Biology subjects

Walasek, N.

Publications and source records attributed to Walasek, N..

2 recordsLinked to original sources

bioRxiv2024

The evolution of reversible plasticity in stable environments

Phenotypic plasticity - the capacity of a genotype to develop into different phenotypes depending on environmental inputs - is widespread in nature. Although the construction of phenotypes is often the focus of research, many animals are also able to deconstruct phenotypic adjustments. Organisms routinely use such reversible plasticity to adjust to changes in their social or physical environment. For example, various invertebrates are able to deconstruct defensive morphologies previously built to defend against predators. Theory that explores the selection pressures favoring reversibility is scarce. Existing theory has almost exclusively focused on traits that develop instantaneously rather than incrementally, as is common with many morphological traits. Here, we present a model of the evolution of reversible plasticity when organisms develop incrementally. In our model, organisms repeatedly sample cues to infer the environmental state - which varies between generations but is stable across the lifetime - and incrementally adjust their phenotype to match their environment. Organisms have the possibility to deconstruct phenotypic adjustments. We assume two different modes of phenotypic deconstruction: Organisms can either deconstruct phenotypic adjustments incrementally or completely deconstruct all phenotypic adjustments in one time period. We highlight two results. First, while plasticity in construction is typically highest early in ontogeny, the highest levels of plasticity in deconstruction typically occur in mid-ontogeny. Second, contrasting previous models, we find that reversibility evolves frequently in stable environments and in species with shorter lifespans. Our model thus shows that reversibility does not require environmental change. Rather, reversibility may be favored when organisms are uncertain about the environmental state because the environment can change across generations. Our work illustrates the capacity for reversibility in species who experience environmental changes for the first time in their lives.

evolutionary biology↗

bioRxiv2024

Personality development in wild house mice: Evidence for a nutrition-dependent sensitive period early in life

Changing environmental conditions pose serious challenges to organisms, for example, by disrupting access to food. Across species and traits, animals use phenotypic plasticity to rapidly adjust to such changes. Previous work has demonstrated that wild house mice are able to adjust stress coping to changing food quality within just three generations. However, we do not know when during ontogeny changing conditions induce phenotypic adjustments. We tested experimentally when during ontogeny (as fetus, newborn, weanling, or late adolescent) a food switch between standard and high-quality food shapes personality development (stress coping and stress perception) in cage-housed, wild house mice (Mus musculus domesticus). Personality traits were assessed in the Open Field and the Elevated Plus Maze at different time points during ontogeny (weaning, early adolescence, late adolescence, and adulthood). We observed three key findings. First, as mice grow older they tend to use more passive stress-coping strategies, indicating higher risk aversion. This relationship holds irrespective of food quality. However, mice fed with high-quality food show, on average, more active stress coping compared to mice receiving standard-quality food. Second, the fetal life stage might be a sensitive period for stress coping in response to experiencing decreases in nutritional quality. Third, experiencing an increase in nutritional quality may slow the age-related switch towards a passive stress-coping strategy. Our findings contrast previous work observing passive stress coping in mice living in semi-natural enclosures fed with high-quality food. We propose that the social environment of mice living in cages vs mice living in small groups may explain these differences. Our results highlight the need for experiments across the breadth of development comparing captive and semi-free-living animals. Ultimately, such studies will help us understand the complex relationships between development, nutrition, the (social) environment, and personality.

animal behavior and cognition↗