Developmental plasticity in reptiles: Insights into thermal and maternal effects on chameleon phenotypes

2018 ◽  
Vol 329 (6-7) ◽  
pp. 298-307 ◽  
Author(s):  
Robin M. Andrews
Keyword(s):  
Maternal Effects ◽  
Developmental Plasticity

scholarly journals What kind of maternal effects are selected for in fluctuating environments?

2015 ◽  
Author(s):  
Stephen R Proulx ◽  
Henrique Teotonio
Keyword(s):  
Maternal Effects ◽  
Developmental Plasticity ◽  
Ancestral State ◽  
Bet Hedging ◽  
Alternative Phenotypes ◽  
Fluctuating Environments ◽  
Small Set ◽  
The One ◽  
Maternal Strategy

Adaptation to temporally fluctuating environments can be achieved through direct phenotypic evolution, by phenotypic plasticity (either developmental plasticity or trans-generational plasticity), or by randomizing offspring phenotypes (often called diversifying bet-hedging). Theory has long held that plasticity can evolve when information about the future environment is reliable while bet-hedging can evolve when mixtures of phenotypes have high average fitness (leading to low among generation variance in fitness). To date, no study has studied the evolutionary routes that lead to the evolution of randomized offspring phenotypes on the one hand or deterministic maternal effects on the other. We develop simple, yet general, models of the evolution of maternal effects and are able to directly compare selection for deterministic and randomizing maternal effects and can also incorporate the notion of differential maternal costs of producing offspring with alternative phenotypes. We find that only a small set of parameters allow bet hedging type strategies to outcompete deterministic maternal effects. Not only must there be little or no informative cues available, but also the frequency with which different environments are present must fall within a narrow range. By contrast, when we consider the joint evolution of the maternal strategy and the set of offspring phenotypes we find that deterministic maternal effects can always invade the ancestral state (lacking any form of maternal effect). The long-term ESS may, however, involve some form of offspring randomization, but only if the phenotypes evolve extreme differences in environment-specific fitness. Overall we conclude that deterministic maternal effects are much more likely to evolve than offspring randomization, and offspring randomization will only be maintained if it results in extreme differences in environment-specific fitness.

scholarly journals Non-genetic maternal effects shape individual differences in cortisol phenotypes in wild chimpanzees

2021 ◽  
Author(s):  
Patrick J Tkaczynski ◽  
Fabrizio Mafessoni ◽  
Cedric Girard-Buttoz ◽  
Liran Samuni ◽  
Corinne Y Ackermann ◽  
...  
Keyword(s):  
Individual Differences ◽  
Parental Care ◽  
Maternal Effects ◽  
Developmental Plasticity ◽  
Time Of Day ◽  
Vital Role ◽  
Homeostatic Function ◽  
Cortisol Responses ◽  
Cortisol Levels

Glucocorticoids, such as cortisol, mediate homeostatic processes, allowing individuals to adjust to fluctuating environments. The regulation of circadian cortisol responses, a key homeostatic function, has been shown to be heritable. However, to understand better the role of parental care in shaping physiological functioning in long-lived mammals with protracted parental care, there is a need to disentangle genetic and non-genetic parental contributions to variation in glucocorticoid phenotypes. We used a dataset of 6,123 cortisol measures from urine samples from 170 wild chimpanzees spanning 18 years of data collection. We found consistent inter-individual differences in circadian cortisol phenotypes, with differences most apparent when considering average cortisol levels given the effect of time of day. Maternal effects explained around 10% (2-18%) variation in these average cortisol levels, while variation attributable to genetic factors was not distinguishable from zero. Our results indicate, relative to genetic effects, a qualitatively stronger influence of mothers, whether via epigenetic processes or via behavioral priming for coping with stressors, in shaping cortisol phenotypes in this species. This provides novel insight into the vital role of mothers in the developmental plasticity of long-lived mammals and, more generally, the selective pressures shaping physiological plasticity.

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