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OCR
§ Ouantitative characteristics | 141 secondary (hyper)parasite. The degree of obstancy of the latter will have to be related to the primary parasite, because its impact is on this, rather than the corrumpent host of the primary parasitoid. To obtain the degree of obstancy of episitic populations is much more difficult, because their activity does not leave recognisable traces on which we can assess their impact on their prey. Their role is a good illustration of the dynamism of the zoocoenosis, and that this dynamism is played out in time, rather than space. The degree of obstancy of episitic populations can be established by observation, because only laboratory studies will provide information of theoretical value, and these are difficult to use when we want to assess another zoocoenosis. Prey consumption depends on many factors, and the precise degree of obstancy realised by an episitic population in a community can only be registered through observations over a longer period. Based on these arguments, the relationship between dominance and zoocoenological role is as follows. Given that, in every catena, the corrumpents have to be the majority, this population can only be the dominant element because, if the combined dominance of the obstants threaten the existence of the catena, then the whole zoocoenosis formed around it would, inevitably, fall apart. In both the catenarium and the presocium, there are several corrumpent elements, of which one is dominant, or more than one are co-dominants. The decisive role in a zoocoenosis will be reflected not through dominance by numbers, nor by body mass, but by the degree of corrumpency. In the case of co-dominance, this is to be judged by the transformative effect exerted on the energy source of the studied population, without considering its aspect position. The same applies when judging obstant elements: their importance is assessed based on thedegree of obstancy, and not by dominance. This allows the proper assessment of the role of an episitic syntrophium, which has a high degree of obstancy but its dominance lags behind the others - yet it can have the biggest influence on the coenosis. Due to the presence of endoparasitoids, we face a peculiar situation, namely that, at a certain stage of the coenosis, the number of individuals surveyed does not match reality. This becomes understandable if we realise that, in such cases, two populations occupy the same space because, within one semaphoront group, another one is hidden. The host is still alive, and the parasite developing inside it is also alive. The 400 caterpillars are 560 semaphoronts, because in 160 caterpillars, there is a larva of a tachinid parasitoid. At the end, we will see 240 butterflies and 160 tachinid flies, which equals the starting number; but, it is also possible that the final number will be considerably higher because, out of 160 flies, 55 hosted gregarious secondary parasites, so, when they hatch, the number of individuals is even higher. In the evaluation of a supersocion, dominance is also diminished in importance. The relationships of this category to itself, and its environment, is much “wider” than we can express by numerical dominance values. We
