Temperature and the effects of elemental food quality on Daphnia

Abstract

1. We examined the responses of two species of Daphnia to changes in food phosphorus (P) content, with animals reared at three different water temperatures. Specifically, we measured mass-specific growth rate (MSGR), body P content and respiration rate of Daphnia magna and Daphnia pulex acclimatised to 10, 17.5 and 25°C and fed food carbon : phosphorus (C : P) ratios of either 150 or 500. 2. The responses of these three physiological variables to temperature-food quality interactions were species-specific. There was a significant interactive effect of temperature and food quality on D. magna, as the greatest proportional effect of food quality on growth was observed at 10°C and reductions in body P because of low food P content were relatively greater at 25°C. These effects may reflect the temperature dependence of mechanisms that reduce elemental constraints associated with food quality in D. magna. By contrast, there were no interactive effects between food quality and temperature on MSGR, body P or mass-specific respiration of D. pulex. 3. It thus appears that temperature can alter food quality effects on Daphnia but the nature of these alterations depends upon the daphniid species and its thermal adaptability. Significant temperature-food quality interactions will complicate efforts to understand zooplankton nutrition in nature and warrant future consideration.

Unifying ecological stoichiometry and metabolic theory to predict production and trophic transfer in a marine planktonic food web

“…Persson et al [33] found no evidence of Daphnia P limitation at the lowest temperature (108C), indicating that enzyme kinetics or other measures of food quality were more important for somatic Daphnia growth than the demands for P to RNA and protein. By contrast, McFeeters & Frost [43] demonstrated that the effects of high C : P on the growth of Daphnia magna decreased with temperature and noted that contrasting results may suggest that at low temperatures thermal constraints can reduce or mask the effects of poor food quality. All these findings and the results of our study imply that in order to assess stoichiometric food quality effects on natural zooplankton populations, the in situ temperature needs to be taken into account.…”

Temperature reaction norms ofDaphnia carinatafitness: the effects of food concentration, population density, and photoperiod

“…Considerable evidence exists for clonal-and species-specific responses in daphniids (Jiang et al forthcoming 2013). For example, the responses of physiological variables to temperature-food quality interactions reported by McFeeters and Frost (2011) were restricted to one of the two Daphnia species studied. Further studies are needed to investigate whether the effects of ecological variables in temperature reaction norms are clonal and/or species specific.…”

Seasonality in the trophic basis of a temperate stream invertebrate assemblage: Importance of temperature and food quality

“…Thus, during cold months, the availability of high-quality resources may not be as critical, because temperature likely limits the growth rates of consumers and ingested resources are largely dedicated to fueling basal metabolism instead of new tissue growth. Others, however, have shown that food quality effects on growth may be greater at cold temperatures and can vary across species (McFeeters and Frost 2011). Such an effect may be driven by constraints on physiological mechanisms for countering poor food quality at cold temperatures.…”