Losses of female song with changes from tropical to temperate breeding in the New World blackbirds

Birds in which both sexes produce complex songs are thought to be more common in the tropics than in temperate areas, where typically only males sing. Yet the role of phylogeny in this apparent relationship between female song and latitude has never been examined. Here, we reconstruct evolutionary changes in female song and breeding latitude in the New World blackbirds (Icteridae), a family with both temperate and tropical representatives. We provide strong evidence that members of this group have moved repeatedly from tropical to temperate breeding ranges and, furthermore, that these range shifts were associated with losses of female song more often than expected by chance. This historical perspective suggests that male-biased song production in many temperate species is the result not of sexual selection for complex song in males but of selection against such songs in females. Our results provide new insights into the differences we see today between tropical and temperate songbirds, and suggest that the role of sexual selection in the evolution of bird song might not be as simple as we think.     

Phylogenetic relationships and divergence dates of softshell turtles (Testudines: Trionychidae) inferred from complete mitochondrial genomes

The softshell turtles (Trionychidae) are one of the most widely distributed reptile groups in the world, and fossils have been found on all continents except Antarctica. The phylogenetic relationships among members of this group have been previously studied; however, disagreements regarding its taxonomy, its phylogeography and divergence times are still poorly understood as well. Here, we present a comprehensive mitogenomic study of softshell turtles. We sequenced the complete mitochondrial genomes of 10 softshell turtles, in addition to the GenBank sequence of Dogania subplana, Lissemys punctata, Trionyx triunguis, which cover all extant genera within Trionychidae except for Cyclanorbis and Cycloderma. These data were combined with other mitogenomes of turtles for phylogenetic analyses. Divergence time calibration and ancestral reconstruction were calculated using BEAST and RASP software, respectively. Our phylogenetic analyses indicate that Trionychidae is the sister taxon of Carettochelyidae, and support the monophyly of Trionychinae and Cyclanorbinae, which is consistent with morphological data and molecular analysis. Our phylogenetic analyses have established a sister taxon relationship between the Asian Rafetus and the Asian Palea + Pelodiscus + Dogania + Nilssonia + Amyda, whereas a previous study grouped the Asian Rafetus with the American Apalone. The results of divergence time estimates and area ancestral reconstruction show that extant Trionychidae originated in Asia at around 108 million years ago (MA), and radiations mainly occurred during two warm periods, namely Late Cretaceous–Early Eocene and Oligocene. By combining the estimated divergence time and the reconstructed ancestral area of softshell turtles, we determined that the dispersal of softshell turtles out of Asia may have taken three routes. Furthermore, the times of dispersal seem to be in agreement with the time of the India–Asia collision and opening of the Bering Strait, which provide evidence for the accuracy of our estimation of divergence time. Overall, the mitogenomes of this group were used to explore the origin and dispersal route of Trionychidae and have provided new insights on the evolution of this group.     

Molecular Mechanisms of Translation Initiation in Mammals Studied by in vitroReconstruction of Initiation Complexes

Papers on the mechanisms of translation initiation in mammals studied by reconstruction of initiation complexes from individual components are reviewed. The author points to the constraints of this approach and to the pitfalls ignoring which one might come to erroneous conclusions and even artifacts. In addition, some methods employed in the field as well as some technical problems are discussed in the paper, together with the means of obviating them. The review could be a guidebook for newcomers into this quite labor-consuming field.     

Pollen productivity estimates of key European plant taxa for quantitative reconstruction of past vegetation: a review

Information on the spatial distribution of past vegetation on local, regional and global scales is increasingly used within climate modelling, nature conservancy and archaeology. It is possible to obtain such information from fossil pollen records in lakes and bogs using the landscape reconstruction algorithm (LRA) and its two models, REVEALS and LOVE. These models assume that reliable pollen productivity estimates (PPEs) are available for the plant taxa involved in the quantitative reconstructions of past vegetation, and that PPEs are constant through time. This paper presents and discusses the PPEs for 15 tree and 18 herb taxa obtained in nine study areas of Europe. Observed differences in PPEs between regions may be explained by methodological issues and environmental variables, of which climate and related factors such as reproduction strategies and growth forms appear to be the most important. An evaluation of the PPEs at hand so far suggests that they can be used in modelling applications and quantitative reconstructions of past vegetation, provided that consideration of past environmental variability within the region is used to inform selection of PPEs, and bearing in mind that PPEs might have changed through time as a response to climate change. Application of a range of possible PPEs will allow a better evaluation of the results.     

昆虫嗅觉神经的计算机三维重建

基于激光扫描共聚焦显微镜平台的计算机三维重建在昆虫嗅觉神经研究中发挥了重要作用。对经荧光标记的神经组织采集系列光学切片并进行三维重建,在双翅目、鳞翅目、膜翅目、蜚蠊目昆虫中均有进展。触角叶是昆虫的初级嗅觉中心,触角叶的解剖学图谱是识别不同种和雌雄虫间嗅球体特定功能的先决条件。了解构成嗅觉传输途径的主要神经元的形态和空间关系是理解气味信息在中枢神经系统编码的基础。三维重建昆虫的嗅觉神经,对于探讨昆虫嗅觉在其寄主选择、觅食以及寻找配偶等行为中的作用具有非常重要的意义。     

Correlation of surface sediment diatoms with the present lake water pH in 28 Algoma lakes,Ontario, Canada

The surface sediment diatom analysis of 28 Algoma lakes (pH 4.40–8.13) indicates that even though each lake has a widely different aquatic environment and characteristic diatom assemblage, a definite relationship exists between the lake water pH and their diatom assemblages. In the acidic lakes acidobiontic and acidophilous diatom species predominate whereas in circumneutral and alkaline lakes circumneutral and alkaliphilous diatoms were most common. Cluster analysis of the pH indicator diatom assemblages grouped the study lakes into three distinct cluster groups. These groups also closely corresponded to lake water pH. On the basis of published ecological information as well as their presence in our study lakes, the pH indicator status of a number of diatom taxa have been discussed. A detailed listing of the diatom taxa identified and their pH indicator status is provided in order to facilitate their use in future diatom-inferred pH studies.     

Sex differences in leg dexterity are not present in elite athletes

We studied whether the time-varying forces that control unstable foot–ground interactions provide insight into the neural control of dynamic leg function. Twenty elite (10 F, 26.4 ± 3.5 yrs) and 20 recreational (10 F, 24.8 ± 2.4 yrs) athletes used an isolated leg to maximally compress a slender spring designed to buckle at low forces while seated. The foot forces during the compression at the edge of instability quantify the maximal sensorimotor ability to control dynamic foot–ground interactions. Using the nonlinear analysis technique of attractor reconstruction, we characterized the spatial (interquartile range IQR) and geometric (trajectory length TL, volume V, and sum of edge lengths SE) features of the dynamical behavior of those force time series. ANOVA confirmed the already published effect of sex, and a new effect of athletic ability, respectively, in TL (p = 0.014 and p < 0.001), IQR (p = 0.008 and p < 0.001), V (p = 0.034 and p = 0.002), and SE (p = 0.033 and p < 0.001). Further analysis revealed that, for recreational athletes, females exhibited weaker corrective actions and greater stochasticity than males as per their greater mean values of TL (p = 0.003), IQR (p = 0.018), V (p = 0.017), and SE (p = 0.025). Importantly, sex differences disappeared in elite athletes. These results provide an empirical link between sex, athletic ability, and nonlinear dynamical control. This is a first step in understanding the sensorimotor mechanisms for control of unstable foot–ground interactions. Given that females suffer a greater incidence of non-contact knee ligament injuries, these non-invasive and practical metrics of leg dexterity may be both indicators of athletic ability, and predictors of risk of injury.     

Phylogeny of the superfamily Gelechioidea (Lepidoptera: Obtectomera), with an exploratory application on geometric morphometrics

The superfamily Gelechioidea (Lepidoptera: Obtectomera) has a high species diversity. It consists of more than 18,400 described species and has a global distribution. Among it, large numbers of species were reported to be economically important to people's production and life. However, relationships among families or subfamilies in Gelechioidea have been exceptionally difficult to resolve using morphology or single gene genealogies. Multiple gene genealogies had been used in the molecular phylogenetic studies on Gelechioidea during the past years, but their phylogenetic relationships remain to be controversial mainly due to their limited taxa sampling relative to such high species diversity. In this paper, 89 ingroup species representing 55 genera are sequenced and added to the data downloaded from GenBank, and six species representing four closely related superfamilies are chosen as outgroup. The molecular phylogeny of Gelechioidea is reconstructed based on the concatenated data set composed of one mitochondrial marker (COI) and seven nuclear markers (CAD, EF-1ɑ, GAPDH, IDH, MDH, RpS5, wingless). The phylogenetic results, taking into consideration of the comparative morphological study, show that the clade of Gelechioidea is strongly supported and separated from other superfamilies, which further proves its monophyly. Five families are newly defined: Autostichidae sensu nov., Depressariidae sensu nov., Peleopodidae sensu nov., Ashinagidae sensu nov. and Epimarptidae sensu nov. Meanwhile, a monophyletic “SSABM” clade considered to be closely related is proposed for the first time, consisting of Stathmopodidae, Scythrididae, Ashinagidae, Blastobasidae and Momphidae. Moreover, geometric morphometric analyses using merged landmark data set from fore and hind wings of 118 representative species are conducted. The phenetic tree shows that the monophyly and phylogenetic relationships correspond with the results of molecular phylogeny largely, which well proves its importance and potential application in both phylogenetic reconstruction and species identification.