Experimental study of the seasonal adaptation of the ticks Haemaphysalis concinna Koch. from various regions of the Fast East
Belozerov, V.N.
Meditsinskaia Parazitologiia i Parazitarnye Bolezni 43(1): 31-38
1974
ISSN/ISBN: 0025-8326 PMID: 4477632 Document Number: 82646
The progeny of females of Haemaphysalis concinna Koch collected in 1970 from Khabarovsk, Iman and the coastal village of Sidim in the Soviet Far East were reared in various photoperiods at 18 and 25 deg C in Leningrad. Photoperiod was found to have generally similar effects on the feeding behaviour and development rates of larvae, nymphs and adults originating from all three places. In contrast to short-day conditions (12-14 h light daily), long-day conditions (16-20 h) stimulated the attachment and feeding of all stages, increased the rate of development of larvae and nymphs and reduced the incidence of diapause in nymphs. However, ticks originating from Sidim, the most southerly point, showed small but important differences in response from the ticks from the other places. After 2-3 months in short-day conditions, 26% of the Sidim larvae attached and fed when placed on mice, as compared with 8-9% of the other larvae. After 4 months in long-day conditions, 75% of the Sidim nymphs attached and fed, as compared with 40-48% of the others. The threshold photoperiod for the change from a long-day to a short-day response was about 15 h for the Khabarovsk nymphs and about 1 h shorter for the Sidim nymphs. These differences are regarded as adaptations that serve to synchronise the seasonal cycle of H. concinna on the coast and in inland areas with the respective climatic conditions.