Dietary lipid quality affects temperature-mediated reaction norms of a freshwater key herbivore
- 380 Downloads
Temperature-mediated plasticity in life history traits strongly affects the capability of ectotherms to cope with changing environmental temperatures. We hypothesised that temperature-mediated reaction norms of ectotherms are constrained by the availability of essential dietary lipids, i.e. polyunsaturated fatty acids (PUFA) and sterols, as these lipids are involved in the homeoviscous adaptation of biological membranes to changing temperatures. A life history experiment was conducted in which the freshwater herbivore Daphnia magna was raised at four different temperatures (10, 15, 20, 25°C) with food sources differing in their PUFA and sterol composition. Somatic growth rates increased significantly with increasing temperature, but differences among food sources were obtained only at 10°C at which animals grew better on PUFA-rich diets than on PUFA-deficient diets. PUFA-rich food sources resulted in significantly higher population growth rates at 10°C than PUFA-deficient food, and the optimum temperature for offspring production was clearly shifted towards colder temperatures with an increased availability of dietary PUFA. Supplementation of PUFA-deficient food with single PUFA enabled the production of viable offspring and significantly increased population growth rates at 10°C, indicating that dietary PUFA are crucial for the acclimation to cold temperatures. In contrast, cumulative numbers of viable offspring increased significantly upon cholesterol supplementation at 25°C and the optimum temperature for offspring production was shifted towards warmer temperatures, implying that sterol requirements increase with temperature. In conclusion, essential dietary lipids significantly affect temperature-mediated reaction norms of ectotherms and thus temperature-mediated plasticity in life history traits is subject to strong food quality constraints.
KeywordsDaphnia Food quality Phenotypic plasticity Polyunsaturated fatty acids Sterols
We thank P. Merkel for technical assistance. E. Sperfeld and N. Schlotz provided valuable comments on an earlier draft of this manuscript.
- Colbourne JK, Pfrender ME, Gilbert D, Thomas WK, Tucker A, Oakley TH, Tokishita S, Aerts A, Arnold GJ, Basu MK, Bauer DJ, Cáceres CE, Carmel L, Casola C, Choi J-H, Detter JC, Dong Q, Dusheyko S, Eads BD, Fröhlich T, Geiler-Samerotte KA, Gerlach D, Hatcher P, Jogdeo S, Krijgsveld J, Kriventseva EV, Kültz D, Laforsch C, Lindquist E, Lopez J, Manak JR, Muller J, Pangilinan J, Patwardhan RP, Pitluck S, Pritham EJ, Rechtsteiner A, Rho M, Rogozin IB, Sakarya O, Salamov A, Schaack S, Shapiro H, Shiga Y, Skalitzky C, Smith Z, Souvorov A, Sung W, Tang Z, Tsuchiya D, Tu H, Vos H, Wang M, Wolf YI, Yamagata H, Yamada T, Ye Y, Shaw JR, Andrews J, Crease TJ, Tang H, Lucas SM, Robertson HM, Bork P, Koonin EV, Zdobnov EM, Grigoriev IV, Lynch M, Boore JL (2011) The ecoresponsive genome of Daphnia pulex. Science 331:555–561. doi: 10.1126/science.1197761 PubMedCrossRefGoogle Scholar
- Crockett EL (1998) Cholesterol function in plasma membranes from ectotherms: membrane-specific roles in adaptation to temperature. Am Zool 38:291–304Google Scholar
- Farkas T (1979) Adaptation of fatty-acid compositions to temperature—a study on planktonic crustaceans. Comp Biochem Physiol 64B:71–76Google Scholar
- Jüttner F, Leonhardt J, Möhren S (1983) Environmental factors affecting the formation of mesityloxid, dimethylallylic alcohol and other volatile compounds excreted by Anabaena cylindrica. J Gen Microbiol 129:407–412Google Scholar
- Stanley DW (2000) Eicosanoids in invertebrate signal transduction systems. Princeton University Press, PrincetonGoogle Scholar
- Zar JH (2010) Biostatistical analysis. Prentice Hall/Pearson, LondonGoogle Scholar