@article {96177, title = {Mitochondrial genome of Geomydoecus aurei, a pocket-gopher louse}, journal = {PLoS One}, volume = {16}, year = {2021}, month = {Jul-27-2021}, pages = {13 pp}, type = {Open Access - Research article}, abstract = {

Parasitic lice demonstrate an unusual array of mitochondrial genome architectures and gene arrangements. We characterized the mitochondrial genome of Geomydoecus aurei, a chewing louse (Phthiraptera: Trichodectidae) found on pocket gophers (Rodentia: Geomyidae) using reads from both Illumina and Oxford Nanopore sequencing coupled with PCR, cloning, and Sanger sequencing to verify structure and arrangement for each chromosome. The genome consisted of 12 circular mitochondrial chromosomes ranging in size from 1,318 to 2,088 nucleotides (nt). Total genome size was 19,015 nt. All 37 genes typical of metazoans (2 rRNA genes, 22 tRNA genes, and 13 protein-coding genes) were present. An average of 26\% of each chromosome was composed of non-gene sequences. Within the non-gene region of each chromosome, there was a 79-nt nucleotide sequence that was identical among chromosomes and a conserved sequence with secondary structure that was always followed by a poly-T region. We hypothesize that these regions may be important in the initiation of transcription and DNA replication, respectively. The G. aurei genome shares 8 derived gene clusters with other chewing lice of mammals, but in G. aurei, genes on several chromosomes are not contiguous.

}, issn = {1932-6203}, doi = {10.1371/journal.pone.0254138}, url = {https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0254138}, author = {Theresa A. Spradling and Alexandra C. Place and Ashley L. Campbell and James W. Demastes} } @article {94866, title = {Temporal and spatial dynamics of competitive parapatry in chewing lice}, journal = {Ecology and Evolution}, volume = {9}, year = {2019}, month = {06-2019}, pages = {7410 - 7424}, abstract = {

Abstract: We synthesize observations from 1979 to 2016 of a contact zone involving two sub- species of pocket gophers (Thomomys bottae connectens and T. b. opulentus) and their respective chewing lice (Geomydoecus aurei and G. centralis) along the Río Grande Valley in New Mexico, U.S.A., to test predictions about the dynamics of the zone. Historically, the natural flood cycle of the Rio Grande prevented contact between the two subspecies of pocket gophers. Flood control measures completed in the 1930s permitted contact, thus establishing the hybrid zone between the pocket gophers and the contact zone between their lice (without hybridization). Since that time, the pocket gopher hybrid zone has stabilized, whereas the northern chewing louse spe- cies has replaced the southern louse species at a consistent rate of ~150 m/year. The 0.2\–0.8 width of the replacement zone has remained constant, reflecting the con- stant rate of chewing louse species turnover on a single gopher and within a local pocket gopher population. In contrast, the full width of the replacement zone (north- ernmost G. centralis to southernmost G. aurei) has increased annually. By employing a variety of metrics of the species replacement zone, we are better able to understand the dynamics of interactions between and among the chewing lice and their pocket gopher hosts. This research provides an opportunity to observe active species re- placement and resulting distributional shifts in a parasitic organism in its natural setting.

Data Availability Statement:: 1. Chewing louse microsatellite genotypes and R-scripts are available in Dryad, https://doi.org/10.5061/dryad.9sv4q00. 2. Parasite voucher specimens and frozen tissue samples from pocket gophers are stored at \−80\°C at the University of Northern Iowa and at Louisiana State University. 3. Pocket gopher voucher specimens are housed at the Louisiana State University Museum of Natural Science (LSUMZ), the Museum of Southwestern Biology, University of New Mexico (MSB), Museum of Vertebrate Zoology, University of California (MVZ), or the Biodiversity Research and Teaching Collections at Texas A\&M University (BRTC). 4. Current and future research directions of the team may be found at https://louselab.uni.edu/homepage.

}, keywords = {Chewing lice, contact zones, dispersal distance, hybrid zones, Pocket gophers, species replacement}, issn = {2045-7758}, doi = {10.1002/ece3.5183}, url = {https://onlinelibrary.wiley.com/toc/20457758/9/13}, author = {David J. Hafner and Mark S. Hafner and Theresa A. Spradling and Jessica E. Light and James W. Demastes} } @article {94578, title = {Development and Characterization of 12 Novel Polymorphic Microsatellite Loci for the Mammal Chewing Louse Geomydoecus aurei (Insecta: Phthiraptera) and a Comparison of Next-Generation Sequencing Approaches for Use in Parasitology}, journal = {Journal of Parasitology}, volume = {104}, year = {2018}, month = {02/2018}, pages = {89 - 95}, abstract = {

Next-generation sequencing methodologies open the door for evolutionary studies of wildlife parasites. We used 2 next-generation sequencing approaches to discover microsatellite loci in the pocket gopher chewing louse Geomydoecus aurei for use in population genetic studies. In one approach, we sequenced a library enriched for microsatellite loci; in the other approach, we mined microsatellites from genomic sequences. Following microsatellite discovery, promising loci were tested for amplification and polymorphism in 390 louse individuals from 13 pocket gopher hosts. In total, 12 loci were selected for analysis (6 from each methodology), none of which exhibited evidence of null alleles or heterozygote deficiencies. These 12 loci showed adequate genetic diversity for population-level analyses, with 3\–9 alleles per locus with an average HE per locus ranging from 0.32 to 0.70. Analysis of Molecular Variance (AMOVA) indicated that genetic variation among infrapopulations accounts for a low, but significant, percentage of the overall genetic variation, and individual louse infrapopulations showed FST values that were significantly different from zero in the majority of pairwise infrapopulation comparisons, despite all 13 infrapopulations being taken from the same locality. Therefore, these 12 polymorphic markers will be useful at the infrapopulation and population levels for future studies involving G. aurei. This study shows that next-generation sequencing methodologies can successfully be used to efficiently obtain data for a variety of evolutionary questions.

}, issn = {0022-3395}, doi = {10.1645/17-130}, url = {http://www.bioone.org/doi/10.1645/17-130}, author = {Jessica E. Light and Harper, Sheree E. and Kevin P. Johnson and James W. Demastes and Theresa A. Spradling} } @article {94572, title = {Loss of genetic diversity, recovery and allele surfing in a colonizing parasite, Geomydoecus aurei}, journal = {Molecular Ecology}, volume = {28}, year = {2019}, pages = {703 - 720}, abstract = {

Understanding the genetic consequences of changes in species distributions has wide-ranging implications for predicting future outcomes of climate change, for pro- tecting threatened or endangered populations and for understanding the history that has led to current genetic patterns within species. Herein, we examine the genetic consequences of range expansion over a 25-year period in a parasite (Geomydoecus aurei) that is in the process of expanding its geographic range via invasion of a novel host. By sampling the genetics of 1,935 G. aurei lice taken from 64 host individuals collected over this time period using 12 microsatellite markers, we test hypotheses concerning linear spatial expansion, genetic recovery time and allele surfing. We find evidence of decreasing allelic richness (AR) with increasing distance from the source population, supporting a linear, stepping stone model of spatial expansion that em- phasizes the effects of repeated bottleneck events during colonization. We provide evidence of post-bottleneck genetic recovery, with average AR of infrapopulations increasing about 30\% over the 225-generation span of time observed directly in this study. Our estimates of recovery rate suggest, however, that recovery has plateaued and that this population may not reach genetic diversity levels of the source popula- tion without further immigration from the source population. Finally, we employ a grid-based sampling scheme in the region of ongoing population expansion and pro- vide empirical evidence for the power of allele surfing to impart genetic structure on a population, even under conditions of selective neutrality and in a place that lacks strong barriers to gene flow.

}, keywords = {allele surfing, Diversity, expanding population, parasite, population bottleneck}, doi = {10.1111/mec.14997}, url = {https://onlinelibrary.wiley.com/doi/10.1111/mec.14997}, author = {James W. Demastes and David J. Hafner and Mark S. Hafner and Jessica E. Light and Theresa A. Spradling} } @article {94566, title = {Host-parasite associations of the Cratogeomys fumosus species group and their chewing lice, Geomydoecus}, journal = {Biology Faculty Publications}, volume = {31}, year = {2019}, abstract = {

Chewing lice (Phthiraptera: Trichodectidae) and the pocket gophers (Rodentia: Geomyidae) that they inhabit have shared an intimate his- torical association that has made them a textbook study for cophylogeny. Herein, we examine the chewing lice found on pocket gophers of the Cratogeomys fumosus species group using DNA sequence data from the mitochondrial cytochrome c oxidase subunit I gene to determine relationships among lice for comparison to published host phylogeny. Although matrix approaches indicate a correlation between host and parasite genetic distances, cophylogenetic reconstruction methods fail to detect a pattern of widespread cophylogeny. In conclusion, this study provides an exception to the rule of host-parasite cophylogeny that could be the result of the young age of the relationships considered herein and the complex history of the Trans-Mexican Volcanic Belt.
Los piojos masticadores (Phthiraptera: Trichodectidae) y las tuzas (Rodentia: Geomyidae) que habitan, han compartido una asociaci\ón hist\órica \íntima que los ha convertido en un estudio de libro de texto para la cofilogenia. En el presente estudio, examinamos los piojos mas- ticadores que se encuentran en las tuzas del grupo de especies de Cratogeomys fumosus utilizando los datos de secuencias de ADN del gen mitocondrial Citocromo C Oxidasa subunidad I para determinar las relaciones entre los piojos en comparaci\ón con la filogenia publicada del hospedero. Si bien los enfoques matriciales indican una correlaci\ón entre las distancias gen\éticas del hospedero y el par\ásito, los m\étodos de reconstrucci\ón cofilogen\éticos no detectan un patr\ón de cofilogenia generalizada. En conclusi\ón, este estudio, proporciona una excepci\ón a la regla de cofilogenia par\ásito-hospedero que podr\ía ser el resultado de la corta edad de las relaciones consideradas en este documento y la compleja historia del Cintur\ón Volc\ánico Trans-Mexicano.

Authors recommended citation:\ Popinga, Alex; Demastes, James W.; Spradling, Theresa A.; Hafner, David J.; and Hafner, Mark S., \"Host-parasite associations of the Cratogeomys fumosus species group and their chewing lice, Geomydoecus\" (2019). Biology Faculty Publications. 31. https://scholarworks.uni.edu/bio_facpub/31

First published in THERYA, v.10 n.2 (2019), by the Asociacion Mexicana de Mastozoologia A.C. Vol 10 Issue 2 81-89 website URL:\ http://www.revistas-conacyt.unam.mx/therya/index.php/THERYA/article/view/739

}, keywords = {cophylogeny, Cratogeomys, Geomyidae, mtDNA, Trans-Mexican Volcanic Belt.}, doi = {10.12933/therya-19-739}, url = {https://scholarworks.uni.edu/bio_facpub/31}, author = {Alex Popinga and James W. Demastes and Theresa A. Spradling and David J. Hafner and Mark S. Hafner} } @article {94263, title = {Cophylogeny on a Fine Scale: Geomydoecus Chewing Lice and Their Pocket Gopher Hosts, Pappogeomys bulleri}, journal = {Journal of Parasitology}, volume = {98}, year = {2012}, month = {Jan-04-2012}, pages = {262 - 270}, abstract = {

Many species of pocket gophers and their ectoparasitic chewing lice have broadly congruent phylogenies, indicating a history of frequent codivergence. For a variety of reasons, phylogenies of codiverging hosts and parasites are expected to be less congruent for more recently diverged taxa. This study is the first of its scale in the pocket gopher and chewing louse system, with its focus entirely on comparisons among populations within a single species of host and 3 chewing louse species in the Geomydoecus bulleri species complex. We examined mitochondrial DNA from a total of 46 specimens of Geomydoecus lice collected from 11 populations of the pocket gopher host, Pappogeomys bulleri. We also examined nuclear DNA from a subset of these chewing lice. Louse phylogenies were compared with a published pocket gopher phylogeny. Contrary to expectations, we observed a statistically significant degree of parallel cladogenesis in these closely related hosts and their parasites. We also observed a higher rate of evolution in chewing louse lineages than in their corresponding pocket gopher hosts. In addition, we found that 1 louse species (Geomydoecus burti) may not be a valid species, that subspecies within G. bulleri are not reciprocally monophyletic, and that morphological and genetic evidence support recognition of a new species of louse, Geomydoecus pricei.

}, issn = {0022-3395}, doi = {10.1645/GE-2904.1}, url = {http://www.bioone.org/doi/abs/10.1645/GE-2904.1}, author = {James W. Demastes and Theresa A. Spradling and Mark S. Hafner and Spies, Gretchen R. and David J. Hafner and Jessica E. Light} } @article {94262, title = {The Mitochondrial Cytochrome Oxidase Subunit I Gene Occurs on a Minichromosome with Extensive Heteroplasmy in Two Species of Chewing Lice, Geomydoecus aurei and Thomomydoecus minor}, journal = {PLOS ONE}, volume = {11}, year = {2016}, month = {Feb-09-2016}, pages = {e0162248}, abstract = {

In animals, mitochondrial DNA (mtDNA) typically occurs as a single circular chromosome with 13 protein-coding genes and 22 tRNA genes. The various species of lice examined previously, however, have shown mitochondrial genome rearrangements with a range

of chromosome sizes and numbers. Our research demonstrates that the mitochondrial genomes of two species of chewing lice found on pocket gophers, Geomydoecus aurei and Thomomydoecus minor, are fragmented with the 1,536 base-pair (bp) cytochrome-oxidase subunit I (cox1) gene occurring as the only protein-coding gene on a 1,916\–1,964 bp mini- circular chromosome in the two species, respectively. The cox1 gene of T. minor begins with an atypical start codon, while that of G. aurei does not. Components of the non-protein coding sequence of G. aurei and T. minor include a tRNA (isoleucine) gene, inverted repeat sequences consistent with origins of replication, and an additional non-coding region that is smaller than the non-coding sequence of other lice with such fragmented mitochondrial genomes. Sequences of cox1 minichromosome clones for each species reveal extensive length and sequence heteroplasmy in both coding and noncoding regions. The highly vari- able non-gene regions of G. aurei and T. minor have little sequence similarity with one another except for a 19-bp region of phylogenetically conserved sequence with unknown function.

}, doi = {10.1371/journal.pone.0162248}, url = {http://dx.plos.org/10.1371/journal.pone.0162248}, author = {Pietan, Lucas L. and Theresa A. Spradling and James W. Demastes}, editor = {Renfu Shao} } @article {68981, title = {Host behaviour drives parasite genetics at multiple geographic scales: population genetics of the chewing louse, Thomomydoecus minor}, journal = {Molecular Ecology}, volume = {24}, year = {2015}, month = {Jan-08-2015}, pages = {4129 - 4144}, abstract = {

Pocket gophers and their symbiotic chewing lice form a host\–parasite assemblage known for a high degree of cophylogeny, thought to be driven by life history parameters of both host and parasite that make host switching difficult. However, little work to date has focused on determining whether these life histories actually impact louse populations at the very fine scale of louse infrapopulations (individuals on a single host) at the same or at nearby host localities. We used microsatellite and mtDNA sequence data to make comparisons of chewing-louse (Thomomydoecus minor) population subdivision over time and over geographic space where there are different potential amounts of host interaction surrounding a zone of contact between two hybridizing pocket-gopher subspecies. We found that chewing lice had high levels of population isolation consistent with a paucity of horizontal transmission even at the very fine geographic scale of a single alfalfa field. We also found marked genetic discontinuity in louse populations corresponding with host subspecies and little, if any, admixture in the louse genetic groups even though the lice are closely related. The correlation of louse infrapopulation differentiation with host interaction at multi- ple scales, including across a discontinuity in pocket-gopher habitat, suggests that host behaviour is the primary driver of parasite genetics. This observation makes sense in light of the life histories of both chewing lice and pocket gophers and provides a powerful explanation for the well-documented pattern of parallel cladogenesis in pocket gophers and chewing lice.

}, keywords = {cophylogeny, host, inbreeding, parasite population genetics}, doi = {10.1111/mec.13306}, url = {http://doi.wiley.com/10.1111/mec.13306}, author = {Harper, Sheree E. and Theresa A. Spradling and James W. Demastes and Calhoun, Courtney S.} } @inbook {47076, title = {Cophylogeny between pocket gophers and chewing lice}, booktitle = {Tangled trees: phylogeny, cospeciation and coevolution}, year = {2003}, note = {draft manuscript}, month = {2003}, pages = {195 - 220}, publisher = {University of Chicago Press}, organization = {University of Chicago Press}, url = {http://www.phthiraptera.info/sites/phthiraptera.info/files/46177.pdf}, author = {Mark S. Hafner and James W. Demastes and Theresa A. Spradling and David L. Reed}, editor = {Page,Roderic D. M.} } @mastersthesis {39686, title = {Relative rates of molecular evolution in rodents and their symbionts (Coevolution, phylogenetic)}, volume = {Ph.D. thesis}, year = {1997}, month = {1997}, pages = {175}, school = {Louisiana State University and Agricultural and Mechanical College}, author = {Theresa A. Spradling} } @article {39397, title = {Pocket gophers and chewing lice: a test of the maternal transmission hypothesis}, journal = {Molecular Ecology}, volume = {7}, year = {1998}, month = {1998}, pages = {1065 - 1069}, abstract = {

The life-history traits of pocket gophers and their chewing lice suggest that there is little opportunity for transmission of parasites among pocket gophers, with the exception of transmission from mother to offspring. Herein, we test the hypothesis that lice are transmitted maternally by using an indirect approach that compares the distribution of louse populations to the distribution of mitochondrial DNA haplotypes in the pocket gophers. Comparison of the chewing louse distributions to the distribution of mtDNA haplotypes for the gophers revealed no significant concordance, and thus falsifies the maternal transmission hypothesis.

}, keywords = {coevolution, colonization, geomydoecus, Geomyidae, host, Mallophaga, mitochondrial dna, mtDNA, parasite, populations, RFLP, thomomys bottae, trichodectidae}, url = {http://www.phthiraptera.info/sites/phthiraptera.info/files/0842.pdf}, author = {James W. Demastes and Mark S. Hafner and David J. Hafner and Theresa A. Spradling} } @article {39398, title = {Age and movement of a hybrid zone: Implications for dispersal distance in pocket gophers and their chewing lice}, journal = {Evolution}, volume = {52}, year = {1998}, month = {1998}, pages = {278 - 282}, abstract = {

Historical flood records for the Rio Grande Valley of New Mexico suggest that a pocket gopher (Thomomys bonae) hybrid zone previously thought to be 10,000 years old may actually be closer to 50 years old. Measured zone width (defined genetically) is consistent with the hypothesis of recent contact, if we assume a reasonable dispersal distance of approximately 400 m/year for pocket gophers. A five-year study of movement of the contact zone between the two species of chewing lice that parasitize these pocket gophers also is consistent with the hypothesis of recent origin of the zone.

}, keywords = {Chewing lice, cline, coevolution, differentiation, dispersal, genetic, Geomyidae, gopher, host parasite, hybrid, lice, models, pocket, populations, rodentia, zones}, doi = {10.2307/2410946}, url = {http://www.jstor.org/stable/2410946?seq=1$\#$page_scan_tab_contents}, author = {Mark S. Hafner and James W. Demastes and David J. Hafner and Theresa A. Spradling and Sudman,Philip D. and Nadler,Steven A.} } @article {38719, title = {Disparate rates of molecular evolution in cospeciating hosts and parasites}, journal = {Science}, volume = {265}, year = {1994}, month = {1994}, pages = {1087 - 1090}, abstract = {

DNA sequences for the gene encoding mitochondrial cytochrome oxidase I in a group of rodents (pocket gophers) and their ectoparasites provide evidence for cospeciation and reveal different rates of molecular evolution in the hosts and their parasites. The overall rate of nucleotide substitution (both silent and replacement changes) is approximately three times higher in lice, and the rate of synonymous substitution (based on analysis of fourfold degenerate sites) is approximately an order of magnitude greater in lice. The difference in synonymous substitution rate between lice and gophers correlates with a difference in similar magnitude in generation times.

}, keywords = {base, differentiation, genetic, genome, geomydoecus, Geomyidae, gopher, Mallophaga, mitochondrial dna, Phylogeny, pocket, rodentia, substitutions, trees, trichodectidae}, url = {http://www.phthiraptera.info/sites/phthiraptera.info/files/0004.pdf}, author = {Mark S. Hafner and Sudman,Philip D. and Villablanca,Francis X. and Theresa A. Spradling and James W. Demastes and Nadler,Steven A.} }