Excerpt 1): “…stress is “a psychological and physical reaction to external stimuli…”
My comment: Identification of the start signal associated with stress does not link it to mutations and natural selection in the context of the evolution of biodiversity. Instead, identification of the start signal links it from ecological variation to ecological adaptations via conserved molecular mechanisms in species from microbes to man.
“The newer and often redefined terms for pheromones limit the use of what is now known about their epigenetic effects, which are also associated with social stress on adaptively evolved socio-cognitive niche construction (Flinn, Nepomnaschy, Muehlenbein, & Ponzi, 2011; O’Connell & Hofmann, 2011, 2012; Whiten & Erdal, 2012). For example, social stress (see for review McEwen, 2012, 2013) associated with the absence of pheromones (Niwa et al., 2013) or with their presence and aggression (Barik et al., 2013) is as likely as nutrient-dependent stress associated with food acquisition to alter hormones and behavior during development. That is because the epigenetic effects of nutrient stress associated with food odors and the epigenetic effects of social stress associated with pheromones occur via the GnRH-controlled pathway, which includes both HPG axis and HPA axis regulation.” Kohl (2013)