Rapid within- and transgenerational changes in thermal tolerance and fitness in variable thermal landscapes

Abstract

Phenotypic plasticity allows organisms to cope with variable environmental conditions increasing both performance and fitness. We studied within-generation plasticity and transgenerational effects of thermal conditions on temperature tolerance and demographic parameters in Drosophila melanogaster. We employed a fully factorial design, in which both parental (P) and offspring generations (F1) were reared in a constant or a variable thermal environment. Thermal variability during ontogeny increased heat tolerance in P, but with demographic cost as this treatment resulted in substantially lower survival, fecundity and net reproductive rate. The adverse effects of thermal variability (V) on demographic parameters were less drastic in flies from the F1, which exhibited higher net reproductive rates than their parents. These compensatory responses could not totally overcome the challenges of the thermally variable regime, contrasting with the offspring of flies raised in a constant temperature (C) that showed no reduction in fitness with thermal variation. Thus, the parental thermal environment had effect on thermal tolerance and demographic parameters in fruit-fly. These results demonstrate how transgenerational effects of environmental conditions on heat tolerance, as well as their potential costs on other fitness components, can have a major impact on populations' resilience to warming temperatures and more frequent thermal extremes.

Transgenerational exposure to marine heatwaves ameliorates the lethal effect on tropical copepods regardless of predation stress

“…Most importantly, our results suggest that P. incisus may evolve rapidly and complete TGP to MHW, with full amelioration of its lethal effect in the second generation. The transgenerational plasticity of MHWs comes with a cost of reduced reproduction, and grazing may be a crucial and widespread mechanism for marine invertebrates coping with the transient effects of heatwaves (Cavieres et al, 2020; Dinh et al, 2020; Doan et al, 2019). Interestingly, fish predator cues played a minor role in shaping both immediate and transgenerational effects of MHWs, highlighting the dominant effects of MHWs on P. incisus .…”

Thermal acclimation to warmer temperatures can protect host populations from both further heat stress and the potential invasion of pathogens

“…This highlights how thermal acclimation can have opposing impacts on thermal stress resistance and other fitness related traits for both hosts and pathogens (e.g. Cavieres et al 2020).…”

“…In turn for a pathogen, estimates of infection success and proliferation can be integrated via an epidemiological model into the basic reproduction number, R 0 , which captures the potential of a pathogen to spread through a completely susceptible host population (Anderson and May 1986). Rarely, however, has the impact of thermal acclimation on thermal stress resistance been considered in unison with metrics of how well a host or pathogen population might perform (Klockmann et al 2017; Cavieres et al 2020). Evidence for whether thermal acclimation improves or impairs thermal stress resistance when a host is simultaneously exposed to disease is likewise limited (see Greenspan et al 2017).…”

“…Rarely, however, has the impact of thermal acclimation on thermal stress resistance been considered in unison with metrics of how well a host or pathogen population might perform (Klockmann et al 2017;Cavieres et al 2020). Evidence for whether thermal acclimation improves or impairs thermal stress resistance when a host is simultaneously exposed to disease is likewise limited (see Greenspan et al 2017).…”