Life in varying environments: experimental evidence for delayed effects of juvenile environment on adult life history

Abstract

Summary1. The effects of environment experienced during early development on phenotype as an adult has started to gain vast amounts of interest in various taxa. Some evidence on long-term effects of juvenile environment is available, but replicated experimental studies in wild animals are still lacking. 2. Here we report the first replicated experiment in wild mammals which examines the long-term effects of juvenile and adult environments on individual fitness (reproduction, survival and health). The early development of bank vole (Myodes glareolus) individuals took place in either foodsupplemented or un-supplemented outdoor enclosures. After the summer, adult individuals were reciprocally changed to either a similar or opposite resource environment to overwinter. 3. Adult environment had an overriding effect on reproductive success of females so that females overwintering in food-supplemented enclosures had a higher probability of breeding and advanced the initiation of breeding. However, the characteristics of their litters were determined by juvenile environment: females initially grown in food-supplemented conditions subsequently produced larger litters with bigger pups and a male-biased sex ratio. 4. In males, individuals growing in un-supplemented conditions had the highest survival irrespective of adult environment during winter, whereas in females, neither the juvenile nor adult environments affected their survival significantly. The physiological condition of voles in spring, as determined by haematological parameters, was also differentially affected by juvenile (plasma proteins and male testosterone) and adult (haematocrit) environments. 5. Our results suggest that (i) life-history trajectories of voles are not strictly specialized to a certain environment and (ii) the plastic life-history responses to present conditions can actually be caused by delayed effects of the juvenile environment. More generally, the results are important for understanding the mechanisms of delayed life-history effects as well as recognizing their population dynamic consequences.

Food resources and intestinal parasites as limiting factors for boreal vole populations during winter

“…This effect was again mediated by reproduction, which although marginal, was clearly more prevalent in food supplemented than nonsupplemented populations. This finding is consistent with previous research that has shown high quality food resources to facilitate winter reproduction in voles (Kaikusalo and Tast 1984), as well as advance the onset of spring reproduction (Taitt and Krebs 1981, Haapakoski et al 2012, Helle et al 2012.…”

“…A common line of differentiation is between intrinsic (for example age structure and maternal or juvenile environment: see [60][61][62][63]) and extrinsic factors (the environment, including predation: see [6,9]. However, recent transplant experiments have provided compelling evidence to support an important effect of the immediate environment on the life history traits of voles [64][65] (see however [63]). Our identification of diet quality limitation on increasing vole populations is consistent with the latter findings.…”

Mitochondrial uncoupling as a regulator of life history trajectories in birds: An experimental study in the zebra finch

“…Hence, one main function of mitochondria is to couple respiration (i.e. O 2 consumption) and nutrient oxidation to ATP synthesis, but interestingly, this coupling (also defined as mitochondrial efficiency) demonstrates a certain degree of plasticity (Brand, 2000;Divakaruni and Brand, 2011;Helle et al, 2012).…”

Relative Role of Dispersal Dynamics and Competition in Niche Breadth

“…These individual differences allow for variation in diet among individuals exposed to the same local conditions. Past events can influence the current state of individuals and alter their feeding needs and diets (Beckerman et al 2002, Ehrlen 2000, Helle et al 2012, Tanner et al 1996, Tanner et al 2011. Also, variation in prey in local environments can affect among-individual variation in consumers (Matthews and Mazumder 2004).…”

“…All niche-use theories assume that past conditions at a site affect current conditions, and are the basis for predicting future actions of individuals (Beckerman et al 2002, Ehrlen 2000, Helle et al 2012, Tanner et al 1996, Tanner et al 2011. However, among mobile species inhabiting landscapes with multiple 'sites,' a simple alternative explanation for among-individual variation is that diet resources differed in the environments from which they dispersed (Tilman 1994).…”