United in adversity: Aridity and cold influence aggregation behaviour in a social lizard,Egernia stokesii

Sociality has evolved independently many times in a diverse array of animal taxa. While sociality in some invertebrates, birds and mammals is relatively well understood, complex social behaviour in Squamate reptiles is a comparatively recent discovery. The extent to which social behaviour is phylogenetically constrained, or free to respond to environmental conditions is a key question in understanding sociality. We sampled 74 aggregations involving 137 individuals of a social lizard (Egernia stokesii) from 13 sites across a 96 250 km² area showing a wide range of environmental conditions. Over all locations, 70% of the lizards were found in aggregations, supporting the previous suggestion that aggregation in this species is phylogenetically constrained. However, the size of aggregations was negatively related to spatial variation in aridity and daily variation in maximum temperature, suggesting that social behaviour also varied in response to harsh environmental conditions. Lizards aggregated more in arid areas and on cold days. Our results show that it is overly simplistic to regard social behaviour in E. stokesii as either phylogenetically constrained or environmentally determined. A more nuanced appreciation of the extent to which social behaviour is free to vary in response to environmental conditions improves our understanding of social behaviour in Squamate reptiles.     

Historical and philosophical perspectives on the study of developmental bias

Throughout the recent history of research at the intersection of evolution and development, notions such as developmental constraint, evolutionary novelty, and evolvability have been prominent, but the term “developmental bias” has scarcely been used. And one may even doubt whether a unique and principled definition of bias is possible. I argue that the concept of developmental bias can still play a vital scientific role by means of setting an explanatory agenda that motivates investigation and guides the formulation of integrative explanatory frameworks. Less crucial is a definition that would classify patterns of phenotypic variation and unify variational patterns involving different traits and taxa as all being “bias.” Instead, what we should want is a concept that generates intellectual identity across various researchers, and that unites the diverse fields and approaches relevant to the study of developmental bias, from paleontology to behavioral biology. I point to some advantages of conducting research specifically under the label of “developmental bias,” compared with employing other, more common terms such as “evolvability.”     

Familiar soil conditions help Pinus ponderosa seedlings cope with warming and drying climate

Changes in temperature and moisture as a result of climate forcing can impact performance of planted trees. Tree performance may also be sensitive to new soil conditions, for example, brought about by seeds germinating in soils different from those colonized by ancestral populations. Such “edaphic constraint” may occur with natural migration or human‐assisted movement. Pinus ponderosa seedlings, sourced from one location (“home” site), were grown across a field environmental gradient in either their original home soil or in soils from two different “away” sites. Seedlings were inoculated with site‐specific soil organisms by germinating seeds in living soil. After 6 months, the inoculated seedlings were transplanted into sterilized soils from the home or away sites. This experimental design allowed us to uncouple the importance of abiotic and biotic soil properties and test (1) how biotic and abiotic soil properties interact with climate to influence plant growth and stress tolerance, and (2) the role of soil biota in facilitating growth in novel environments. Seedlings grew least in hotter and drier away sites with away soil biota. Home soil biota ameliorated negative impacts on growth of hotter and drier away sites. Measurements of photosynthetic rate, stomatal conductance, and chlorophyll florescence (Fv/Fm) suggest that edaphic constraint reduced growth by increasing tree water stress. Results suggest that success of Ponderosa pine plantings into warming environments will be enhanced by pre‐inoculation with native soil biota of the seed source.     

Rapid reversal of a potentially constraining genetic covariance between leaf and flower traits in Silene latifolia

Genetic covariance between two traits generates correlated responses to selection, and may either enhance or constrain adaptation. Silene latifolia exhibits potentially constraining genetic covariance between specific leaf area (SLA) and flower number in males. Flower number is likely to increase via fecundity selection but the correlated increase in SLA increases mortality, and SLA is under selection to decrease in dry habitats. We selected on trait combinations in two selection lines for four generations to test whether genetic covariance could be reduced without significantly altering trait means. In one selection line, the genetic covariance changed sign and eigenstructure changed significantly, while in the other selection line eigenstructure remained similar to the control line. Changes in genetic variance–covariance structure are therefore possible without the introduction of new alleles, and the responses we observed suggest that founder effects and changes in frequency of alleles of major effect may be acting to produce the changes.     

On computation of semiparametric maximum likelihood estimators with shape constraints

Large sample theory of semiparametric models based on maximum likelihood estimation (MLE) with shape constraint on the nonparametric component is well studied. Relatively less attention has been paid to the computational aspect of semiparametric MLE. The computation of semiparametric MLE based on existing approaches such as the expectation‐maximization (EM) algorithm can be computationally prohibitive when the missing rate is high. In this paper, we propose a computational framework for semiparametric MLE based on an inexact block coordinate ascent (BCA) algorithm. We show theoretically that the proposed algorithm converges. This computational framework can be applied to a wide range of data with different structures, such as panel count data, interval‐censored data, and degradation data, among others. Simulation studies demonstrate favorable performance compared with existing algorithms in terms of accuracy and speed. Two data sets are used to illustrate the proposed computational method. We further implement the proposed computational method in R package BCA1SG , available at CRAN.     

玉米灵芝菌粮营养成分及加工特性变化研究

玉米作为主要的杂粮谷物,营养价值高,维生素、膳食纤维等含量丰富,可以预防多种亚健康疾病,受到市场追捧。但是玉米粉营养结构不均衡、加工性差,限制其应用。有研究表明,微生物发酵技术可以改善谷物的营养成分、大分子物质结构和加工特性。基于此,利用灵芝固态发酵玉米,得到玉米灵芝菌粮（简称菌粮）,从营养成分、大分子物质结构和加工特性3个方面对其进行评价。结果显示,与未发酵玉米相比,菌粮中碳水化合物、蛋白质含量分别提高了748%、28.00%,且蛋白质的氨基酸评分提高,而脂肪含量降低了52.56%;维生素C、核黄素和烟酸含量均显著提高（P<0.05）,分别提高了56.19%、73.91%和20.27%,且玉米中缺乏的硫胺素在菌粮中被检测到;菌粮中各类淀粉和纤维的含量也发生了显著变化（P<0.05）,淀粉、支链淀粉含量分别降低了11.17%、34.70%,直链淀粉含量提高了26.66%,粗纤维、不溶性膳食纤维含量分别降低了21.07%、21.47%,可溶性膳食纤维含量提高了13.57%;菌粮粉粘度降低,水溶性指数提高,吸水性指数和溶胀力降低;此外,与灵芝子实体相比,菌粮中灵芝三萜和灵芝酸含量均显著提高（P<0.05）,分别为灵芝子实体的1.68和2.07倍。灵芝固态发酵玉米得到的玉米灵芝菌粮,营养结构更加均衡,功能活性提高,具有更高的营养价值;大分子物质结构发生改变,加工特性得到改善,冲调特性更好。研究结果为食用菌发酵改良谷物特性的研究提供了参考和指导。     

双斑蟋营养成分分析及评价

由于具有较好的营养价值以及较高的食物转化效率,食用昆虫特别是蟋蟀受到普遍关注。在双斑蟋（Gryllus bimaculatus,GB）营养成分测定的基础上,对比家蟋（Acheta domesticus,AD）和黑蟋（Gryllus testaceus,GT）的营养及含量,分析评价了双斑蟋的使用价值。结果显示：双斑蟋水分含量71.0%、粗蛋白含量58.60%（干重）、粗脂肪含量28.90%（干重）、粗纤维含量7.23%（干重）、灰分4.93%（干重）;蛋白含量与黑蟋相当而高于家蟋,粗脂肪和灰分含量要高于家蟋和黑蟋;双斑蟋含有17种氨基酸,总氨基酸含量51.03%（干重）,必需氨基酸含量24.76%（干重）、占总氨基酸的48.3%,氨基酸含量低于其他两种蟋蟀;双斑蟋中常量元素含量最高的为钾（6 416 mg/kg,干重）、含量最低的是钙（92 mg/kg,干重）,微量元素中锌含量较高（241 mg/kg,干重）;双斑蟋油脂中不饱和脂肪酸的相对含量为65.33%,以亚油酸（37.05%）和油酸（25.86%）为主、饱和脂肪酸以棕榈酸（25.44%）和硬脂酸（8.74%）为主。双斑蟋的脂肪酸组成、含量与家蟋相近,而与黑蟋的脂肪酸组成差别较大,三种蟋蟀中含量最高的饱和脂肪酸为棕榈酸,而含量最高的不饱和酸为亚油酸。结果表明,双斑蟋的必需氨基酸组成符合FAO/WHO推荐的氨基酸构成比例的蛋白条件,具有较高的营养价值和食用价值。