Marine Biology

, 165:82 | Cite as

The ability to incorporate functional plastids by the sea slug Elysia viridis is governed by its food source

  • Cessa Rauch
  • Aloysius G. M. Tielens
  • João Serôdio
  • Sven B. Gould
  • Gregor Christa
Original paper


Functional kleptoplasty in sacoglossan sea slugs is among the most curious photosynthetic associations known. One member of these marine molluscs, Elysia viridis, is known to incorporate plastids from a variety of different algae food sources, but with apparently different outcomes and differences in the time span of the retention of functional kleptoplasts. While it was previously shown that kleptoplasts that stem from Codium tomentosum are kept functional for several weeks (long-term retention, LtR), those that stem from Bryopsis hypnoides or Cladophora rupestris are thought to be of limited use regarding photosynthetic capacity (short-term retention, StR). This is important, because it touches upon the popular yet controversial question of how important photosynthesis is for the thriving of these slugs. The aim of the present study was to determine to what degree the plastid source determines retention time. We, therefore, compared E. viridis feeding on either Cladophora sp. or B. hypnoides. We show that kleptoplasts of B. hypnoides incorporate 14CO2, but with rapidly declining efficiency throughout the first week of starvation, while the plastids of Cladophora sp. are, surprisingly, not incorporated to begin with. The radulae of the different samples showed adjustment to the food source, and when feeding on Cladophora sp., E. viridis survived under laboratory conditions under both starvation and non-starvation conditions. Our results demonstrate that (i) the ability to incorporate plastids by E. viridis differs between the food sources B. hypnoides and Cladophora sp., and (ii) photosynthetic active kleptoplasts are not an inevitable requirement for survival.



Funding through the DAAD (P.R.I.M.E.) and FCT to GC (SFRH/BPD/109892/2015), DFG to S.B.G. (GO1825/4-1), and through the ERC to Prof. William F. Martin (ERC 666053) is gratefully acknowledged. For financial support, thanks are due to Centre for Environmental and Marine Studies (UID/AMB/50017), FCT/Ministry of Science and Education through national funds, and the co-funding by European Fund For Regional Development, within the PT2020 Partnership Agreement and Compete 2020.

Author contributions

CR, SBG, JS and GC planned the experiments, which were conducted by CR, AGMT and GC. CR, SBG and GC wrote the manuscript, whose final version was approved by all authors. We thank Steffen Köhler (CAi, HHU) for imaging of the slugs and for his help with SEM imaging, and Marion Nissen (CAi, HHU) for her help with the TEM.

Compliance with ethical standards

Ethical approval

All applicable international, national, and/or institutional guidelines for the care and use of animals were followed.

Conflict of interest

The authors declare no competing interests.

Supplementary material

227_2018_3329_MOESM1_ESM.pdf (73 kb)
Supplementary material 1 (PDF 72 kb)


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© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Institute for Molecular Evolution, Heinrich-Heine-University DüsseldorfDüsseldorfGermany
  2. 2.Department of Biochemistry and Cell Biology, Faculty of Veterinary MedicineUtrecht UniversityUtrechtThe Netherlands
  3. 3.Department of Medical Microbiology and Infectious DiseasesErasmus University Medical CenterRotterdamThe Netherlands
  4. 4.Department of Biology, Centre for Environmental and Marine Studies (CESAM)University of AveiroAveiroPortugal

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