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OCR
§ The limits of animal communities. The concept of supersocion | 93 of catenae and, also, of catenaria, whose limits are semaphoronts that provide energy for the presocium. The presocium, therefore, meets catenae and catenaria on a broad front; it does not include them but is built on them, and is above them. There are many populations occupying the same space, but their needs are drastically different; it is impossible to lump them into one group. A red deer lives where the winter moth, the stag beetle and thousands of other populations are also present, yet they have very little to do with each other, apart from occupying the same location. How can we recognise the frames of an association among these populations, with manifold life histories, and sharply different sizes and feeding habits? This thorny question of categorisation can be only solved by focusing on energy sources, because this is the sole factor that determines the size and boundaries of the association, and which organises them into such communities. It has been established that the ultimate energy source is the vegetation, and we saw that this is present in stands of different biotopic value. From the structural point of view of the catenaria, it is indifferent whether these energy sources originate from a single oecus, a sub-biotope, or one or more biotopes. Accordingly, however, communities of very different sizes can be formed. A catena rooted in poppies, an oilseed rape plant or an oak tree is spatially more fixed than a presocium, to which elaterid and melolonthid beetle larvae belong. If, however, we classified all zoocoenoses as presocia, whose energy source extends beyond a single oecus, then the mole, the field vole, soil-living mites, the winter moth, tits, grasshoppers, roe deer and the common viper would all belong to one group, this is a clear nonsense; if we did this, we would be classifying the set of animals living in a given space as a zoocoenosis. The most striking feature is the size differences: the deer, grazing on the meadow, and the leafhopper, sucking on the plants of the meadow, would belong in one group. The former appropriates quite a share of the available energy source, while the latter would hardly need much. Based on the details articulated previously about the associations and their boundaries, the associative boundaries of these co-occurring populations can be recognised. The catena and catenarium, as they are built on a single oecus, can only include animals of small size, from arthropods and molluscs downwards. The members of the presocium are also of small size, with the only difference being the wider relationship of these populations to the plant-based energy sources. Sometimes, the space occupied by a single population of a given presocium is surprisingly big; for example, the bees (Apoidea) range very much farther, relative to their size, than the field voles do. The latter, however, belong to a different, wider associative category. Evolutionary considerations justify that we consider another factor in the categorisation of animal
