LIMB REGENERATION IN IXODID TICKS

Experiments with three species of ixodid ticks have demonstrated that an effect of limb amputation in engorged nymphs depends on the time of operation. Engorged nymphs are capable of complete limb regeneration with restoring their structural elements (especially the Haller's orga n on tarsi of forelegs) only before apolysis, during the active crawli ng state in Haemaphysalis longicornis and Hyalomma asiaticum, or durin g morphogenetic diapause in Ixodes ricinus. The restoration of amputat ed legs takes place after nymphs moult to adults. Limb amputation afte r the beginning of apolysis results in the formation of ugly and defec tive regenerates or in their miniaturization (sometimes amputated legs are absent completely). Limb amputation just before ecdysis either ha s no effect at all or results in a stump formation on tarsi or tibia o f amputated legs.