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86 | IV. Categories of animal associations and a host of obstant elements (Eupelmus [Eupelmella], Pteromalus [Habrocytus], Phaenecra). On the underside of the leaves, Doralitena fabae appear and are active until mid-summer, bringing several obstant elements into the poppy field (Syrphus, Chrysopa, Aphidius, Coccinella, Pachyneuron, Coruna [Pachycrepis] etc.). In the bud stage, we find the Ceutorrhynchitena maculae-albae, followed by Dasyneuraetena papaveris; both are sources of a rich trophic chain (Bracon, Chelonus [Chelonella], Tetrastichus, Eurytoma, Pediobius [Rhopalotus], etc.). All these catenae, for the reason of a shared energy source, necessarily belong together, and will form a bigger unit of animal association, here named the catenarium, a chain of catenae. The catenae of the catenarium are kept together by the common food plant that also anchors them, even if temporarily, in an oecus. In this way, a quality energy source will keep together animal associations that are characteristic, at least to a certain degree. The catenae of the catenarium do not have as strong interrelationships as the members of an individual catena, because between them, apart from the common energy source and eventual multi-catenal obstant and intercalary populations, they have scarcely any horizontal link. Without doubt, such catenaria exist. The catenae of the poppy field listed above are entirely different than the population groups of Oscinellaetena frit, Chloropiditena pumilionis and Cephitena pygmaei living in a wheat field. The catenaria of an oecus composed of oak or beech trees will be sharply different, as will be the catenaria of rose or hazelnut bushes. Although the catenae forming a catenarium are independent, there is no doubt that their living side-by-side will, inevitably, stimulate interactions that will influence their development, population dynamics, and trophic needs. The interrelationships that are a criterion of all animal associations, therefore, doubtlessly exist in the catenarium. The intercalary elements living on animal debris will not join a single catena in such high numbers compared to a catenarium where there is much more debris, and of more varied quality. The activity of corrumpent elements can cause the death of plant parts, allowing the assimilation of syrmatophagous elements. The sustinents, by their nature, are temporary elements of any catenarium where the food plant requires insect pollination. The possible insertion of corrumpent elements that live on seeds or fruit also depends on their activity, as well as of the relevant catenae, but all these can be blocked by the activity of corrumpents specialised on flower buds. Ifthe Contarinia medicaginis uses the flower buds of the lucerne, the sustinents will be absent from the oecus, and neither the Tychiitena flavi nor the Bruchopagitena gibbi can develop there. A single catena within a catenarium can, therefore, influence the density of certain population groups in the same way as within a catena; a given trophic level can influence the one below or above it. The catenarium will directly connect with the plant cover in all directions (through all catenae). A carcass therefore cannot be a catenarium, whose
