Ecological studies on ixodid ticks : 2. Comparison of the seasonal occurrence of three ixodid ticks, Haemaphysalis flava, Ixodes ovatus and I. nipponensis in the south-western part of Saitama Prefecture

Abstract

The seasonal occurrence of three ixodid ticks, Haemaphysalis flava, Ixodes ovatus and I. nipponensis on wild animals and vegetations was investigated in the south-western part of Saitama Prefecture. Investigation on wild animals was made from 1976 through 1984,and on vegetations by flagging method from 1981 through 1983. 1. H. flava adults were collected on vegetations throughout the year, but the number decreased markedly in summer and slightly in winter. The nymphs showed similar trend to the adults with a large population throughout the year. The seasonal occurrence of the larvae showed an unimodality with a large peak in July to November. 2. The occurrence of I. ovatus adults on vegetations was common from spring to summer, whose pattern was characterized by the absence of autumn peak. The nymphs were seen on wild mice and moles from spring to autumn with a peak in April, and the larvae from autumn to spring with a peak in November. 3. I. nipponensis adults on vegetations were relatively abundant in June and July. Because of a small number of adults collected, its seasonal occurrence was indistinct. The nymphs on vegetations were abundant in March to August, but scarce in September to February. The parasitic activity pattern of the nymphs on lizards was similar to that on vegetations. The larvae on vegetations showed an unimodality with a large peak in July to October, but those on lizards were active from April to early December. 4. An outline of seasonal occurrence patterns of three ixodid ticks was pictured. The characteristics of seasonal occurrence of each ixodid tick were discussed in relation to environmental temperatures and diapause.