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Dr. Marion Mehlis-Rick

Wissenschaftliche Mitarbeiterin

Research Interests

During my diploma study at the Institute for Evolutionary Biology and Ecology in the research group of Prof. Bakker I examined the influence of kinship on the behaviour of three-spined sticklebacksMore specifically, I performed experiments on male brood-care and female mate-choice.


My PhD study focused on sperm competition in three-spined sticklebacks. Sperm competition occurs when two or more males compete to fertilize the female gametes. In three-spined sticklebacks sneaking is a well-known phenomenon and this leads to sperm competition and its evolutionary consequences. Therefore, I performed several behavioural experiments and morphological studies using microsatellites for the determination of fatherhood.


  • Vitt, S., Mehlis-Rick, M., Bakker, T. C. M. & Rick, I. P. (2019). Enhanced ambient UVB radiation affects post-mating, but not pre-mating sexual traits in a fish. Oecologia 190: 355-366.

  • Mehlis-Rick, M., Thünken, T., Krings, M., Käfer, S. & Rick, I. P. (2018) Cerebral lateralization and quantity discrimination abilities in the threespine stickleback (Gasterosteus aculaetus). Evol. Ecol. Res. 19:487-501.

  • Rystrom, T. L., Clement, V. F., Rick, I. P., Bakker, T. C. M. & Mehlis, M. (2018). Shoal sex composition and predation risk influence sub-adult threespine stickleback shoaling decisions. Behav. Processes (published online, DOI 10.1016/j.beproc.2018.06.009).

  • Hiermes, M., Rick, I. P., Mehlis, M. & Bakker, T. C. M. (2016). The dynamics of color signals in male threespine sticklebacks Gasterosteus aculeatus. Curr. Zool. 62: 23-31.

  • Hiermes, M., Bakker, T. C. M., Mehlis, M. & Rick, I. P. (2015). Context-dependent dynamic UV signaling in female threespine sticklebacks. Sci. Rep. 5:17474.

  • Mehlis, M., Rick, I. P. & Bakker, T. C. M. (2015). Dynamic resource allocation between pre- and postcopulatory episodes of sexual selection determines competitive fertilization success. Proc. R. Soc. B 282:20151279.

  • Mehlis, M., Thünken, T., Bakker, T. C. M. & Frommen, J. G. (2015). Quantification acuity in spontaneous shoaling decisions of three-spined sticklebacks. Anim. Cogn. 18:1125-1131.

  • Mehlis, M., Rahn, A. & Bakker, T. C. M. (2015). Sperm quality but not relatedness predicts sperm competition success in threespine sticklebacks (Gasterosteus aculeatus). BMC Evol. Biol. 15:74.

  • Hiermes, M., Mehlis, M., Rick, I. P. & Bakker, T. C. M. (2015). Habitat-dependent olfactory discrimination in three-spined sticklebacks (Gasterosteus aculeatus). Anim. Cogn. 18: 839-846

  • Mehlis, M. & Bakker, T. C. M. (2014). The influence of ambient water temperature on sperm performance and fertilization success in three-spined sticklebacks (Gasterosteus aculeatus). Evol. Ecol. 28:655-667.

  • Rick, I. P., Mehlis, M., Eßer, E. & Bakker, T. C. M. (2014). The influence of ambient ultraviolet light on sperm quality and sexual ornamentation in three-spined sticklebacks (Gasterosteus aculeatus). Oecologia 174: 393-402.

  • Bakker, T. C. M., Hollmann M., Mehlis, M. & Zbinden, M. (2014). Functional variation of sperm morphology in sticklebacks. Behav. Ecol. Sociobiol. 68: 617-627.

  • Mehlis, M., Hilke, L. K. & Bakker, T. C. M. (2013). Attractive males have faster sperm in three-spined sticklebacks Gasterosteus aculeatus. Curr. Zool. 59: 761-768.

  • Mehlis, M. & Bakker, T. C. M. (2013). Male reproductive traits of full-sibs of different age classes in three-spined sticklebacks (Gasterosteus aculeatus). SpringerPlus 2:175.

  • Frommen, J. G., Bakker, T. C. M., Proscurcin, L. C. & Mehlis, M. (2012). Gravidity-associated shoaling decisions in three-spined sticklebacks (Gasterosteus aculeatus). Ethology 118:1149-1156.

  • Mehlis, M., Frommen, J. G., Rahn, A. K. & Bakker, T. C. M. (2012). Inbreeding in three-spined sticklebacks (Gasterosteus aculeatus L.): effects on testis and sperm traits. Biol. J. Linn. Soc. 107: 510-520.

  • Rick, I. P., Mehlis, M. & Bakker, T. C. M.(2011). Male red ornamentation is associated with female red sensitivity in sticklebacks. PLoS One 6:e25554.

  • Frommen, J. G. , Herder, F., Engqvist, L., Mehlis, M., Bakker, T. C. M., Schwarzer, J. & Thünken, T. (2011). Costly plastic morphological responses to predator specific odour cues in three-spined sticklebacks (Gasterosteus aculeatus). Evol. Ecol. 25: 641-656.

  • Mehlis, M., Bakker, T. C. M., Engqvist, L. & Frommen, J. G. (2010). To eat or not to eat: egg-based assessment of paternity triggers fine-tuned decisions about filial cannibalism. Proc. R. Soc. Lond. B. 277: 2627-2635.

  • Mehlis, M., Bakker, T. C. M., Langen, K. & Frommen, J. G. (2009). Cain and Abel reloaded? Kin recognition and male-male aggression in three-spined sticklebacks (Gasterosteus aculeatus L.). J. Fish. Biol. 75: 2154-2162.

  • Frommen, J. G., Mehlis, M. & Bakker, T. C. M. (2009). Predator-inspection behaviour in female three-spined sticklebacks (Gasterosteus aculeatus L.) is associated with status of gravidity. J. Fish. Biol. 75: 2143-2153.

  • Mehlis, M., Bakker, T. C. M. & Frommen, J. G. (2009). Nutritional benefits of filial cannibalism in three-spined sticklebacks (Gasterosteus aculeatus). Naturwissenschaften 96: 399-403.

  • Mehlis, M., Bakker, T. C. M. & Frommen, J. G. (2008). Smells like sib spirit - Kin recognition in three-spined sticklebacks (Gasterosteus aculeatus) is mediated by olfactory cues. Anim. Cogn. 11: 643-650.

  • Frommen, J. G., Mehlis, M., Brendler, C. & Bakker, T. C. M. (2007). Shoaling decisions in sticklebacks - familiarity, kinship and inbreeding. Behav. Ecol. Sociobiol. 61: 533-539.


PhD Thesis

Mehlis, M. (2014). Sexually selected traits and reproductive performance in male three-spined sticklebacks (Gasterosteus aculeatus). PhD-thesis, University of Bonn, Germany.

Diploma Thesis

Mehlis, M. (2007). Der Einfluss von Verwandtschaft auf das Fortpflanzungsverhalten beim Dreistachligen Stichling (Gasterosteus aculeatus). Diploma-thesis, University of Bonn, Germany.