ¹³C every year. Significant difference was found between the slopes of foliar δ¹³C to AAP and MAP every year, among the slopes of foliar δ¹³C to AAP from 2009 to 2011. The more samples used at each site the lower and convergent P‐values of the linear regression test between foliar δ¹³C and precipitation. Furthermore, there was significant lower foliar δ¹³C value in presence of grazed type than fenced type grassland. These findings provide evidence that there is significant effect of sampling method to foliar δ¹³C and its response pattern to precipitation of L. chinensis. Our results have valuable implications in methodology for future field sampling studies.     

Effects of the Epichloë fungal endophyte symbiosis with Schedonorus pratensis on host grass invasiveness

Initial studies of grass–endophyte mutualisms using Schedonorus arundinaceus cultivar Kentucky‐31 infected with the vertically transmitted endophyte Epichloë coenophiala found strong, positive endophyte effects on host‐grass invasion success. However, more recent work using different cultivars of S. arundinaceus has cast doubt on the ubiquity of this effect, at least as it pertains to S. arundinaceus–E. coenophiala. We investigated the generality of previous work on vertically transmitted Epichloë‐associated grass invasiveness by studying a pair of very closely related species: S. pratensis and E. uncinata. Seven cultivars of S. pratensis and two cultivars of S. arundinaceus that were developed with high‐ or low‐endophyte infection rate were broadcast seeded into 2 × 2‐m plots in a tilled, old‐field grassland community in a completely randomized block design. Schedonorus abundance, endophyte infection rate, and co‐occurring vegetation were sampled 3, 4, 5, and 6 years after establishment, and the aboveground invertebrate community was sampled in S. pratensis plots 3 and 4 years after establishment. Endophyte infection did not enable the host grass to achieve high abundance in the plant community. Contrary to expectations, high‐endophyte S. pratensis increased plant richness relative to low‐endophyte cultivars. However, as expected, high‐endophyte S. pratensis marginally decreased invertebrate taxon richness. Endophyte effects on vegetation and invertebrate community composition were inconsistent among cultivars and were weaker than temporal effects. The effect of the grass–Epichloë symbiosis on diversity is not generalizable, but rather specific to species, cultivar, infection, and potentially site. Examining grass–endophyte systems using multiple cultivars and species replicated among sites will be important to determine the range of conditions in which endophyte associations benefit host grass performance and have subsequent effects on co‐occurring biotic communities.