Behavioral areas in black flies (Simuliidae, Diptera) on the host from approach to take-up of blood. A contribution to quantitative recording in active sub-populations

The continual process of approach, landing and take-up of blood in black flies on and upon the host resp., is structured into separate behavioral areas which are specified according to conceptual groups (eg. density and activity of approach, landing activity). Among these areas there is a hierarchy of sub-populations, the formal relationships of which are determined. There are numerous and non-homogenous environmental factors interfering the behavioral areas to a different extent and influencing distinct sequences as well as the entire procedure of behavioral activities. Thus, a stable numeric relation among the active sub-populations following each other hierarchically can be expected by no means. The number of landing black flies will never match the number of the ones taking up blood. Superordinate sub-populations or population size cannot be readily approached recording simply sub-populations of certain activities and vice versa. Particularly, it is examined up to which extent sub-populations can be recorded within the behavioral areas methodically. Using bibliographical references it is discussed, what several authors really did record in man and animal, and how far these recordings are comparable under different conceptual conditions. The meaningfulness of some recording parameters is discussed in relation to a concrete question or target, resp. The influence of environmental factors, chiefly on water balance in black flies, which is coinfluenced by vapour pressure of water and its gradients to a large extent, should be applied to behavioral areas. Thus, induction of increase in approach- and biting activities causing harm, i. e. the damage as a matter of fact, can be easier understood. Probably, warnings about losses to come about during the main suffering period, when the cattle is put out to pasture the first time in spring, could be stated more precisely