Source-sink migration of natural enemies drives maladaptation of victim populations in sink habitats.

Natural enemies are critical drivers of species biogeography, and they may often limit the evolutionary adaptation and persistence of victim populations in sink habitats. Source-sink migration is also a major determinant of adaptation in sink habitats. Here, we specifically suggest that source-sink migration of enemies reduces evolutionary adaptation of victim populations in sink habitats.

Overcoming the growth-infectivity trade-off in a bacteriophage slows bacterial resistance evolution.

The use of lytic bacteriophages for treating harmful bacteria (phage therapy) is faced with the challenge of bacterial resistance evolution. Phage strains with certain traits, for example, rapid growth and relatively broad infectivity ranges, may enjoy an advantage in slowing bacterial resistance evolution. Here, we show the possibility for laboratory selection programs ("evolutionary training") to yield phage genotypes with both high growth rate and broad infectivity, traits between which a trade-off has been assumed.

Interspecific Niche Competition Increases Morphological Diversity in Multi-Species Microbial Communities.

Intraspecific competition for limited niches has been recognized as a driving force for adaptive radiation, but results for the role of interspecific competition have been mixed. Here, we report the adaptive diversification of the model bacteria in the presence of different numbers and combinations of four competing bacterial species. Increasing the diversity of competitive community increased the morphological diversity of focal species, which is caused by impeding the domination of a single morphotype.

Consequences of mutation accumulation for growth performance are more likely to be resource-dependent at higher temperatures.

Background: Mutation accumulation (MA) has profound ecological and evolutionary consequences. One example is that accumulation of conditionally neutral mutations leads to fitness trade-offs among heterogenous habitats which cause population divergence. Here we suggest that temperature, which controls the rates of all biochemical and biophysical processes, should play a crucial role for determining mutational effects.

Warmer temperatures enhance beneficial mutation effects.

Temperature determines the rates of all biochemical and biophysical processes, and is also believed to be a key driver of macroevolutionary patterns. It is suggested that physiological constraints at low temperatures may diminish the fitness advantages of otherwise beneficial mutations; by contrast, relatively high, benign, temperatures allow beneficial mutations to efficiently show their phenotypic effects. To experimentally test this "mutational effects" mechanism, we examined the fitness effects of mutations across a temperature gradient using bacterial genotypes from the early stage of a mutation accumulation experiment with Escherichia coli.