Grooming is an important behaviour for the control of ectoparasites in mammals but it is also energetically costly. Therefore, the time an animal allocates to grooming may be used to evaluate the potential cost of an ectoparasite to its host. Most mammals are host to more than one ectoparasite species, which may impose different costs. We experimentally evaluated the relative cost of three ectoparasite species by observing the grooming response of their host, Gould's wattled bat (Chalinolobus gouldii), to the manipulation of parasite load. The parasite that spent its entire lifecycle on the host, the mite Spinturnix novaehollandiae, triggered the greatest increase in grooming. A grooming response was not as evident for the other parasites (a smaller mite, Trichonyssus womersleyi, and a bat fly, Basilia troughtoni), possibly because part of their lifecycle occurred in the roost, which the host may avoid by discriminative roost selection. Grooming behaviour, although not significantly altered by parasites other than S. novaehollandiae, was performed by most bats, which maintained a baseline grooming rate even when relatively parasite free. This study suggests heterogeneity in the costs imparted on a host by members of its ectoparasite community and the potential importance of considering parasite life-history when evaluating the influence of parasites on the host.