Abstract:
Background: The recognition and delineation of morphologically indistinguishable cryptic species can have broad
implications for wildlife conservation, disease ecology and accurate estimates of biodiversity. Parasites are intriguing
in the study of cryptic speciation because unique evolutionary pressures and diversifying factors are generated by
ecological characteristics of host-parasite relationships, including host specifcity. Bat fies (Diptera: Nycteribiidae and
Streblidae) are obligate, hematophagous ectoparasites of bats that generally exhibit high host specifcity. One rare
exception is Penicillidia fulvida (Diptera: Nycteribiidae), an African bat fy found in association with many phylogenetically distant hosts. One explanation for P. fulvida’s extreme polyxeny is that it may represent a complex of host-specifc
yet cryptic species, an increasingly common fnding in molecular genetic studies of supposed generalist parasites.
Methods: A total of 65 P. fulvida specimens were collected at 14 localities across Kenya, from bat species representing
six bat families. Mitochondrial cytochrome c oxidase subunit 1 (COI) and nuclear 28S ribosomal RNA (rRNA) sequences
were obtained from 59 specimens and used to construct Bayesian and maximum likelihood phylogenies. Analysis of
molecular variance was used to determine how genetic variation in P. fulvida was allocated among host taxa.
Results: The 28S rRNA sequences studied were invariant within P. fulvida. Some genetic structure was present in the
COI sequence data, but this could be more parsimoniously explained by geography than host family.
Conclusions: Our results support the status of P. fulvida as a rare example of a single bat fy species with primary
host associations spanning multiple bat families. Gene fow among P. fulvida utilizing diferent host species may be
promoted by polyspecifc roosting behavior in bats, and host preference may also be malleable based on bat assemblages occupying shared roosts. The proclivity of generalist parasites to switch hosts makes them more likely to vector
or opportunistically transmit pathogens across host species boundaries. Consequently, the presence of polyxenous
bat fies is an important consideration to disease ecology as bat fies become increasingly known to be associated
with bat pathogens.
Keywords: Bat fies, Chiroptera, Ectoparasites, Kenya, Nycteribiidae, Host specifcity, Host-parasite interactions,
Cryptic species, Molecular biology
