Hormonally mediated maternal effects, individual strategy and global change

Abstract

A challenge to ecologists and evolutionary biologists is predicting organismal responses to the anticipated changes to global ecosystems through climate change. Most evidence suggests that short-term global change may involve increasing occurrences of extreme events, therefore the immediate response of individuals will be determined by physiological capacities and life-history adaptations to cope with extreme environmental conditions. Here, we consider the role of hormones and maternal effects in determining the persistence of species in altered environments. Hormones, specifically steroids, are critical for patterning the behaviour and morphology of parents and their offspring. Hence, steroids have a pervasive influence on multiple aspects of the offspring phenotype over its lifespan. Stress hormones, e.g. glucocorticoids, modulate and perturb phenotypes both early in development and later into adulthood. Females exposed to abiotic stressors during reproduction may alter the phenotypes by manipulation of hormones to the embryos. Thus, hormone-mediated maternal effects, which generate phenotypic plasticity, may be one avenue for coping with global change. Variation in exposure to hormones during development influences both the propensity to disperse, which alters metapopulation dynamics, and population dynamics, by affecting either recruitment to the population or subsequent life-history characteristics of the offspring. We suggest that hormones may be an informative index to the potential for populations to adapt to changing environments.

Determining environmental causes of biological effects: the need for a mechanistic physiological dimension in conservation biology

“…A shift in the environment that causes a mismatch between environmental conditions and optimal temperatures for individual physiological performance can therefore cause population declines and extinctions if performance optima are fixed within populations. Hence, there is a need to understand individual responses to changing environments and then translate these to populations, species and communities [8,11,12].…”

“…We argue here that in many if not most cases, the physiology of individuals provides this link between cause and effect, and can thereby explain ecological patterns. Physiological capacities and responses act as a filter between environmental change and ecological performance of individuals and, hence, populations and species [11,12] (figure 1).…”

Extinction or Survival? Behavioral Flexibility in Response to Environmental Change in the African Striped Mouse Rhabdomys

“…At the individual level, switching between social tactics is mediated by the endocrine system [53]. Hormones can alter physiological and behavioral responses [108], enabling individuals to switch between behavioral phenotypes. These patterns of hormonal secretion are sensitive to changes in environmental conditions.…”

“…Philopatric males that leave their group increase their testosterone levels while at the same time decreasing their corticosterone levels, and philopatrics and roamers males that become paternal territorial breeders additionally increase their prolactin levels [110]. However, patterns of hormonal secretion can also be influenced during the early neonatal environment by the mother (i.e., maternal effects [108]), which influence behavior. In R. pumilio, solitary breeding females provide 1½ times more care to their young than paired females, resulting in their sons showing higher levels of paternal care as adults [111].…”

Coping with Change: A Closer Look at the Underlying Attributes of Change and the Individual Response to Unstable Environments

“…Often, hormonal or nutritional effects get passed down passively to the next generation based on the mother's state during gestation [100]. As a result, effects are not by default adaptive, and can even be counter-adaptive when environments change strongly within the individual's lifespan [101,102].…”