A climate for contemporary evolution

A new study of divergence in freshwater fish provides strong evidence of rapid, temperature-mediated adaptation. This study is particularly important in the ongoing debate over the extent and significance of evolutionary response to climate change because divergence has occurred in relatively few generations in spite of ongoing gene flow and in the aftermath of a significant genetic bottleneck, factors that have previously been considered obstacles to evolution. Climate change may thus be more likely to foster contemporary evolutionary responses than has been anticipated, and I argue here for the importance of investigating their possible occurrence.     

Postnatal changes of some enzymatic activities of energy supplying metabolism in the cortex, inner and outer medulla of the rat kidney

1. In rat kidney cortex, outer and inner medulla the development of activities of seven enzymes was investigated during postnatal ontogeny (10, 20, 30, 60 and 90 days of age). The enzymes were selected in such a manner, as to characterize most of the main metabolic pathways of energy supplying metabolism: hexokinase (glucose phosphorylation, HK), glycerol-3-phosphate dehydrogenase (glycerolphosphate metabolism or shunt, GPDH), triose phosphate dehydrogenase (glycolytic carbohydrate breakdown, TPDH), lactate dehydrogenase (lactate metabolism, LDH), citrate synthase (tricarboxylic acid cycle, aerobic metabolism, CS), malate NAD dehydrogenase (tricarboxylic acid cycle, intra-extra mitochondrial hydrogen transport, MDH) and 3-hydroxyacyl-CoA-dehydrogenase (fatty acid catabolism, HOADH). 2. The renal cortex already differs metabolically from the medullar structures on the 10th day of life. It displays a high activity of aerobic breakdown of both fatty acids and carbohydrates. Its metabolic capacity further increases up to the 30th day of life. 3. The outer medullar structure is not grossly different from the inner medulla on the 10th day of life. Further it differentiates into a highly aerobic tissue mainly able to utilize carbohydrates. It can, however, to some extent, also utilize fatty acids aerobically and produce lactate from carbohydrates anaerobically. 4. The inner medullar structure is best equipped to utilize carbohydrates by anaerobic glycolysis, forming lactate. This feature is already pronounced on the 10th day of life, its capacity increases to some extent during postnatal development, being highest between the 10th and the 60th day of life.     

Plant phylogeny drives arboreal caterpillar assemblages across the Holarctic

1. Assemblages of insect herbivores are structured by plant traits such as nutrient content, secondary metabolites, physical traits, and phenology. Many of these traits are phylogenetically conserved, implying a decrease in trait similarity with increasing phylogenetic distance of the host plant taxa. Thus, a metric of phylogenetic distances and relationships can be considered a proxy for phylogenetically conserved plant traits and used to predict variation in herbivorous insect assemblages among co‐occurring plant species.
2. Using a Holarctic dataset of exposed‐feeding and shelter‐building caterpillars, we aimed at showing how phylogenetic relationships among host plants explain compositional changes and characteristics of herbivore assemblages.
3. Our plant–caterpillar network data derived from plot‐based samplings at three different continents included >28,000 individual caterpillar–plant interactions. We tested whether increasing phylogenetic distance of the host plants leads to a decrease in caterpillar assemblage overlap. We further investigated to what degree phylogenetic isolation of a host tree species within the local community explains abundance, density, richness, and mean specialization of its associated caterpillar assemblage.
4. The overlap of caterpillar assemblages decreased with increasing phylogenetic distance among the host tree species. Phylogenetic isolation of a host plant within the local plant community was correlated with lower richness and mean specialization of the associated caterpillar assemblages. Phylogenetic isolation had no effect on caterpillar abundance or density. The effects of plant phylogeny were consistent across exposed‐feeding and shelter‐building caterpillars.
5. Our study reveals that distance metrics obtained from host plant phylogeny are useful predictors to explain compositional turnover among hosts and host‐specific variations in richness and mean specialization of associated insect herbivore assemblages in temperate broadleaf forests. As phylogenetic information of plant communities is becoming increasingly available, further large‐scale studies are needed to investigate to what degree plant phylogeny structures herbivore assemblages in other biomes and ecosystems.