Plant Species Loss Affects Life-History Traits of Aphids and Their Parasitoids

The consequences of plant species loss are rarely assessed in a multi-trophic context and especially effects on life-history traits of organisms at higher trophic levels have remained largely unstudied. We used a grassland biodiversity experiment and measured the effects of two components of plant diversity, plant species richness and the presence of nitrogen-fixing legumes, on several life-history traits of naturally colonizing aphids and their primary and secondary parasitoids in the field. We found that, irrespective of aphid species identity, the proportion of winged aphid morphs decreased with increasing plant species richness, which was correlated with decreasing host plant biomass. Similarly, emergence proportions of parasitoids decreased with increasing plant species richness. Both, emergence proportions and proportions of female parasitoids were lower in plots with legumes, where host plants had increased nitrogen concentrations. This effect of legume presence could indicate that aphids were better defended against parasitoids in high-nitrogen environments. Body mass of emerged individuals of the two most abundant primary parasitoid species was, however, higher in plots with legumes, suggesting that once parasitoids could overcome aphid defenses, they could profit from larger or more nutritious hosts. Our study demonstrates that cascading effects of plant species loss on higher trophic levels such as aphids, parasitoids and secondary parasitoids begin with changed life-history traits of these insects. Thus, life-history traits of organisms at higher trophic levels may be useful indicators of bottom-up effects of plant diversity on the biodiversity of consumers

Complete Ichthyornis skull illuminates mosaic assembly of the avian head

The skull of living birds is greatly modified from the condition found in their dinosaurian antecedents. Bird skulls have an enlarged, toothless premaxillary beak and an intricate kinetic system that includes a mobile palate and jaw suspensorium. The expanded avian neurocranium protects an enlarged brain and is flanked by reduced jaw adductor muscles. However, the order of appearance of these features and the nature of their earliest manifestations remain unknown. The Late Cretaceous toothed bird Ichthyornis dispar sits in a pivotal phylogenetic position outside living groups: it is close to the extant avian radiation but retains numerous ancestral characters 1-3. Although its evolutionary importance continues to be affirmed 3-8, no substantial new cranial material of I. dispar has been described beyond incomplete remains recovered in the 1870s. Jurassic and Cretaceous Lagerstatten have yielded important avialan fossils, but their skulls are typically crushed and distorted 9. Here we report four three-dimensionally preserved specimens of I. dispar- including an unusually complete skull-as well as two previously overlooked elements from the Yale Peabody Museum holotype, YPM 1450. We used these specimens to generate a nearly complete three-dimensional reconstruction of the I. dispar skull using highresolution computed tomography. Our study reveals that I. dispar had a transitional beak-small, lacking a palatal shelf and restricted to the tips of the jaws-coupled with a kinetic system similar to that of living birds. The feeding apparatus of extant birds therefore evolved earlier than previously thought and its components were functionally and developmentally coordinated. The brain was relatively modern, but the temporal region was unexpectedly dinosaurian: it retained a large adductor chamber bounded dorsally by substantial bony remnants of the ancestral reptilian upper temporal fenestra. This combination of features documents that important attributes of the avian brain and palate evolved before the reduction of jaw musculature and the full transformation of the beak. </p

The socio-emotional basis of human interaction and communication: How we construct our social world

This publication is with permission of the rights owner freely accessible due to an alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.A review of dimensional research about (the perception of) feelings, non-verbal and verbal communication, behavior and personality reveals in each domain three very similar dimensions. They originated from diverse research areas, often received different names and are conceptually not identical. Yet, the first dimension seems to share in all five areas a general positive versus negative evaluation (e.g. happiness–disgust or friendliness–hostility), the second a strong versus weak characterization (e.g. anger–fear or dominance–submission) and the third dimension an active versus passive impression (e.g. ecstasy–boredom or high–low arousability). These three dimensions are likely to function as fundamental dimensions of interaction and communication as perceived and enacted by humans of all (investigated) cultures. They are interpreted as a universal socio-emotional space that corresponds to an evolutionary need for coordination between individuals. They are implied in the logic of game, exchange or interdependence theory, and manifest themselves in the cultural meanings predicted by affect control theory. The presented overview and reconstruction combines the largely fragmented views of several diverse research domains into a perspective that fosters interdisciplinary understanding and integrative theory-building about human sociality within and between the social sciences with extensions into the natural sciences and humanities.Un passage en revue de la recherche dimensionnelle sur les sentiments (et leur perception), la communication verbale et non-verbale, le comportement et la personnalité, met en évidence trois dimensions très similaires pour chacun de ces domaines. Elles proviennent de différents domaines de recherche, ont souvent reçu des dénominations différentes et ne sont pas identiques conceptuellement. Cependant, la première dimension semble partager dans ces cinq domaines une évaluation positive versus négative (e.g., joie–dégoût ou amitié–hostilité), la deuxième une caractérisation fort versus faible (e.g. colère–peur ou dominance–soumission) et la troisième une impression actif versus passif (e.g. extase–ennui ou stimulation haute–basse). Ces trois dimensions fonctionnent vraisemblablement comme des dimensions fondamentales d’interaction et de communication perçues et émises par les humains de toutes les cultures (étudiées). Elles sont interprétées comme un espace socio-émotionnel universel qui correspond à un besoin au cours de l’évolution de coordination entre les individus. Elles sont impliquées dans la logique du jeu, de l’échange et la théorie de l’interdépendance, et se manifestent dans les significations culturelles prédites par la théorie du contrôle des affects. La présente étude combine les visions largement fragmentées de nombreux et divers domaines de recherche en une perspective qui veut promouvoir une compréhension interdisciplinaire et construire une théorie intégrative sur la socialité humaine dans et entre les sciences sociales avec des ramifications vers les sciences naturelles et les humanités.Peer Reviewe

Crystal structures explain functional properties of two E. coli porins

Porins form aqueous channels that aid the diffusion of small hydrophilic molecules across the outer membrane of Gram-negative bacteria. The crystal structures of matrix porin and phosphoporin both reveal trimers of identical subunits, each subunit consisting of a 16-stranded anti-parallel beta-barrel containing a pore. A long loop inside the barrel contributes to a constriction of the channel where the charge distribution affects ion selectivity. The structures explain at the molecular level functional characteristics and their alterations by known mutations