[Morphofunctional changes in the midgut of the Ixodes females (Acari: Ixodidae) during the immunizing feedings].

The changes of the midgut in the females of the tick species Ixodes persulcatus and I. ricinus during the second and third immunizing feeding on rabbits were studied by the histological technics. The alternation of one generation of the digestive cells of nymphal stage and two generations of the digestive cells of adult stage was observed. The generation of secretory cells is absent. The tick completes feeding and drop off when the last generation of the digestive cells is on the initial activity stages. The amount of the blood consumed is not enough for the rhythmical functioning of the midgut. The feeding of tick is broken on the second phase and full satiation does not take place. It is apparently an effect of the interruption of the blood entrance into the midgut cavity of feeding tick as a probable result of anti-ticks resistance of unnatural hosts.