Hosts and Life Cycle of Ixodes ceylonensis Kohls, 1950, with Descriptions of Its Male, Nymph, and Larva

Abstract

Host records of Ixodes ceylonensis Kohls, 1950 in Shimoga District, Mysore State, India, based on extensive collections during 1963-64, are given. This tick is an ectoparasite of several species of small mammals, with the immature stages showing a predilection for the shrew, Suncus murinus. The life cycle of the species as worked out in the laboratory is detailed. The hitherto unknown male and immature stages of this species are illustrated and described. Ixodes ceylonensis was described by Kohls (1950) from two females, one from a mongoose, Herpestes smithii zeylanicus Thomas, and the other from Rattus rattus kandianus Kelaart, in Namumkula, Uva Province, Ceylon. Since 1957 host records concerning a limited number of females of this species and, recently, extensive numbers of the immature stages have been accumulated in India during studies on the epidemiology of Kyasanur Forest disease (KFD) in Sagar, Shimoga District, Mysore State. (This area has been described by Work, 1958 and by Trapido et al., 1964.) In addition, moderate numbers of I. ceylonensis have been collected from ground drags in the forest during the monsoon season. Laboratory rearing was accomplished in September 1963, and it then became possible for the first time to differentiate the immature stages from those of I. petauristae Warburton, 1933, which also occurs commonly in the study area. Thus far, no males of I. ceylonensis have been taken on any host in this area. The present paper reports the host relationships and seasonal prevalence of I. ceylonensis in the Sagar area, gives details of the life cycle of the species as worked out in the laboratory, and describes and illustrates the hitherto unknown male, nymph, and larva.