La alimentación y el sustrato en los opistobranquios ibéricos

Food and substrate in Iberian Opisthobranchs. — In this paper some new and miscellaneous data on food and substrate of Iberian Opisthobranchs are presented, together with some comments on feeding behaviour, and a classification of the species according to their food. The groupings so formed reflect taxonomy and functional morphology: the Cephalaspidea are mainly sedimentivores and microcarnivores, the Sacoglossa algae-suckers, the Aplysiacea macroherbivores, the Pleurobranchacea suckers or browsers on ascidians and sponges, the Doridacea browsers or suckers on sessile invertebrates, mainly ascidians, polyzoans and sponges, the Dendronotacea browsers on cnidarians, macrophagous or parasites, and the Eolidacea feed also on cnidarians and, less often, on eggs andother opisthobranchs (tables 1, 2 and 3). In relation to substrate, the Tectibranchs are mainly soft-bottoms-dwelling animáis, and the Nudibranchs mainly inhabitants of hard-bottoms (table 4). Euryphagy and stenophagy are considered as partial aspects of a broader set of ecological characteristics of these molluscs, that can be discussed also in terms of the two different ecological strategies (r and K). Life span, number of generations per year, wastage of the prey in the individual opisthobranch, and abundance, diversity and competition in their populations are related with these strategies. A closing appendix
restricts the concept of symbiosis in Opisthobranchs to the sacoglossan-chloroplast and cleaning associations.