Sensitivity of Daphnia species to phosphorus-deficient diets

Abstract

The life history of freshwater cladocerans such as Daphnia spp. is strongly affected by their environment. Factors such as temperature, food quantity and even the presence or absence of predators influence growth, reproduction and morphology of individuals. Recently, it has also become clear that the quality of the food can affect various life history traits of Daphnia. More specifically, the effect of the elemental composition of algae, expressed as the C:P ratio, has been studied intensively. Daphnia species differ in their response to differences in the C:P ratio of their food. Until now, it has been unclear whether these species differences are driven by phylogenetic constraints or by adaptation to particular environmental conditions. Here we present laboratory experiments with 12 Daphnia species from three different subgenera originating from a broad range of habitats. We compared somatic growth rates and sensitivity to variation in the nutrient stoichiometry of the food with habitat parameters, taking into account the phylogenetic history of the species. No associations between fitness and habitat parameters were detected. However, we found a trade-off between sensitivity to P-deficient diets and the maximum growth rate on a P-sufficient diet. In several cases, this trade-off helps to explain the association between species distribution and habitat parameters. We observed no correlation of the sensitivity to P limitation with the phylogenetic history of the genus Daphnia. Thus, we conclude that the differential responses among Daphnia species to variation in P content in food were driven mainly by adaptations to their local habitats, and are not constrained by deep evolutionary patterns.

Joint effect of phosphorus limitation and temperature on alkaline phosphatase activity and somatic growth in Daphnia magna

“…Animals experiencing extreme P limitation exhibit decreases in RNA production and somatic growth along with other physiological malfunctions (Brett et al 2000; Elser et al 2001; Hessen et al 2002; Vrede et al 2002; Seidendorf et al 2009). In our study, the down-regulation of AP activity within the body of highly P-limited animals might be due to a decrease in RNA concentrations followed by a general decrease in the efficiency of transcription processes, consequently causing not only a smaller body size phenotype but also impairment of protein synthesis, including the AP enzyme.…”

Food quality and food threshold: implications of food stoichiometry to competitive ability of herbivore plankton

“…Consumer species with higher body P content would therefore grow faster when the P content of food is high (Main et al 1997, Elser et al 2000b), but they are likely to be more vulnerable to P deficiency in the food especially in aquatic habitats Hessen 1994, Sterner and. Indeed, Seidendorf et al (2010) showed that among Daphnia, key herbivore consumers in lakes and ponds, the species with higher growth rates under favorable food conditions decreased their growth rates by greater degrees when fed low P food. However, a species with greater sensitivity to change in P content of food does not necessarily mean that it is an inferior competitor under conditions of low P food, because the growth rate of the species can be still higher than that of a slow growing species.…”

Competitive outcomes between herbivorous consumers can be predicted from their stoichiometric demands

“…Since it is often in short supply in aquatic ecosystems, and since it is an important element constituting ribosomal RNA where protein synthesis takes place (Sterner and Elser 2002), the supply of P relative to energy or C is crucial for determining growth rates of not only plants but also animals. A number of studies have shown that a low P food slows down growth rates of key freshwater zooplankton (Urabe et al 1997, DeMott 1998, Sterner et al 1998, Urabe et al 2002, Seidendorf et al 2010, but the effect of Pdeficiency differs among taxa Pape 2005, Ferrão-Filho et al 2007, Iwabuchi andUrabe, submitted ). Some studies have reported that the dominant cladoceran species in nature seasonally changes due to changes in abundance and composition of algae, which were presumably different in nutrient content and digestibility (DeMott 1983, Hoenicke and Goldman 1987, Hu and Tessier 1995.…”