ECTOPARASITES OF CHIROPTERAN SPECIES IN THE MANNAR ISLAND AND POONERYN REGION OF SRI LANKA

Abstract

Bats are hosts to a variety of ectoparasites, which may impact their health and the transmission of zoonotic pathogens. However, studies on bat parasites in Sri Lanka are very limited and are mainly restricted to the bats in the wet zone. Therefore, the overall objective of this study was to examine the prevalence, diversity and distribution of ectoparasites associated with selected bat species from the Mannar Island and Pooneryn area of the Northern Province of Sri Lanka. A total of 246 bats were captured using mist nets at dawn and dusk. All captures and handling were permitted by the Department of Wildlife and Conservation, Sri Lanka (WL/3/2/30/2024). Ectoparasites were collected from the captured live bats and preserved in 70% ethanol. Morphological identification of parasites was carried out using published taxonomic keys and guides. Parameters such as parasite prevalence, abundance, mean intensity, Shannon-Weiner diversity index and average parasitic load per host species were calculated. Ectoparasites were found in all five species of bats surveyed. Scotophilus kuhlii had ectoparasites in 23 (21.9%) of them, while Cynopterus sphinx had ectoparasites only in 2 (3.85 %) of them. A single infection was observed in C. sphinx, Scotophilus heathi (0.09%), Pipistrellus coromandra (2.94%) and Taphozous longimanus (25%) bat species while, multiple infections were seen in S. kuhlii. Bat flies from family Nycteribiidae, a mite species from family Spinturnicidae and a hard tick from family Ixodidae were found among a total of 183 ectoparasites. The dominance of Nycteribia species, including three Nycteribia fly species and five other unidentified species from the family was noted. Although parasites in S. kuhlii showed the highest diversity (H’=1.77) and parasitic load (175), collectively parasitic loads did not show a significant difference (one way ANOVA, p>0.05) within the five-host species from a single study region or between the two regions: Mannar Islands and Pooneryn. S. kuhlii harbor larger numbers of ectoparasites and experience higher frequency of infections as they live in colonies as opposed to other host species sampled. This study suggests that roosting behavior may contribute to differences in patterns of host-parasite associations, while regional factors (arid vs. dry regions) may not. The present study further contributes to bridge the knowledge gap on host parasite associations in bats of arid and dry zones in Sri Lanka, as the first such scientific attempt.