| Popis: |
In their natural environment, some Brachyura from the shallow water infralittoral zone use several camouflage techniques, and many kinds of objects, to conceal their presence on the substratum. In this study we offered to different species of Mediterranean Brachyura a wide choice of materials to be used for their camouflaging, in order to verify weather, in any of the species considered, there is the tendency to make a precise choice among the objects left at their disposal. We observed individuals of Brachyura in an aquarium. The crabs had several types of objects at their disposal, either of a biological (animals, animal remains, plants) or non-biological origin (grains of sand and plastic materials), that we had previously obtained during open sea dives or removed from specimens caught in traps. We noticed that the tested animals exhibited a clear tendency in their choice of objects. Their choice was related to substantial differences in the morphology and bio-mechanics of the limbs used for catching and holding objects. Differences in superficial structures on other parts of the exoskeleton, such as hooks, bristles and bumps, also influenced the choice. Finally, the choice of some particular camouflaging materials can also be related to the characteristics of the habitat of the species, both for biotic or abiotic factors. |
