Relative abundance of rats and their ectoparasites in two grain warehouses in Calcutta, India, during 1964-1965.

Abstract

Rodents were trapped in 2 grain warehouses in Calcutta, India, from October 1964 through October 1965 and their ectoparasites were collected. Trap successes of 85% and 57% in the 2 localities for more than 1100 trap nights in each area were indicative of very dense rodent populations. Bandicota bengalensis (G. & H.) constituted more than 94% of the rodents trapped in each area. Lesser numbers of Bandicota indica (Bechstein), Rattus norvegicus (Berkenhout), Rattus rattus (L.), and Mus musculus L. were collected. Four species of ectoparasites were found commonly on B. bengalensis, i.e., Laelaps nuttalli Hirst, Polyplax spinulosa (Burmeister), Xenopsylla astia Roths., and Xenopsylla cheopis (Roths.). Prevalence and relative abundance data are presented. L. nuttalli populations fluctuated irregularly at each site. P. spinulosa was most prevalent during the relatively cool winter months as were both species of fleas. X. astia was more abundant and more prevalent on B. bengalensis than was X. cheopis. The possible significance of temporal changes in the flea populations and the apparent preference of X. astia for B. bengalensis are discussed with reference to the epidemiology of plague in Calcutta.