Lagarde R., Borie G., Blob R. W., Schoenfuss H. L., Ponton Dominique. (2018). Intra- and inter-specific morphological diversity of amphidromous gobies influences waterfall-climbing performance. Journal of Zoology, 306 (4), p. 243-251. ISSN 0952-8369.
Titre du document
Intra- and inter-specific morphological diversity of amphidromous gobies influences waterfall-climbing performance
Lagarde R., Borie G., Blob R. W., Schoenfuss H. L., Ponton Dominique
Source
Journal of Zoology, 2018,
306 (4), p. 243-251 ISSN 0952-8369
The morphology of an individual can affect functional performance and, ultimately, survival and fitness. To study these links, a first step is to evaluate the relationship between morphology and performance. Sicydiine fishes are an interesting model for such studies, because successful completion of their life cycle depends on a functionally demanding task: climbing waterfalls when they return to freshwater from the ocean. Previous studies identified two different climbing modes among sicydiines: 'inching' and 'powerburst'. Relationships between morphology and climbing performance have been found for inching and powerburst species present on different islands from distant oceans (Pacific and Caribbean), but species from the same island have not been compared. In this study, we challenged two different sicydiine species from Reunion Island to an artificial climbing ramp: the inching climber Sicyopterus lagocephalus and the powerburst climber Cotylopus acutipinnis. For each species, we evaluated differences in morphology between successful and unsuccessful climbers. We predicted that species with similar climbing styles (S. lagocephalus and S. stimpsoni) would show differences between successful and unsuccessful climbers that more closely resembled each other than differences between successful and unsuccessful climbers across species from the same island (S. lagocephalus and C. acutipinnis). This prediction was only partially met. S. lagocephalus individuals with a streamlined body showed better climbing performance, as observed for S. stimpsoni. However, the size of the pelvic sucker, which fish use to attach to the substrate while resting, appeared less important for S. lagocephalus than for S. stimpsoni and C. acutipinnis. Instead, the size of the mouth, which inching species use to attach to the substrate while moving up, seemed important for S. lagocephalus but not for other species. Thus, differences in the morphology-performance relationship among sicydiines may relate not only to differences in climbing mode, but also to species-specific specializations within each climbing mode.
