Universität zu Köln

Hahn, Meike Anika and Von Elert, Eric (2020). The impact of diel vertical migration on fatty acid patterns and allocation in Daphnia magna. PeerJ, 8. LONDON: PEERJ INC. ISSN 2167-8359

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Abstract

In freshwater zooplankton diel vertical migration (DVM) is a widespread predator-avoidance behavior that is induced by kairomones released from fish. Thereby zooplankton reduces predation by fish by staying in deep and dark colder strata during daytime and migrating into warmer layers during night, and thus experiences diel alterations in temperature. Constantly lower temperatures have been shown to increase the relative abundance of polyunsaturated fatty acids (PUFAs) in Daphnia sp. Furthermore, a low dietary supply of the omega 3-PUFA eicosapentaenoic acid (EPA) has been shown to limit the induction of DVM in Daphnia magna and the performance of D. magna under fluctuating temperatures, as experienced during DVM. In nature DVM of D. magna in response to fish is accompanied by the presence of fish-borne kairomone and diel fluctuations of depth dependent-parameters like temperature, food, and oxygen supply. Here we investigated the effect of factors, which are differing between Daphnia that perform DVM and those which do not. We selected to examine the effect of changing temperature and light conditions and of the presence/absence of fish kairomones on D. magna. For this purpose, we conducted a full factorial experimental design in which we grew D. magna under constantly warm temperatures in a diel light-dark regime or under alternating temperatures in darkness crossed with the presence or absence of fish kairomones. We analyzed the fatty acid composition of mature animals and of their offspring in each treatment. Simulation of the light and temperature regime of migrating animals in presence of the fish kairomone resulted in an increased relative allocation of the omega 3-PUFA EPA, from adult animals to their offspring, manifesting as decreased EPA concentrations in mothers and increased EPA concentrations in their offspring in response to simulated DVM (mothers). Additionally, EPA concentrations in the offspring were affected by the interaction of simulated DVM and the fish cue. The presence of the fish kairomone alone increased the EPA concentration in the offspring, that was not experiencing simulated DVM. These findings lead to the conclusion that the temperature and light regime associated with DVM alone, as well as in combination with the DVM-inducing fish kairomones, alter the allocation of fatty acids to the offspring in a manner, which is beneficial for the offspring under the decreased average temperatures, which migrating animals are exposed to. A low dietary supply of omega 3-PUFAs may constrain D. magna's amplitude of DVM, but our results suggest that the next generation of animals may be capable of regaining the full DVM amplitude due to the effect of the fish kairomone and the experienced temperature fluctuations (and darkness) on tissue fatty acid composition. These findings suggest that fatty acid limitation in DVM performing Daphnia may be more severe for the maternal than for the offspring generation.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Hahn, Meike Anika UNSPECIFIED UNSPECIFIED UNSPECIFIED Von Elert, Eric UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-336885
DOI:	10.7717/peerj.8809
Journal or Publication Title:	PeerJ
Volume:	8
Date:	2020
Publisher:	PEERJ INC
Place of Publication:	LONDON
ISSN:	2167-8359
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language FRESH-WATER HERBIVORE; ADAPTIVE SIGNIFICANCE; LIPID-COMPOSITION; TEMPERATURE; ADAPTATION; ZOOPLANKTON; FOOD; PROSTAGLANDINS; PHYTOPLANKTON; CONSEQUENCES Multiple languages Multidisciplinary Sciences Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/33688