Bat bug Cimex pipistrelli transmission propensity in three bat species (Chiroptera: Vespertilionidae)

Bats, the only mammals capable of true flight, provide a unique opportunity to study the transmission of their ectoparasites. Transmission typically occurs intentionally and, if successful, can lead to new infestations. Bat bugs (Cimex pipistrelli) are seldom found on bats captured in mist nets, raising questions about their transmission by bats over long distances. Among the Palaearctic bat species, Nyctalus noctula was most frequently observed carrying bugs when mist-netted outside their roosts. Therefore, we aimed to investigate whether different bat species vary in the number of transmitted bugs. Previous research indicated that mated female cimicids, such as C. lectularius, tend to leave their colonies to initiate new infestations, which we hypothesized would also apply to bat bugs. To test our hypotheses, we used three bat species and examined both mated and virgin females to compare the number of bat bugs on bats emerging from bat boxes during aviary sessions. Our findings revealed that Myotis daubentonii had the fewest bat bugs, while Myotis myotis and Nyctalus noctula had significantly higher counts. Notably, N. noctula harboured more unfed bugs than M. myotis. In addition, the total number of mated females found on the body of N. noctula was higher than the number of virgin females, but the difference between the number of mated and virgin females per session was not significant. Our experiments indicate that bat bugs preferentially disperse on larger bats, and that they feed for longer durations on N. noctula compared to M. myotis, making N. noctula a more effective vector for bat bugs.