Restricted Geographic Sampling Yields Low Parasitism Rates but Surprisingly Diverse Host Associations in Avian Lice (Insecta: Phthiraptera) from South Texas

Abstract

South Texas is a highly variable region encompassing multiple habitat types and harboring a wide diversity of organisms. However, the parasite fauna in this region is poorly known, especially for avian ectoparasites such as lice. To better understand avian louse diversity and host associations in South Texas, we examined a total of 507 birds for chewing lice. Lice were morphologically identified to genus and phylogenetic analysis was performed using one mitochondrial (COI) and two nuclear (18S rRNA and EF-1α) genes. Of the birds examined, 69 (13.5%) were parasitized by lice resulting in a total of 63 host associations across 45 bird species, 29 of which were previously unrecorded. The predominant taxa encountered during this study included two of the most diverse louse genera, Myrsidea and Brueelia. Molecular analyses revealed 21 distinct genetic lineages, 17 of which are associated with novel host associations and may represent new species. This study represents the first extensive examination of avian louse host associations and relationships in Texas and reveals that there is still much to be learned about ectoparasite diversity in the New World.

Prevalence and diversity of parasitic bird lice (Insecta: Psocodea) in northeast Arkansas

“…Birds collected from AR had a slightly lower louse prevalence (7.31%) compared to the louse prevalence of all birds sampled (10.57%). The overall prevalence from our study is comparable to the numbers reported from Texas in a 2021 study across different host taxa (13.5%) ( Pistone et al, 2021 ). The decreased prevalence in our study could be related to possible differences in habitat or climate, such as humidity.…”

“…This number of unreported relationships was not surprising due to the lack of research on diversity of bird lice in the southeastern U.S. These novel associations were most commonly found among abundant and well-researched birds such as Passerellidae and Parulidae, which have relatively underreported ectoparasitic data ( Price et al, 2003 ; Bush et al, 2016 ; Pistone et al, 2021 ). In most cases the associations were not completely unexpected because of similar lice associated with related host species ( Price et al, 2003 ).…”

“…Because lice acquire water from the atmosphere, they often have a higher abundance in humid climates ( Carrillo et al, 2007 ). For example, a study of bird lice from drier regions in Texas found approximately 13% prevalence across different bird species ( Pistone et al, 2021 ), whereas Neotropical birds often have more than 50% prevalence ( Clayton et al, 1992 ; Clayton and Walther, 2001 ). Prevalence is also shaped by host phenology and behavior such as mating and brooding seasons ( Sychra et al, 2011 ).…”

“…Despite the considerable body of research on bird lice, patterns of prevalence and diversity of lice remain unknown for many host groups and geographic regions ( Bush, 2004 ; Carrillo et al, 2007 ; Bush et al, 2009 ; Durkin et al, 2015 ; Gustafsson and Bush, 2020 ; Pistone et al, 2021 ). These patterns are overlooked in part due to the obscure lifestyles and cryptic morphology of lice.…”

“…The southeast region of the United States, and particularly the state of Arkansas, is one region that has relatively few studies focused on ectosymbionts of birds ( Hood and Welch, 1980 ; McAllister et al, 2019 ). There have been several surveys of ectoparasites from particular species or group of birds from the region, but no studies have compared prevalence and genetic patterns across broader taxonomic samples ( Edgar, 1953 ; Bush et al, 2009 ; Garbarino et al, 2013 ; Pistone et al, 2021 ).…”