Mechanical defensive adaptations of three Mediterranean sea urchin species
| Autor: | Konstantinos Voulgaris, Anastasios Varkoulis, Stefanos Zaoutsos, Antonios Stratakis, Dimitris Vafidis |
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| Jazyk: | angličtina |
| Předmět: |
Ecology
Invasive species Mechanical properties mechanical properties Mineralogy ecological adaptations invasive species Mediterranean sea sea urchins Ecological adaptations mineralogy Sea urchins Ecology Evolution Behavior and Systematics Research Articles QH540-549.5 Nature and Landscape Conservation Research Article |
| Zdroj: | Ecology and Evolution, Vol 11, Iss 24, Pp 17734-17743 (2021) Ecology and Evolution |
| Popis: | In the Mediterranean, Paracentrotus lividus and Sphaerechinus granularis are important drivers of benthic ecosystems, often coexisting in sublittoral communities. However, the introduction of the invasive diadematoid Diadema setosum, which utilizes venomous spines, may affect these communities. To describe the mechanical properties of the test and spines of these three species, specimens were collected in winter of 2019 from the sublittoral zone of the Dodecanese island complex, southeastern Aegean Sea. This region serves as a gateway for invasive species to the Mediterranean Sea. Crushing test was conducted on live individuals, while 3‐point bending test was used to estimate spine stiffness. Porosity and mineralogy of the test and spine, thickness of the test, and breaking length of the spine were measured and compared, while the microstructural architecture was also determined. The test of S. granularis was the most robust (194.35 ± 59.59 N), while the spines of D. setosum (4.76 ± 2.13 GPa) exhibited highest flexibility. Increased porosity and thickness of the test were related to increased robustness, whereas increased flexibility of the spine was attributed to high porosity, indicating that porosity in the skeleton plays a key role in preventing fracture. The spines of S. granularis exhibited highest length after fracture % (71.54 ± 5.5%). D. setosum exhibited higher values of Mg concentration in the test (10%) compared with the spines (4%). For the first time, the mineralogy of an invasive species is compared with its native counterpart, while a comparison of the mechanical properties of different species of the same ecosystem also takes place. This study highlights different ways, in which sea urchins utilize their skeleton and showcases the ecological significance of these adaptations, one of which is the different ways of utilization of the skeleton for defensive purposes, while the other is the ability of D. setosum to decrease the Mg % of its skeleton degrading its mechanical properties, without compromising its defense, by depending on venomous bearing spines. This enables this species to occupy not only tropical habitats, where it is indigenous, but also temperate like the eastern Mediterranean, which it has recently invaded. The present work describes various defensive mechanical adaptations of a venomous invasive sea urchin species and two indigenous Mediterranean species. Furthermore, it focuses on the functional aspects of the skeleton (test, spines), revealing important differentiations among all three species, not only regarding defensive mechanisms, but also other ecological adaptations. |
| Databáze: | OpenAIRE |
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