There was an error published in J. Exp. Biol. 209,[3141][3142][3143][3144][3145][3146][3147][3148][3149][3150][3151][3152][3153][3154] In paragraph 4 of the Respirometry section of the Materials and methods, the authors stated: Therefore, energy consumption was estimated using a constant equivalent of 20·kJ·l -1 O 2 and then converted to watts using 1·W=0

.-In the calidrine sandpiper red knot (Calidris canutus), the weeks preceding takeoff for long-distance migration are characterized by a rapid increase in body mass, largely made up of fat but also including a significant proportion of lean tissue. Before takeoff, the pectoral muscles are known to hypertrophy in preparation for endurance flight without any specific training. Because birds facing cold environments counterbalance heat loss through shivering thermogenesis, and since pectoral muscles represent a large proportion of avian body mass, we asked the question whether muscle hypertrophy in preparation for long-distance endurance flight would induce improvements in thermogenic capacity. We acclimated red knots to different controlled thermal environments: 26°C, 5°C, and variable conditions tracking outdoor temperatures. We then studied within-individual variations in body mass, pectoral muscle size (measured by ultrasound), and metabolic parameters [basal metabolic rate (BMR) and summit metabolic rate (M sum)] throughout a 3-mo period enclosing the migratory gain and loss of mass. The gain in body mass during the fattening period was associated with increases in pectoral muscle thickness and thermogenic capacity independent of thermal acclimation. Regardless of their thermal treatment, birds showing the largest increases in body mass also exhibited the largest increases in M sum. We conclude that migratory fattening is accompanied by thermoregulatory side effects. The gain of body mass and muscle hypertrophy improve thermogenic capacity independent of thermal acclimation in this species. Whether this represents an ecological advantage depends on the ambient temperature at the time of fattening. muscle mass; summit metabolic rate; basal metabolic rate; thermogenic capacity; phenotypic flexibility LONG-DISTANCE MIGRATION IN birds is an energy-demanding phenomenon that leads to remarkable physiological adjustments that are among the best-known examples of phenotypic flexibility in higher vertebrates (52,59). In birds preparing for long-distance flights, the period of migratory fattening often involves a reorganization of specific physiological systems, including metabolic changes ranging from the level of the cell (24,42,43,44,46,65,66) to that of the whole animal (6,33,39,79). In the weeks preceding takeoff, as well as during a refueling stopover, birds have to maximize energy input to accumulate the fat stores necessary to fuel their nonstop flight. To do so, they enter a hyperphagic phase with extreme energy assimilation rates (34,38,60

Recombination is a fundamental process with significant impacts on genome evolution. Predicted consequences of the loss of recombination include a reduced effectiveness of selection, changes in the amount of neutral polymorphisms segregating in populations, and an arrest of GC-biased gene conversion. Although these consequences are empirically well documented for nonrecombining genome portions, it remains largely unknown if they extend to the whole genome scale in asexual organisms. We identify the consequences of asexuality using de novo transcriptomes of five independently derived, obligately asexual lineages of stick insects, and their sexual sister-species. We find strong evidence for higher rates of deleterious mutation accumulation, lower levels of segregating polymorphisms and arrested GC-biased gene conversion in asexuals as compared with sexuals. Taken together, our study conclusively shows that predicted consequences of genome evolution under asexuality can indeed be found in natural populations.

There was an error published in J. Exp. Biol. 209,[3141][3142][3143][3144][3145][3146][3147][3148][3149][3150][3151][3152][3153][3154] In paragraph 4 of the Respirometry section of the Materials and methods, the authors stated: Therefore, energy consumption was estimated using a constant equivalent of 20·kJ·l -1 O 2 and then converted to watts using 1·W=0

In this study, we characterize changes in the genome during a swift evolutionary adaptation, by combining experimental selection with high-throughput sequencing. We imposed strong experimental selection on an ecologically relevant trait, parasitoid resistance in Drosophila melanogaster against Asobara tabida. Replicated selection lines rapidly evolved towards enhanced immunity. Larval survival after parasitization increased twofold after just five generations of selection. Whole-genome sequencing revealed that the fast and strong selection response in innate immunity produced multiple, highly localized genomic changes. We identified narrow genomic regions carrying a significant signature of selection, which were present across all chromosomes and covered in total less than 5% of the whole D. melanogaster genome. We identified segregating sites with highly significant changes in frequency between control and selection lines that fell within these narrow 'selected regions'. These segregating sites were associated with 42 genes that constitute possible targets of selection. A region on chromosome 2R was highly enriched in significant segregating sites and may be of major effect on parasitoid defence. The high genetic variability and small linkage blocks in our base population are likely responsible for allowing this complex trait to evolve without causing widespread erosive effects in the genome, even under such a fast and strong selective regime.