Adaptive phenotypic plasticity and local adaptation for temperature tolerance in freshwater zooplankton

Abstract

Many organisms have geographical distributions extending from the tropics to near polar regions or can experience up to 308C temperature variation within the lifespan of an individual. Two forms of evolutionary adaptation to such wide ranges in ambient temperatures are frequently discussed: local adaptation and phenotypic plasticity. The freshwater planktonic crustacean Daphnia magna, whose range extends from South Africa to near arctic sites, shows strong phenotypic and genotypic variation in response to temperature. In this study, we use D. magna clones from 22 populations (one clone per population) ranging from latitude 08 (Kenya) to 668 North (White Sea) to explore the contributions of phenotypic plasticity and local adaptation to high temperature tolerance. Temperature tolerance was studied as knockout time (time until immobilization, T imm ) at 378C in clones acclimatized to either 208C or 288C. Acclimatization to 288C strongly increased T imm , testifying to adaptive phenotypic plasticity. At the same time, T imm significantly correlated with average high temperature at the clones' sites of origin, suggesting local adaptation. As earlier studies have found that haemoglobin expression contributes to temperature tolerance, we also quantified haemoglobin concentration in experimental animals and found that both acclimatization temperature (AccT) and temperature at the site of origin are positively correlated with haemoglobin concentration. Furthermore, Daphnia from warmer climates upregulate haemoglobin much more strongly in response to AccT, suggesting local adaptation for plasticity in haemoglobin expression. Our results show that both local adaptation and phenotypic plasticity contribute to temperature tolerance, and elucidate a possible role of haemoglobin in mediating these effects that differs along a cold-warm gradient.

Parasitism drives host genome evolution: Insights from thePasteuria ramosa-Daphnia magnasystem

“…magna has become a model for research in coevolution, in particular with the bacteria P. ramosa (Decaestecker et al 2007;Ebert 2008), a highly virulent and widespread parasite that often dominates parasite communities in Daphnia populations (Stirnadel and Ebert 1997;Decaestecker et al 2007). In addition, D. magna populations are known to be locally adapted to many other environmental cues, such as temperature, salinity, and predation (Wilson and Hebert 1992;DeMeester 1993;Yampolsky et al 2014), which would also leave traces of selection in the genome. However, as the Daphnia system is also known for a large number of other parasites, which might also be involved in coevolutionary dynamics (Duffy and Sivars-Becker 2007;Ebert 2008;Caceres et al 2014), one might expect to see further signatures of selection along the genome.…”

Geographic variation in thermal physiological performance of the intertidal crabPetrolisthes violaceusalong a latitudinal gradient

“…Phenotypic plasticity and/or local adaptation to thermal clines can cause different patterns of thermal performance across the geographic range of an ectothemic species (Gardiner et al, 2010;Huey and Kingsolver, 1989;Knies et al, 2009;Schulte et al, 2011;Yampolsky et al, 2014). These patterns can be explained by at least four theoretical models of thermal evolution (Angilletta et al, 2002;Gardiner et al, 2010).…”

Reduced up-regulation of gene expression in response to elevated temperatures in the mid-Atlantic population of Calanus finmarchicus

“…Such variation in a species ability to cope with diverse environmental pressure has been shown to be a result of phenotypic plasticity (Lardies and Bozinovic, 2008) and/or local adaptation (Yampolsky et al, 2014). At this stage it is difficult to identify which mechanism plays the main role in temperature response in C. finmarchicus, however evidence suggest that both mechanisms may be at play.…”