Phenotypic plasticity can allow organisms to respond to environmental changes by producing better matching phenotypes without any genetic change. Because of this, plasticity is predicted to be a major mechanism by which a population can survive the initial stage of colonizing a novel environment. We tested this prediction by challenging wild Drosophila melanogaster with increasingly extreme larval environments and then examining expression of alcohol dehydrogenase (ADH) and its relationship to larval survival in the first generation of encountering a novel environment. We found that most families responded in the adaptive direction of increased ADH activity in higher alcohol environments and families with higher plasticity were also more likely to survive in the highest alcohol environment. Thus, plasticity of ADH activity was positively selected in the most extreme environment and was a key trait influencing fitness. Furthermore, there was significant heritability of ADH plasticity that can allow plasticity to evolve in subsequent generations after initial colonization. The adaptive value of plasticity, however, was only evident in the most extreme environment and had little impact on fitness in less extreme environments. The results provide one of the first direct tests of the adaptive role of phenotypic plasticity in colonizing a novel environment.

Epidermolysis bullosa (EB) represents a group of inherited blistering skin diseases, some forms of which are associated with considerable morbidity and increased mortality. Notably, in recessive dystrophic EB there can be extensive muco-cutaneous fragility and disease complications such as scars, contractures, anemia, malnutrition, and malignancy. Currently, there is no effective therapy or cure for EB. Over the last decade, however, a number of important advances have been made that are bringing new treatments closer to the clinic, including gene therapy, protein replacement therapy, cell therapies [allogeneic fibroblasts, mesenchymal stromal cells (MSCs), bone marrow stem cell transplantation, culturing/grafting revertant mosaic keratinocytes], gene editing/engineering, and clinical application of inducible pluripotent stem cells. Although a cure for EB still remains elusive, recent data on animal models and initial human clinical trials have raised the expectations of patients, clinicians, and researchers that disease modification and improved quality of life are feasible goals. Furthermore, the lessons learned in treating EB are likely to have significant implications for improving the management of other genetic diseases.

Mutualisms, or reciprocally beneficial interspecific interactions, constitute the foundation of many ecological communities and agricultural systems. Mutualisms come in different forms, from pairwise interactions to extremely diverse communities, and they are continually challenged with exploitation by nonmutualistic community members (exploiters). Thus, understanding how mutualisms persist remains an essential question in ecology. Theory suggests that high species richness and functional redundancy could promote mutualism persistence in complex mutualistic communities. Using a yeast system (Saccharomyces cerevisiae), we experimentally show that communities with the greatest mutualist richness and functional redundancy are nearly two times more likely to survive exploitation than are simple communities. Persistence increased because diverse communities were better able to mitigate the negative effects of competition with exploiters. Thus, large mutualistic networks may be inherently buffered from exploitation.

Wang and Althoff (2019) explored the capacity of Drosophila melanogaster to exhibit adaptive plasticity in a novel environment. In a full‐sib, half‐sib design, they scored the activity of the enzyme alcohol dehydrogenase (ADH) and plastic responses, measured as changes in ADH activity across ethanol concentrations in the range of 0–10% (natural variation) and 16% (the novel environment). ADH activity increased with alcohol concentration, and there was a positive association between larval viability and ADH activity in the novel environment. They also reported that families exhibiting greater plasticity had higher larval survival in the novel environment, concluding that ADH plasticity is adaptive. However, the four authors now concur that, since the study estimated plasticity from phenotypic differences across environments using full‐sib families, it is not possible to disentangle the contributions of allele frequency changes at the Adh locus from regulatory control at loci known to influence ADH activity. Selective changes in allele frequencies may thus conflate estimates of plasticity; any type of “plasticity” (adaptive, neutral, or maladaptive) could be inferred depending on allele frequencies. The problem of scoring sib‐groups after selection should be considered in any plasticity study that cannot use replicated genotypes. Researchers should monitor changes in allele frequencies as one mechanism to deal with this issue.

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