Ectoparasites of the Brown and Black bears of Japan (II)

Abstract

A survey of ectoparasitic species recovered a total of 148 wild Ursus arctos and 21 wild Ursus thibetanus yielded the following results- New ectoparasitic species : Ixodes nipponensis was newly discovered on U. arctos while I. persulcatus was recovered for the first time from U. thibetanus. Furthermore, it was determined that both species are commonly parasitic on U. arctos and U. thibetanus. Dynamics of parasitic seasonality : Each of the five species of Ixodidae found on U. arctos in Hokkaido displayed characteristic features with regard to parasitic Seasonality. One common factor was that they all displayed lowest prevalence in both March and August. Within the Ixodidae, only Haemaphysalis japonica seemed to be parasitic for the whole year. H. megaspinosa was parasitic in all months except March, H. flava in all months except March, August and September, I. ovatus in all months except January, March and December, and I. persulcatus in all months except January, August and December. Trichodectes pinguis appeared to be parasitic on both hosts, while Chaetopsylla tuberculaticeps was parasitic only on U. arctos the whole year round. Comparing gender, two species of Ixodes (I. ovatus and I. persulcatus) had a higher incidence in the female, with the exception of I. persulcatus in March. In contrast, three species of Haemaphysalis (H. japonica, H. flava and H. megaspinosa) as well as T. pinguis and C. tuberculaticeps had a higher incidence in the male with the exception of H. flava in the month of May. In particular, the three species of Haemaphysalis have a much higher incidence in the male in winter. Prevalence : Comparing prevalence of ectoparasitic species of Ixodidae, H. japonica had the highest prevalence in both hosts (56% in U. arctos, 76.1% in U. thibetanus). Next highest was I. ovatus in U. arctos (52%) and H. flava in U. thibetanus (57.1%), H. megaspinosa and I. persulcatus in U. arctos (29.7%) and I. ovatus in U. thibetanus (42.8%), H. flava in U. arctos (19.5%) and I. nipponensis in U. thibetanus (9.5%). Comparing prevalence of Ixodid ticks at the genus level, in U. arctos Haemaphysalis had 57.2% and Ixodes had 42.7%, while in U. thibetanus Haemaphysalis had a prevalence of 92.4% while Ixodes had only 7.6%. Highest prevalence for each species across the different habitat areas for U. arctos in Hokkaido were : both I. ovatus (90.9%) and H. flava (54.5%) in Oshima, all H. japonica (73.6%), H. megaspinosa (46%) and I. persulcatus (40.7%) in Yubari infestations in positive hosts was 64.3% in U. arctos and 68.4% in U. thibetanus. These prevalences showed higher values in U. thibetanus than U. arctos. In U. arctos mixed infestation was seen throughout all seasons except February and March. The maximum mixed infestation totalled five species. Prevalence of Ixodidae showed low values in high latitudinal areas compared with areas of low latitude. Addition : Please change page 63 and 67 of previous paper (門崎他 1990) "ВЩЦ" to "ВШИ".