Patterns of cryptic host specificity in duck lice based on molecular data

Abstract

Documenting patterns of host specificity in parasites relies on the adequate definition of parasite species. In many cases, parasites have simplified morphology, making species delimitation based on traditional morphological characters difficult. Molecular data can help in assessing whether widespread parasites harbour cryptic species and, alternatively, in guiding further taxonomic revision in cases in which there is morphological variation. The duck louse genus Anaticola (Phthiraptera: Philopteridae), based on current taxonomy, contains both host-specific and widespread species. Mitochondrial and nuclear DNA sequences of samples from this genus were used to document patterns of host specificity. The comparison of these patterns with morphological variations in Anaticola revealed a general correspondence between the groups identified by DNA sequences and morphology, respectively. These results suggest that a more thorough taxonomic review of this genus is needed. In general, the groups identified on the basis of molecular data were associated with particular groups of waterfowl (e.g. dabbling ducks, sea ducks, geese) or specific biogeographic regions (e.g. North America, South America, Australia, Eurasia).

Molecular phylogeny and novel host associations of avian chewing lice (Insecta: Phthiraptera) from South Africa

“…As many louse specimens in our samples represent undescribed species (Table S1), the 105 new host associations comprise a minimum estimate based on the assumption that all lice belonging to the same genus and parasitizing the same host species represent the same species. It is possible that multiple congeneric species of lice may exist on a single host species (Price et al ., ), especially given that previous studies have shown that different host populations can show high levels of genetic differentiation in their respective lice, resulting in the discovery of cryptic lineages (Voelker et al ., ; Escalante et al ., ). For instance, our Brueelia specimens from Plocepasser mahali mahali represent a different species than material from the same host species (subspecies P. mahali melanorhynchus ) we have seen from Ethiopia (D. Gustafsson, personal observation).…”

“…Furthermore, studies using molecular phylogenetics to explore louse diversity in this region are lacking (Sychra et al ., ). Molecular studies exploring parasite diversity are necessary because lice have been shown to exhibit cryptic speciation, and it is often impossible to tell closely related species apart solely based on morphological traits (Escalante et al ., ); African lice are no exception. The importance of molecular studies to identify African louse lineages has been highlighted in recent studies based on lice from the Democratic Republic of the Congo (Light et al ., ) and Benin (Takano et al ., ).…”

The ectoparasites of hybrid ducks in New Zealand (Mallard x Grey Duck)

“…In birds, feather lice predominantly show vertical transmission from parents to offspring, during brooding and feeding of chicks ( Clayton et al, 2016 ). However, the chewing lice parasitising ducks, geese and swans (Aves: Anseriformes) around the world are among the least specific of all avian lice ( Escalante et al, 2016 ). Whether these parasites are generalists because of the recent radiation of their hosts, because of their hosts’ behaviour and ecology or because of the biology of the lice (i.e., increased dispersal capabilities) is still unknown.…”

Cophylogenetic analysis of lice in theColpocephalumcomplex (Phthiraptera: Amblycera)

“…Similarly, in a recent study of duck lice by Escalante et al. () clades of lice with virtually no COI genetic divergence were found on host taxa across a wide geographic distribution.…”

“…Escalante et al. () also found clades of closely related (and morphologically similar) lice occurring on distantly related duck hosts. We also sampled other Colpocephalum complex subgenera from geographically widespread localities (e.g., lice from Buteo jamaicensis ), and these were morphologically and genetically identical.…”