Der Zusammenhang zwischen 'Rot'-Sehen und Herbivorie: vom Gen zum Verhalten
Kognitive, systemische und Verhaltensneurobiologie
Molekulare Biologie und Physiologie von Nerven- und Gliazellen
Zusammenfassung der Projektergebnisse
Coral reef fishes live in very colourful environments, are species-rich, diverse in ecology and behaviour, and show a remarkable degree of variability in colours and colour patterns. Colour vision plays a major role in their daily lives and they use vision to find food or recognize mates and foes. The great diversity of colouration and well-adapted visual systems makes them ideal candidates to study the influences of ecological traits on both colouration and the visual system. At the core of vision are the light absorbing visual pigments (opsins) - embedded in retinal photoreceptors - that determine the spectral sensitivities of an organism. Teleost fishes in general have become powerful models to study visual adaptations that can be linked to specific behaviours such as foraging and mating. Results of this DFG funded project studying vision in coral reef fishes from the Great Barrier Reef with main focus on the colourful and diverse damselfishes (Pomacentridae) demonstrated that sensitivity to red as indicated by the expression of the long-wavelength-sensitive opsin gene (LWS) is favoured in algivores and also red-coloured species. Visual models indicated that being sensitive to red does indeed enhance the ability to detect long-wavelength reflecting algae, and red-coloured conspecifics possibly enabling social signalling. It has been much of supposition about why coral reef are colourful, but it largely remains an unanswered question. Results of this project suppose a sensory bias to foraging that then leads to the evolution of red colouration, and thus reveals how phenotypic differences in ecological traits and differences in visual sensitivities might eventually explain the variation in colouration among colourful reef fishes. Moreover, results of this project highlighted that UV vision in damselfishes is highly tuned. Interestingly, not only did all species investigated so have UV-transmissive lenses, express the ‘UV- sensitive’ SWS1 opsin gene and most species reflect in the UV, only transcriptomic studies being conducted in the course of this project highlighted that SWS1 is split in two main copies across the damselfish phylogeny producing proteins that fall into two different sensitivities, and being alternatively expressed. Furthermore, this project also revealed a novel visual specialisation in the retina of anemonefish that form with their contrasting colour patterns (orange and white patterning) and specialized mode of life (living in symbiosis with anemones and being sequential hermaphrodites), a unique group within damselfishes. Retinal topographic maps using fluorescent in situ hybridization visualized a segregated small fraction of single cones coexpressing the UV SWS1 with the violet SWS2B, supposed to help the detection of the host anemone and conspecifics based on colour patterns. Together, outcomes of this study underpin the hypothesis that damselfishes use a close-range ‘private’ communication channel that is likely hidden from ‘UV-blind’ predators. This highly tuned UV-channel is not only hidden to predators but also to us UV-blind humans, thus enabling us to view the world through a different perspective possible inspiring to new ideas and technologies. Findings from Stieb et al. (2019, Scientific Reports) are covered in 20+ mainstream media articles including EurekAlert.org (Finding nemo’s cousin), Cosmos magazine (Nemo’s cousins have a special way of finding him), SciNews.com (Anemonefish Can See Ultraviolet Light), Science daily (Finding Nemo’s Cousins: Meet the Little Fish That Can See UV Light), and Daily Mail UK (How Nemo finds his friends: The clownfish uses its ability to see ultraviolet light to find pals, identify enemies and look for food, new study claims).
Projektbezogene Publikationen (Auswahl)
- 2016. How Nemo sees its colourful world: variability of visual pigment genes (opsins) in anemomefish (Amphiprioninae). SMBE (Society for Molecular Biology and Evolution) Conference, Gold Coast, Australia
Stieb SM, Cortesi F, Dalton B, de Busserolles F, Chung WS, Carleton K, Justin Marshall JN
- 2019. A detailed investigation of the visual system and visual ecology of the Barrier Reef anemonefish, Amphiprion akindynos. Scientific Reports 9, 16459
Stieb SM, de Busserolles F, Carleton KL, Cortesi F, Chung W-S, Dalton B, Hammond LA, Marshall NJ
(Siehe online unter https://doi.org/10.1038/s41598-019-52297-0) - 2019. Seeing through the eyes of coral reef fish: how opsin setup and its topographic. Color Vision: Circuits and Behavior, Janelia Research Campus, USA
Stieb SM, de Busserolles F, Carleton K, Chung WS, Cortesi F, Dalton B, Feller A, Hammond L, Marshall JN, Seehausen O
