REGENERATION OF HALLER SENSORY ORGAN IN THE TICK, IXODES-RUBICUNDUS (ACARI, IXODIDAE)

A study of regeneration in nymphs and adults of the South African tick Ixodes (Afrixodes) rubicundus, from which the forelegs had been amput ated during the previous instar, revealed that the structural changes in regenerated Haller's sensory organs resemble those observed in othe r ixodid ticks, in particular in another prostriate tick, Ixodes (Ixod es) ricinus. The adult regenerates re-establish their atavistic featur es in terms of the increased number of different sensilla on the dista l knell, in the anterior pit and the capsule. The nymphal regenerates, in contrast, re-establish the features of the previous instar through a reduction in the number of some sensilla on the distal knell and in the post-capsular area. The structural changes in different compartme nts of the organ appear independent. The phenomenon of regenerative in duction through the appearance of specific changes in Haller's organ o f the contralateral non-treated foreleg is probably characteristic onl y of prostriate ticks. A unique modification in the regenerated Haller 's organ as revealed by duplication of the Haller's organ capsule was discovered in both I. rubicundus nymphs and adult ticks.