Plasticity of growth rate and metabolism in Daphnia magna populations from different thermal habitats

Abstract

The aim of this study was to evaluate the effect of temperature on growth and aerobic metabolism in clones of Daphnia magna from different thermal regimes. Growth rate (increment in size), somatic juvenile growth rate (increment in mass), and oxygen consumption were measured at 15 and 25 degrees C in 21 clones from one northern and two southern sites. There were no significant differences in body size and growth rate (increase in length) at both 15 and 25 degrees C among the three sites. Clones from southern site 2 had a higher mass increment than clones from the other two sites at both temperatures. Clone had a significant effect on growth (body length) and body size at both temperatures. As expected, age at maturity was lower at 25 degrees C (4.5 days) than at 15 degrees C, (11.6 days) and body sizes, after the release of the third clutch, were larger at 15 degrees C than at 25 degrees C. Northern clones had higher oxygen consumption rates and specific dynamic action (SDA) than southern clones at 15 degrees C. By contrast, southern clones from site 1 had a higher oxygen consumption and SDA than subarctic clones at 25 degrees C. Clones from southern site 2 had high oxygen consumption rates at both temperatures. Our results reveal important differences in metabolic rates among Daphnia from different thermal regimes, which were not always reflected in growth rate differences.

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

“…For example, Mitchell & Lampert [25] observed that southern clones have a higher growth rate at 20-238C, but do not differ from the northern clones in the shape of growth rate reaction norm, which led them to conclude that among-population differences are not a manifestation of local adaptation. Chopelet et al [24] found evidence of higher oxygen consumption by southern clones at higher temperatures and vice versa, but this correlation was evident for only one of the two southern locations they sampled. Thus, local thermal adaptation and its possible mechanisms have been elusive in Daphnia studies.…”

“…Among them, studies of geographical variation in Daphnia have provided evidence for both phenotypic plasticity and genetic population differentiation [22][23][24][25]. However, despite ample genetic variation among genotypes and populations, no evidence for local adaptation was found in this system.…”

Genetic variability in the tolerance of natural populations ofSimocephalus vetulus(Müller, 1776) to lethal levels of sodium chloride

“…In this study, we used a simple and cost-effective technique (MSP-PCR), which allowed satisfactory discrimination of genotypes (clones), analogously to RAPD (e.g., Weber and Declerck, 1997), microsatellite (e.g., Chopelet et al, 2008), or allozyme (e.g., Weider and Hebert, 1987) analyses. However, a conservative approach was needed, both in terms of band profile analysis and dissimilarity cut-off level, in order to avoid false positives (i.e., scoring identical genotypes as distinct).…”

Heat tolerance, temperature acclimation, acute oxidative damage and canalization of haemoglobin expression in Daphnia

“…Since the classic Daphnia study in which the term ''reaction norm'' was first formulated (Woltereck 1909), a plethora of Daphnia reaction norm data has been obtained, including those on plasticity of morphological characters (e.g. Jacobs 1987; Spitze and Sadler 1996;Boersma et al 1998;Tollrian and Heibl 2004;Spanier et al 2010;Miyakawa et al 2010), life-history traits (Lynch 1980;Spitze 1992;Ebert et al 1993;Yampolsky and Ebert 1994;Spitze and Sadler 1996;Boersma et al 1998;Weetman and Atkinson 2004;Latta et al 2007;Chopelet et al 2008;Beckerman et al 2010) and tolerance to pollutants (Coors et al 2004;Messiaen et al 2010), which Daphnia exhibit in response to a wide variety of environmental factors, from temperature and food availability to the presence of predators, parasites or pollutants.…”