Local thermal adaptation detected during multiple life stages across populations ofDrosophila melanogaster

Abstract

Thermal adaptation is typically detected by examining the tolerance of a few populations to extreme temperatures within a single life stage. However, the extent to which adaptation occurs among many different populations might depend on the tolerance of multiple life stages and the average temperature range that the population experiences. Here, we examined local adaptation to native temperature conditions in eleven populations of the well‐known cosmopolitan fruit fly, Drosophila melanogaster. These populations were sampled from across the global range of D. melanogaster. We measured traits related to fitness during each life stage to determine whether certain stages are more sensitive to changes in temperature than others. D. melanogaster appeared to show local adaptation to native temperatures during the egg, larval and adult life stages, but not the pupal stage. This suggests that across the entire distribution of D. melanogaster, certain life stages might be locally adapted to native temperatures, whereas other stages might use phenotypic plasticity or tolerance to a wide range of temperatures experienced in the native environment of this species.

Parallel and Population-specific Gene Regulatory Evolution in Cold-Adapted Fly Populations

“…The adults are mobile; their primary role is mating and reproduction (Powell, 1997;Sokolowski et al 1986), and it is thought to be the primary overwintering stage in seasonally cold environments (Lzquierdo 1991). And a recent study using D. melanogaster populations across the globe found local adaptation to thermal environments at egg, larval and adult stages but not the pupal stage (Austin and Moehring 2019). Therefore, we may expect a different level of parallel gene expression evolution for thermal environments for the pupal stage.…”

Beneficial developmental acclimation in reproductive performance under cold but not heat stress

“…These findings emphasize the importance of analysing several traits in all stages of the life cycle to better characterize the thermal limits of populations (e.g. see Austin & Moehring, 2019). Some authors have called for caution when studying developmental plasticity effects on the adult response, due to the possible confounding effects of selection at the juvenile stages as a result of differential mortality across thermal environments (Santos et al, 2019).…”

“…Evidence for this has been equivocal, with some studies indicating non-parallel reactions norms , and thus suggesting genetic variation for plasticity (e.g. (Angilletta et al, 2019;Austin and Moehring, 2019;Clemson et al, 2016;Fallis et al, 2014;Klepsatel et al, 2019;Mathur and Schmidt, 2017;Rajpurohit and Schmidt, 2016;Sarup and Loeschcke, 2010), and others showing no plasticity differences among populations (e.g. Cooper et al, 2012;Klepsatel et al, 2013;Clemson et al, 2016).…”

“…Variation in thermal plasticity may also occur across life stages, particularly in holometabolous insects (Sgrò et al, 2016;Porcelli et al, 2017;Austin & Moehring, 2019). Plastic changes during the developmental stage may have persistent effects in the thermal performance of adults (Beaman et al, 2016;Kellermann et al, 2017).…”

High developmental temperature leads to low reproduction despite adult temperature

“…An increasing number of experiments is starting to address more thoroughly the developmental thermal plasticity associated with adult life-history traits, mainly in ectotherms (Angilletta et al, 2019;Austin and Moehring, 2019;Cao et al, 2018;Klepsatel et al, 2019;Klockmann et al, 2017;Kristensen et al, 2012;Manenti et al, 2017;Porcelli et al, 2017;Zamorano et al, 2017). This is extremely relevant as traits closely related to fitness, such as fecundity and longevity, are crucial for population persistence and likely to be affected by climate change (Walsh et al, 2019).…”