Is the speed of adjusting to environmental change condition dependent? An experiment with house mice (Mus musculus)

Abstract

Environmental conditions change constantly either by anthropogenic perturbation or naturally across space and time. Often, a change in behaviour is the first response to changing conditions. Behavioural flexibility can potentially improve an organism’s chances to survive and reproduce. Currently, we lack an understanding on the time-scale such behavioural adjustments need, how they actually affect reproduction and survival and whether behavioural adjustments are sufficient in keeping up with changing conditions. We used house mice (Mus musculus) to test whether personality and life-history traits can adjust to an experimentally induced food-switch flexibly in adulthood or by intergenerational plasticity, i.e., adjustments only becoming visible in the offspring generation. Mice lived in six experimental populations of semi-natural environments either on high or standard quality food for four generations. We showed previously that high-quality food induced better condition and a less risk-prone personality. Here, we tested whether the speed and/ or magnitude of adjustment shows condition-dependency and whether adjustments incur fitness effects. Life-history but not personality traits reacted flexibly to a food-switch, primarily by a direct reduction of reproduction and slowed-down growth. Offspring whose parents received a food-switch developed a more active stress-coping personality and gained weight at a slower rate compared to their respective controls. Furthermore, the modulation of most traits was condition-dependent, with animals previously fed with high-quality food showing stronger responses. Our study highlights that life-history and personality traits adjust at different speed towards environmental change, thus, highlighting the importance of the environment and the mode of response for evolutionary models.

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

“…Contrary to previous findings in mice from semi-natural enclosures (Lopez-Hervas et al, 2024;Prabh et al, 2023), we found that cage-housed mice on a high-quality diet covered more distance in the Open Field compared to the standard-quality food group (Figure 1). This result implies that high-quality food promotes an active stress-coping strategy in caged-house mice.…”

“…Mice might employ these strategies as an insurance against variation in food quality (Mathot et al, 2012). Mice previously receiving high-quality food have reproductive value to lose and might protect these 'assets' by reducing risky exposure to threats and predators (Clark, 1994;Lopez-Hervas et al, 2024;McElreath et al, 2007;Wolf et al, 2007).…”

“…Here, we highlight two recent studies in wild house mice (Mus musculus domesticus) living in semi-natural conditions (Lopez-Hervas et al, 2024;Prabh et al, 2023). Both studies explored how changes in nutritional quality shape stress-coping behaviors and life-history traits.…”

“…In a subsequent study, Lopez-Hervas et al (2024) contrasted trans-and within generational effects of changes in nutritional conditions in the same population of mice. The authors found that adult mice were able to flexibly adjust life-history traits (reproduction, weight, and growth rates but not survival) to changes in food quality.…”

“…Ultimately, we attempted to answer the following research questions: First, how does stress coping change as a function of food quality across ontogeny; second, when during ontogeny is stress-coping in mice most sensitive towards a food switch? We derive hypotheses for these research questions based on previous studies (Lopez-Hervas et al, 2024;Prabh et al, 2023).…”