Seite 86 [86]
OCR
84 | IV. Categories of animal associations and the Toxopteraetena graminum catena is also independent of the other three. The four catenae can develop independently of each other, without their respective pre-existence. Their coexistence will remain undisturbed, unless one of the corrumpents overexploits the plant energy source. (Due to this, all of them belong to a next - more extensive — associative frame) The formation of the catenae starting from plant-feeding intercalary elements can be a consequence of plant mortality caused by the activity of corrumpent elements. Thus, an Aspidiotitena perniciosi catena can be followed by an Eccoptogastritena rugulosi catena. Several authors have attempted the delineation of the smallest frames of zoocoenoses. The critical comments about the terms faunula, synusium, choriocoenosis, merocoenosis were presented earlier; given that all these are ecofaunistical terms, they cannot be used in an approach that considers the trophic chains as the backbone of zoocoenoses. Friederichs (1930) correctly noticed that animals linked to a certain plant have an associative position, but the term suggested by him, association, cannot be used without causing confusion, because of its pre-existing use in plant sociology. This type of zoocoenosis will be discussed in the next chapter. The catena has a wider interpretation as well. Although we should consider the communities based on a monophagous herbivore as characteristic catenae, communities formed around polyphages can just as easily be identified, and these - as we shall see on p. 122 - will form a presocium. Leaving aside the presocium, and restricting our study to such a community (for example, the parasitoids and predators of Lymantria dispar), and especially ifthe corrumpent is monophagous at a given place and time - in this example, on oak trees we can consider this as a pure catena, and express this in its nomenclature, too. One condition, however, must always be met: a zoocoenosis has always to be identified as a trophic chain that starts from a plant. While taking this approach, zoocoenology can use methods that try to describe populations through their spatial distribution (e.g. quadrat, plant or plant part) but these populations cannot be seen as zoocoenological categories, as that would be an ecofaunistical perspective. From the terms found in the literature, the connex (Friederichs, 1930) is the closest to that of the catena, and we could have adopted this, if only the author had not expanded its boundaries to such an extent (as in the Anthonomus grandis connex example) that it far exceeds the acceptability for a zoocoenological category. The term connex has continued to develop in the direction marked by Friederichs (Franz, 1950; Tischler, 1950, 1951) and, currently, it means a system of dependences from the plant through symbionts and parasitism, and the abiotic conditions of the biotope (“Abhagengingkeitsbeziehungen’, Tischler, 1951) that creates a community out of a biocoenosis. The connex is, therefore, the organisational skeleton of a community of living beings. Schwenke (1953), disputing Tischler’s (1951) idea, correctly states that, in such schemes, there is always an abstraction
