Universität zu Köln

Werner, Christian ORCID: 0000-0001-9214-7322, Otte, Kathrin A. and von Elert, Eric ORCID: 0000-0001-7758-716X (2021). Phenotypic convergence in a natural Daphnia population acclimated to low temperature. Ecol. Evol., 11 (21). S. 15312 - 15325. HOBOKEN: WILEY. ISSN 2045-7758

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Abstract

Fluidity of a given membrane decreases at lower ambient temperatures, whereas it rises at increasing temperatures, which is achieved through changes in membrane lipid composition. In consistence with homeoviscous adaptation theory, lower temperatures result in increased tissue concentrations of polyunsaturated fatty acids (PUFAs) in Daphnia magna, suggesting a higher PUFA requirement at lower temperatures. However, so far homeoviscous adaptation has been suggested for single or geographically separated Daphnia genotypes only. Here, we investigated changes in relative fatty acid (FA) tissue concentrations in response to a lower temperature (15 degrees C) within a D. magna population. We determined juvenile growth rates (JGR) and FA patterns of 14 genotypes that were grown on Chlamydomonas klinobasis at 15 degrees C and 20 degrees C. We report significant differences of JGR and the relative body content of various FAs between genotypes at either temperature and between temperatures. Based on slopes of reaction norms, we found genotype-specific changes in FA profiles between temperatures suggesting that genotypes have different strategies to cope with changing temperatures. In a hierarchical clustering analysis, we grouped genotypes according to differences in direction and magnitude of changes in relative FA content, which resulted in three clusters of genotypes following different patterns of changes in FA composition. These patterns suggest a lower importance of the PUFA eicosapentaenoic acid (EPA, C20:5 omega 3) than previously assumed. We calculated an unsaturation index (UI) as a proxy for membrane fluidity at 15 degrees C, and we neither found significant differences for this UI nor for fitness, measured as JGR, between the three genotype clusters. We conclude that these three genotype clusters represent different physiological solutions to temperature changes by altering the relative share of different FAs, but that their phenotypes converge with respect to membrane fluidity and JGR. These clusters will be subjected to different degrees of PUFA limitation when sharing the same diet.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Werner, Christian UNSPECIFIED orcid.org/0000-0001-9214-7322 UNSPECIFIED Otte, Kathrin A. UNSPECIFIED UNSPECIFIED UNSPECIFIED von Elert, Eric UNSPECIFIED orcid.org/0000-0001-7758-716X UNSPECIFIED
URN:	urn:nbn:de:hbz:38-563986
DOI:	10.1002/ece3.8217
Journal or Publication Title:	Ecol. Evol.
Volume:	11
Number:	21
Page Range:	S. 15312 - 15325
Date:	2021
Publisher:	WILEY
Place of Publication:	HOBOKEN
ISSN:	2045-7758
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language POLYUNSATURATED FATTY-ACIDS; FOOD QUALITY; LIPID-COMPOSITION; HOMEOVISCOUS ADAPTATION; EICOSAPENTAENOIC ACID; PHOSPHORUS LIMITATION; TOXIC CYANOBACTERIA; THERMAL TOLERANCE; GENE-EXPRESSION; LIFE-HISTORIES Multiple languages Ecology; Evolutionary Biology Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/56398