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Efforts to remove invasive species may benefit native species, but the effects can be complex and unpredictable. Thus, studies of invasive-species removal provide important information for guiding management and providing insight about variation in post-removal impacts within the community. Using southern pine-grassland ecosystems as a model system, we hypothesized that removal of the long-established red-imported fire ant (Solenopsis invicta, hereafter RIFA) would positively influence altricial Peromyscus species, due to increased survival of young in the nest and thus increased recruitment to the population, but would not impact semi-precocial hispid cotton rats (Sigmodon hispidus), which are mobile more quickly after birth and thus at less risk of depredation by RIFA. We compared small mammal populations on sites treated with a granular insecticide (Extinguish Plus) to remove RIFA in southwestern Georgia, United States, from April 2018 to December 2019. As expected, we detected no difference in cotton rat recruitment. However, contrary to our prediction, the same was true for cotton mice (Peromyscus gossypinus) and oldfield mice (Peromyscus polionotus). We found RIFA removal increased survival both of cotton rats and cotton mice, increasing average population rate of change (λ) on treated sites during the study period. In contrast, we observed lower survival of oldfield mice, with similar λ estimates on treated and untreated sites, but low sample sizes were problematic for this species. Our results show that removal of invasive species can have positive impacts for native species, but both the magnitude of RIFA effects on small mammals and mechanisms by which impacts occur are complex.

A significant limitation in biodiversity conservation has been the effective implementation of laws and regulations that protect species' habitats from degradation. Flexible, efficient, and effective monitoring and enforcement methods are needed to help conservation policies realize their full benefit. As remote sensing data become more numerous and accessible, they can be used to identify and quantify land-cover changes and habitat loss. However, these data remain underused for systematic conservation monitoring in part because of a lack of simple tools. We adapted 2 algorithms that automatically identify differences between pairs of images. We used free, publicly available satellite data to evaluate their ability to rapidly detect land-cover changes in a variety of land-cover types. We compared algorithm predictions with ground-truthed results at 100 sites of known change in the United States. We also compared algorithm predictions to manually created polygons delineating anthropogenic change in 4 case studies involving imperiled species' habitat: oil and gas development in the range of the Greater Sage Grouse (Centrocercus urophasianus); sand mining operations in the range of the dunes sagebrush lizard (Sceloporus arenicolus); loss of Piping Plover (Charadrius melodus) coastal habitat after Hurricane Michael (2018); and residential development in St. Andrew beach mouse (Peromyscus polionotus peninsularis) habitat. Both algorithms effectively discriminated between pixels corresponding to land-cover change and unchanged pixels as indicated by area under a receiver operating characteristic curve0.90. The algorithm that was most effective differed among the case-study habitat types, and both effectively delineated habitat loss as indicated by low omission (min. = 0.0) and commission (min. = 0.0) rates, and moderate polygon overlap (max. = 47%). Our results showed how these algorithms can be used to help close the implementation gap of monitoring and enforcement in biodiversity conservation. We provide a free online tool that can be used to run these analyses (https://conservationist.io/habitatpatrol).Respaldo a la Conservación de Hábitat con la Detección Automatizada de Cambio en Google Earth Resumen Una limitación significativa en la conservación de la biodiversidad ha sido la implementación efectiva de las leyes y regulaciones que protegen los hábitats de las especies de la degradación. El monitoreo flexible, eficiente y efectivo y los métodos de aplicación son necesarios para que las normas de conservación puedan llevar a cabo su potencial completo. Conforme los datos de telemetría se vuelven cada vez más numerosos y accesibles, su uso puede extenderse a la identificación y cuantificación de los cambios en la cobertura del suelo y la pérdida del hábitat. Sin embargo, estos datos todavía están subutilizados en cuanto al monitoreo sistemático de la conservación en parte debido a la falta de herramientas simples y sencillas. Adaptamos dos algoritmos que identifican automáticamente las diferencias entre pares de imágenes. Utilizamos datos satelitales gratuitos y disponibles para el público para con ellos evaluar la habilidad que tienen los algoritmos para detectar rápidamente los cambios en la cobertura del suelo dentro de una variedad de tipos de cobertura de suelo. Comparamos las predicciones algorítmicas con los resultados de algunas investigaciones en 100 sitios con cambios conocidos en los Estados Unidos. También comparamos las predicciones algorítmicas con polígonos creados manualmente que delinean el cambio antropogénico en cuatro estudios de caso que involucran al hábitat de una especie en peligro: desarrollos de petróleo y gas en la distribución de Centrocercus urophasianus; minas de arena en la distribución de Sceloporus arenicolus; la pérdida del hábitat costero de Charadrius melodus después del huracán Michael (2018); y los desarrollos residenciales en el hábitat de Peromyscus polionotus peninsularis. Ambos algoritmos discriminaron efectivamente entre los píxeles que correspondían al cambio en la cobertura del suelo y los píxeles sin cambio así indicados por el área bajo la curva de característica de receptor operante0.90. El algoritmo más efectivo difirió entre los tipos de hábitat para los estudios de caso, mientras que ambos algoritmos delinearon efectivamente la pérdida de hábitat así indicada por la baja tasa de omisión (min. = 0.0) y comisión (min. = 0.0) y el traslape moderado de polígonos (max. = 47%). Nuestros resultados mostraron cómo pueden usarse estos algoritmos para ayudar a cerrar la brecha en la implementación del monitoreo y aplicación en la conservación de la biodiversidad. Proporcionamos una herramienta gratuita en línea que puede usarse para realizar estos análisis: https://conservationist.io/habitatpatrol.

Identifying the genetic basis of repeatedly evolved traits provides a way to reconstruct their evolutionary history and ultimately investigate the predictability of evolution. Here, we focus on the oldfield mouse (Peromyscus polionotus), which occurs in the southeastern United States, where it exhibits considerable coat-color variation. Dorsal coats range from dark brown in mice inhabiting mainland habitat to near white on the white-sand beaches of the southeastern US, where light pelage has evolved independently on Florida’s Gulf and Atlantic coasts as an adaptation to visually hunting predators. To facilitate genomic analyses in this species, we first generated a high-quality, chromosome-level genome assembly of P. polionotus subgriseus. Next, in a uniquely variable mainland population that occurs near beach habitat (P. p. albifrons), we scored 23 pigment traits and performed targeted resequencing in 168 mice. We find that variation in pigmentation is strongly associated with a ~2 kb region approximately 5 kb upstream of the Agouti-signaling protein (ASIP) coding region. Using a reporter-gene assay, we demonstrate that this regulatory region contains an enhancer that drives expression in the dermis of mouse embryos during the establishment of pigment prepatterns. Moreover, extended tracts of homozygosity in this region of Agouti indicate that the light allele has experienced recent and strong positive selection. Notably, this same light allele appears fixed in both Gulf and Atlantic coast beach mice, despite these populations being separated by >1,000km. Given the evolutionary history of this species, our results suggest that this newly identified Agouti enhancer allele has been maintained in mainland populations as standing genetic variation and from there has spread to, and been selected in, two independent beach mouse lineages, thereby facilitating their rapid and parallel evolution.

Identifying techniques for conducting frequent, effective, and inexpensive monitoring of small mammals can be challenging. Traditional approaches such as livetrapping can be laborious, expensive, detrimental to animal health, and ineffective. Passive approaches such as tracking (e.g., from tracks on the ground or footprints collected at a tracking station) have been shown to lessen those burdens, but a problem with tracking, particularly for rodents, is the uncertainty in identifying species from footprints. To address the need for a more accurate method of identifying small mammal tracks, we measured footprints from live-captured rodents and developed a classification tree for distinguishing between subspecies and species using footprint widths treated as having known or unknown identification. We captured rodents within or near the coastal dunes of Florida and Alabama with a focus on areas occupied by threatened and endangered beach mice Peromyscus polionotus subspp., whose populations warrant regular monitoring but whose tracks are not easily distinguished from those of some sympatric species. We measured 6,996 front and hind footprints from 540 individuals across eight species. The overall accuracy of our classification tree was 82.6% and we achieved this using only the front footprint width. Footprint width cutoffs for species identification were < 5.5 mm for house mice Mus musculus, 5.5–6.7 mm for beach mice, and 6.7–8.3 mm for cotton mice Peromyscus gossypinus. We were most successful in confirming the identity of beach mice: we correctly classified approximately 94% of beach mice, while we misclassified fewer than 6% as house mice and fewer than 1% as cotton mice. When we input a beach mouse individual into the classification tree as of an unknown species, we correctly identified 78.1% of individuals as beach mice from their tracks, and most incorrect identifications were of house mouse tracks. Our study demonstrates that researchers can identify sympatric rodent species in coastal dune communities from tracks using quantitative classification based on footprint width. Accurate identification of beach mice or other imperiled species from tracks has important management implications. Not only can wildlife managers determine the presence of a species accurately, but they can monitor populations with considerably less effort than livetrapping requires. Although our study was specific to coastal dune communities, our methods could be adapted for the creation of a classification tree for identifying tracks from suites of species in other areas.

Species across the rodent genus Peromyscus have become prominent models for studying diverse mechanistic and evolutionary processes, including chromosome evolution, infectious disease transmission and human health, ecological adaptation, coat color variation, and parental care. Supporting such diverse research programs has been the development of genetic and genomic resources for species within this genus, including genome data, interspecific chromosome homologies, and a recently developed genetic map. Based on interspecific hybrids between the deer mouse (Peromyscus maniculatus bairdii) and the old-field, or beach, mouse (Peromyscus polionotus) and backcross progeny to Peromyscus maniculatus, a linkage map was developed based on 190 genes and 141 microsatellite loci. However, resolution of several linkage groups with respect to chromosome assignment was lacking and four chromosomes (8, 16, 20, and 21) were not clearly delineated with linkage data alone. The recent development of a high-density map for Peromyscus proved ineffective in resolving chromosome linkage for these four chromosomes. Herein we present an updated linkage map for Peromyscus maniculatus, including linkage group-chromosome assignments, using fluorescence in situ hybridization mapping of BACs and whole chromosome paints. We resolve the previously conflicting chromosome assignment of linkage groups to Chromosomes 8, 16, 20, and 21, and confirm the assignment of linkage groups to Chromosomes 18 and 22. This updated linkage map with validated chromosome assignment provides a solid foundation for chromosome nomenclature for this species.

Track tubes are a noninvasive, efficient method to monitor populations of small mammals that can be implemented on a large landscape scale and are a cost-effective approach for certain sampling situations. As with all field sampling tools, modifications are made depending on research objectives, habitat being sampled, and target species. We conducted two experiments with the objective to increase efficiency and decrease labor while retaining high detection probabilities as part of an Annual Multi-Agency Regional Southeastern Beach Mouse Peromyscus polionotus niveiventris Habitat Occupancy Survey. We conducted studies along a contiguous 72-km coastline of the Cape Canaveral Barrier Island Complex in east-central Florida, USA, that includes the Kennedy Space Center, Cape Canaveral Air Force Station, and Canaveral National Seashore. We conducted the experiments to address several issues that had regularly compromised our survey data. One experiment assessed the ideal length of deployment times for track tubes in various habitat types with multiple species where southeastern beach mice were previously detected. Another experiment, determined how to restrict certain meso-mammal species (raccoons Procyon lotor, and eastern spotted skunks Spilogale putorius) from knocking over the tubes or reaching into the tubes, thus reducing disturbance that results in missing data; or from entering the tubes (cotton rats Sigmodon hispidus), thereby obscuring any potential or actual footprints of the southeastern beach mouse or other targeted species. We observed an increase in the detection rate of southeastern beach mice in track tubes with increased nights of deployment (likelihood ratio test χ2 = 18.71, df = 3, P < 0.001) with the greatest increase between 3 nights and 6 nights and apparent leveling off between nights 9 and 12 and a large decrease in the detection rate of southeastern beach mice in track tubes with 0.5-in. (1.3-cm) excluders compared with the other-size excluders (likelihood ratio test χ2 = 167.89, df = 5, P < 0.001). We also found that 1-in. (2.5-cm) excluders prevented access by meso-mammals or entry by cotton rats and did not adversely affect the detection of either beach mice or cotton mice Peromyscus gossypinus, but did reduce disturbance and resulted in fewer missing data. These statistically significant process improvements have application for others involved with small mammal monitoring and species management.

We used Cormack–Jolly–Seber capture–recapture analyses to investigate differences in monthly survival of the southeastern beach mouse (Peromyscus polionotus niveiventris) between sexes, between juveniles and adults, and effects due to the presence of transients that can bias survival estimates. We accounted for transients (e.g., nonresidents) by distinguishing survival for the initial month after an individuals' 1st capture from monthly survival after the 1st recapture. Survival estimates for 1st captures and recaptures of females were 0.70 and 0.78, respectively. Survival estimates for 1st captures and recaptures of males were 0.74 and 0.80, respectively. Our results showed that a comparably small proportion of transients (females = 0.10; males = 0.08) can bias survival estimates.

Summary Parental care is essential for the survival of mammals, yet the mechanisms underlying its evolution remain largely unknown. Here we show that two sister species of mice, Peromyscus polionotus and P. maniculatus, have large and heritable differences in parental behaviour. Using quantitative genetics, we identify 12 genomic regions that affect parental care, eight of which have sex-specific effects, suggesting that parental care can evolve independently in males and females. Furthermore, some regions affect parental care broadly, whereas others affect specific behaviours, such as nest building. Of the genes linked to differences in nest-building behaviour, vasopressin is differentially expressed in the hypothalamus of the two species, with increased levels associated with less nest building. Using pharmacology in Peromyscus and chemogenetics in Mus, we show that vasopressin inhibits nest building but not other parental behaviours. Together, our results indicate that variation in an ancient neuropeptide contributes to interspecific differences in parental care.

P. polionotus, South Carolina, Lexington Co. (U40254)., Published as part of Greenbaum, Ira F., Honeycutt, Rodney L. & Chirhart, Scott E., 2019, Taxonomy And Phylogenetics Of The Peromyscus Maniculatus Species Group, pp. 559-575 in Special Publications of the Museum of Texas Tech University 71 on page 567, DOI: 10.5281/zenodo.7221125

Peromyscus polionotus (Wagner 1843) Mus polionotus Wagner, 1843:52. Hesperomys niveiventris (Chapman), 1889:18. Sitomys niveiventris subgriseus Chapman, 1893:341. Peromyscus phasma subgriseus Bangs, 1898c:199. Peromyscus subgriseus subgriseus Bangs, 1898c:200. Peromyscus subgriseus rhoadsi Bangs, 1898c:201. Peromyscus subgriseus arenarus Bangs, 1898c:202-203. Peromyscus subgriseus baliolus Bangs, 1898c:214-215. Peromyscus polionotus Osgood, 1907:49. Peromyscus polionotus niveiventris Osgood, 1909:105. Peromyscus polionotus phasma Osgood, 1909:107. Peromyscus polionotus rhoadsi Osgood, 1909:107. Peromyscus polionotus albifrons Osgood, 1909:108. Peromyscus polionotus leucophalus A. H. Howell, 1920:239. Peromyscus polionotus decoloratus A. H. Howell, 1939:363. Peromyscus polionotus peninsularis A. H. Howell, 1939:364. P[eromyscus]. p[olionotus].subgriseus Schwartz, 1954:562. Peromyscus polionotus lucubrans Schwartz, 1954:564. Peromyscus polionotus colemani Schwartz, 1954:566. Peromyscus polionotus ammobates Bowen, 1968:16. Peromyscus polionotus griseobaracatus Bowen, 1968:16. Peromyscus polionotus trissyllepsis Bowen, 1968:17. Peromyscus polionotus allophrys Bowen, 1968:18. Peromyscus polionotus sumneri Bowen, 1968:20. Holotype.— Osgood (1909) examined the type specimen (catalog number) on exhibit at the museum of the Polytechnic in Zurich. Skull and tail vertebrae were still in the specimen. The specimen initially was identified by Wagner (1843) as Mus polionotus, from somewhere in Georgia, United States. Osgood noted the identity of the specimen was most probably assignable to P. p. subgriseus. Type locality.— Little information is available for determination of the type locality of P. polionotus. As researched and reviewed by Osgood (1909), it appears that Georgia, United States may be as precise a locality as is possible to determine. Subspecies.— Hall (1981) recognized the following 16 subspecies: P. p. albifrons, P. p. allophrys, P. p. ammobates, P. p. colemani, P. p. decoloratus, P. p. griseobaracatus, P. p. leucophalus, P. p. lucubrans, P. p. niveiventris, P. p. peninsularis, P. p. phasma, P. p. polionotus, P. p. rhoadsi, P. p. subgriseus, P. p. sumneri, and P. p. trissyllepsis. Diagnosis.— Size is very small for the species group (Osgood 1909). External measurements obtained from Osgood (1909), for several of the subspecies now assigned to P. polionotus, indicated a total length that ranged between 125–137 mm; (= 131 mm) and a tail length that ranged between 41–52 mm; (= 46.5 mm). Dorsal pelage is gray along back and shoulders with sides containing a mixture of gray and light cinnamon coloration. Tail is short and bicolored. Distribution.— This species is restricted to the southeastern United States and ranges from northeastern Mississippi to western South Carolina, southward through Alabama and Georgia to central Florida (Osgood 1909). Comparisons.— A member of the P. maniculatus species group. With the exception of slightly larger auditory bullae the skull is much smaller than other members of the genus and most closely resembles that of P. maniculatus (Osgood 1909; Hall 1981). Cyt b sequences (this study) indicated that P. polionotus differs from P. maniculatus (sensu stricto) and P. sonoriensis by 5.12% and 4.71% respectively. Genetic differentiation (= 0.50%) based on DNA sequences obtained from 13 individuals of P. polionotus indicated the lowest level of genetic divergence for members of the P. maniculatus species group. The small geographic distribution of this species may explain this observation. Remarks.— Thirteen samples were examined in this study that are assignable to P. polionotus. Of these samples, all were from Florida, given that the type locality is unknown we could not estimate the relative proximity; however, given that no other P. maniculatus species occurs in this area we assume these samples are good representatives of P. polionotus. Although the karyotype of P. polionotus (FN = 69–71; Te and Dawson 1971) is unique relative to those of other species in the P. maniculatus group, several synapomorphies place it in this group (Robbins and Baker 1981; Stangl and Baker 1984). However, determining the phylogenetic association of P. polionotus to other members of the P. maniculatus species group has been problematic. Hooper (1968), and later Greenbaum et al. (1978), viewed P. polionotus to be an earlier peripheral isolate of grassland forms of P. maniculatus (bairdi and pallescens). Although allozyme and chromosome data (Greenbaum 1978; Avise et al. 1979; Robbins and Baker 1981; Stangl and Baker 1984) indicated that P. polionotus was sister to a clade containing taxa now recognized as P. sonoriensis and P. keeni, Avise et al. (1983) suggested that P. polionotus was paraphyletic with P. maniculatus and that P. polionotus may represent a peripheral population of P. maniculatus that underwent speciation approximately 1.5 mya. Herein, this species is loosely allied (no nodal support) with clades I (P. sonoriensis), K (P. maniculatus), and L (P. labecula) but may have differentiated at a more recent date, approximately1.40 mya from the putative common ancestor with P. sonoriensis (Fig. 3)., Published as part of Bradley, Robert D., Francis, James Q., Platt II, Roy N., Soniat, Taylor J., Alvarez, Daysi & Lindsey, Laramie L., 2019, Mitochondrial Dna Sequence Data Indicate Evidence For Multiple Species Within Peromyscus Maniculatus, pp. 1-59 in Special Publications of the Museum of Texas Tech University 70 on pages 23-24, DOI: 10.5281/zenodo.7221903, {"references":["Wagner, A. 1843. Diagnosen neuer Arten Brasiliscer Handfluger. Archiv fur Naturgeschichte 9: 366.","Chapman, F. M. 1889. Preliminary description of two apparently new species of the genus Hesperomys from Florida. Bulletin of the American Museum of Natural History 2: 117.","Chapman, F. M. 1893. Description of two new races of mammals from southern Florida, with remarks on Sitomys nivenientris. Bulletin of theAmerican Museum of Natural History 5: 339 - 341.","Bangs, O. 1898 c. The Land Mammals of Peninsular Florida and the Coast Region of Georgia. Proceedings of the Boston Society of Natural History 28: 157 - 236.","Osgood, W. H. 1907. Some unrecognized and misapplied names of American mammals. Proceedings of the Biological Society of Washington 20: 43 - 52.","Osgood, W. H. 1909. Revision of the Mice of the American Genus Peromyscus. NorthAmerican Fauna 28: 1 - 285.","Howell, A. H. 1920. Description of a new species of beach mouse from Florida. Journal of Mammalogy 1: 237 - 240.","Howell, A. H. 1939. Descriptions of five new mammals from Florida. Journal of Mammalogy 20: 363 - 365.","Schwartz, A. 1954. Oldfield mice, Peromyscus polionotus, of South Carolina. Journal of Mammalogy 35: 561 - 569.","Bowen, W. W. 1968. Variation and evolution of gulf coast populations of beach mice, Peromyscus polionotus. Bul- letin of the Florida State Museum 12: 1 - 91.","Hall, E. R. 1981. The mammals of North America. 2 nd ed. John Wiley & Sons, Inc. New York 1181 pp.","Robbins, L. W., and R. J. Baker. 1981. An assessment of the nature of chromosomal rearrangements in 18 species of Peromyscus (Rodentia: Cricetidae). Cytogenetic and Genome Research 31: 194 - 202.","Stangl Jr., F. B., and R. J. Baker. 1984. Evolutionary relationships in Peromyscus: congruence in chromosomal, genic, and classical data sets. Journal of Mammalogy 65: 643 - 654.","Hooper, E. T. 1968. Classification. Pp. 27 - 74, in Biology of Peromyscus (Rodentia) (J. A. King, ed.). Special Publica- tion, American Society of Mammalogists 2: 1 - 593.","Greenbaum, I. F., R. J. Baker, and P. R. Ramsey. 1978. Chromosomal evolution and the mode of speciation in three species of Peromyscus. Evolution 32: 646 - 654.","Avise, J. C., M. H. Smith, and R. K. Selander. 1979. Biochemical polymorphism and systematics in the genus Peromyscus. VII. Geographic differentiation in members of the truei and maniculatus species groups. Journal of Mammalogy 60: 177 - 192.","Avise, J. C., J. F. Shapira, S. W. Daniel, C. F. Aquadro, and R. A. Lansman. 1983. Mitochondrial DNA differentiation during the speciation process in Peromyscus. Molecular Biology and Evolution 1: 38 - 56."]}

Folic acid and other dietary methyl donors are widely supplemented due to their ability to prevent neural tube defects. Dietary methyl donors are also added to other consumables such as energy drinks due to energy-promoting attributes and other perceived benefits. However, there is mounting evidence that indicates developmental exposure to high levels of dietary methyl donors may have deleterious effects. We assessed whether behavior was affected in the social North American rodent species Peromyscus polionotus exposed to a diet enriched with folic acid, Vitamin B12, choline, and betaine/trimethylglycine(TMG). P. polionotus (PO) animals are very social and exhibit little repetitive behavior, particularly compared to their sister species, P. maniculatus. We assayed the effects of dietary methyl-donor supplementation on anxiety-like repetitive and social behaviors by testing young adult animals for novel cage behavior and in social interaction tests. Animals of both sexes exposed to the diet had increased repetitive behaviors and reduced social interactions. Males exposed to the diet became more aggressive compared to their control counterparts. Since methyl-diet animals were larger than control animals, DEXA scans and hormone analyses were performed. Animals exposed to the diet had increased body fat percentages and experienced hormonal changes typically associated with excess fat storage and anxiety-like behavior changes. Therefore, these data suggest the wide use of these dietary supplements makes further investigation imperative.

Barrier island taxa provide an opportunity to investigate recent evolutionary processes, such as colonization and isolation of recently diverged taxa, and provide important insights into understanding contemporary diversity and the assessment of conservation units. Using rapidly evolving genetic markers (mitochondrial DNA and microsatellites), we studied the Atlantic coast beach mouse subspecies (Peromyscus polionotus decoloratus, P. p. niveiventris, and P. p. phasma). Our data indicate that each of the extant coastal subspecies (P. p. niveiventris and P. p. phasma) is comprised of unique haplotypes indicative of their isolation, while the extinct subspecies, P. p. decoloratus, contain a single haplotype, which was shared with P. p. phasma. Moreover, all the coastal haplotypes originate from a single mainland haplotype found in central Florida, USA. The microsatellite data indicated high levels of genetic structure among our sampled populations. Additionally, these data group the populations into three distinct genetic clusters, with each of the extant coastal subspecies belonging to their own cluster and the mainland individuals forming a separate cluster. The extant Atlantic coast beach mice are on separate evolutionary trajectories, thus representative of separate taxonomic units. Therefore, the data support that two extant subspecies on the Florida Atlantic coast fit the Distinct Population Segment designation and should be managed and conserved as two separate independent units.

A previously unrecognized species of hymenolepidid cestode attributable to Hymenolepis is described based on specimens in Peromyscus polionotus, oldfield mouse, from Georgia near the southeastern coast of continental North America. Specimens of Hymenolepis folkertsi n. sp. differ from those attributed to most other species in the genus by having testes arranged in a triangle and a scolex with a prominent rostrum-like protrusion. The newly recognized species is further distinguished by the relative position and length of the cirrus sac, shape of seminal receptacle, and relative size of external seminal vesicle and seminal receptacle. Hymenolepidid cestodes have sporadically been reported among the highly diverse assemblage of Peromyscus which includes 56 distinct species in the Nearctic. Although the host genus has a great temporal duration and is endemic to the Nearctic, current evidence suggests that tapeworm faunal diversity reflects relatively recent assembly through bouts of host switching among other cricetid, murid, and geomyid rodents in sympatry.

A central challenge in biology is to understand how innate behaviors evolve between closely related species. One way to elucidate how differences arise is to compare the development of behavior in species with distinct adult traits. Here, we report that Peromyscus polionotus is strikingly precocious with regard to burrowing behavior, but not other behaviors, compared to its sister species P. maniculatus . In P. polionotus , burrows were excavated as early as 17 days of age, while P. maniculatus did not build burrows until 10 days later. Moreover, the well-known differences in burrow architecture between adults of these species -- P. polionotus adults excavate long burrows with an escape tunnel, while P. maniculatus dig short, single-tunnel burrows -- were intact in juvenile burrowers. To test whether this juvenile behavior is influenced by early-life environment, pups of both species were reciprocally cross-fostered. Fostering did not alter the characteristic burrowing behavior of either species, suggesting these differences are genetic. In backcross F2 hybrids, we show that precocious burrowing and adult tunnel length are genetically correlated, and that a single P. polionotus allele in a genomic region linked to adult tunnel length is predictive of precocious burrow construction. The co-inheritance of developmental and adult traits indicates the same genetic region -- either a single gene with pleiotropic effects, or closely linked genes -- acts on distinct aspects of the same behavior across life stages. Such genetic variants likely affect behavioral drive (i.e. motivation) to burrow, and thereby affect both the development and adult expression of burrowing behavior.

Chen, Q.; Wang, H.; Wang, L.; Tawes, R., and Rollman D., 2014. Predicting the impacts of tropical cyclones and sea-level rise on beach mouse habitat. Alabama beach mouse (ABM) (Peromyscus polionotus ammobates) is an important component of the coastal dune ecosystem along the Gulf of Mexico. Due to habitat loss and degradation, ABM is federally listed as an endangered species. In this study, we examined the impacts of storm surge and wind waves, which are induced by hurricanes and sea-level rise (SLR), on the ABM habitat on Fort Morgan Peninsula, Alabama, using advanced storm surge and wind wave models and spatial analysis tools in geographic information systems (GIS). Statistical analyses of the long-term historical data enabled us to predict the extreme values of winds, wind waves, and water levels in the study area at different return periods. We developed a series of nested domains for both wave and surge modeling and validated the models using field observations of surge hydrographs and high ...

The spatial configuration of habitat and the frequency of disturbances through time could have interacting effects on population viability. With this in mind, we assessed the rate of post-hurricane recovery and long term viability of the Alabama beach mouse (Peromyscus polionotus ammobates). We collected detection/nondetection data across the range of the Alabama beach mouse for four years subsequent to hurricanes Ivan and Katrina, and then fit a dynamic patch occupancy model to these data using hierarchical Bayesian methods. We converted remotely sensed data into habitat classes, and then mapped site survival probability over the entire range of the species. These estimates were then used to parameterize a spatially-explicit population viability analysis. Our occupancy modeling demonstrates that the probability of patch occupancy increased from 0.16 to 0.67, with occupancy in the surveyed patches approaching an asymptote by the third post-hurricane summer. The viability analysis suggests that extinction probability increases nonlinearly with monotonic increases in both habitat loss and hurricane frequency. Extinction risk is sensitive to the regularity of catastrophic hurricanes; consecutive hurricanes dramatically increase extinction risk, further suggesting that the effect of global climate change on hurricane regimes may have a large effect on the probability of long-term persistence. A mild interaction between habitat loss and hurricane frequency occurs when extinction probability is relatively low, but disappears as extinction probability increases. Our results indicate that extinction risk is a complex function of multiple interacting drivers.

Quantifying habitat occupancy of the southeastern beach mouse Peromyscus polionotus niveiventris is important for managing this threatened species throughout its limited range. Tracking tubes were used to detect the southeastern beach mouse in coastal areas on the federal lands of the Kennedy Space Center, Cape Canaveral Air Force Station, and Canaveral National Seashore. Because this method relied on observations of footprints, detections of beach mice were confounded by the co-occurrence of cotton mice Peromyscus gossypinus, which have wider but slightly overlapping footprint widths. Mice of both species were captured and footprinted using tracking tubes to collect a database of footprints of known identity. These data were used to develop a Bayesian hierarchical model of the cutoff width at which a print could be assigned as a beach mouse with a known probability of error. Specifically, within the model, observed footprint widths were used to estimate a mean and variance of footprint width for each species, while accounting for variation between individual mice. Then, a distribution of new footprint widths was generated for each species by drawing from their modeled distributions. Finally, the new footprints were compared with a range of potential cutoff widths to evaluate the proportion of times the correct decision to exclude or accept the footprint was made. We graphically evaluated the performance of the cutoff widths and chose one that traded off between reducing false positives and retaining more correct detections for use in occupancy models. We explored the use of the cutoff width using occupancy models that allow for false-positive detections, and found that the use of the cutoff performed as expected. Over 40% of primary dune habitat on the Kennedy Space Center was occupied by beach mice during the period sampled. The proportion of vegetated habitat at a site had a negative influence on detection probability. No ecological covariates had a measurable influence on beach mouse occupancy, probably due to the limited range of environmental variation in the sampled region. The use of a cutoff for footprint width resulted in a reliable method to deal with false-positive detections in tracking tubes with small mammals and allowed the use of occupancy models that rely on certain detection.

Deer mice (Peromyscus) are the most common native North American mammals, and exhibit great natural genetic variation. Wild-derived stocks from a number of populations are available from the Peromyscus Genetic Stock Center (PGSC). The PGSC also houses a number of natural variants and mutants (many of which appear to differ from Mus). These include metabolic, coat-color/pattern, neurological, and other morphological variants/mutants. Nearly all these mutants are on a common genetic background, the Peromyscus maniculatus BW stock. Peromyscus are also superior behavior models in areas such as repetitive behavior and pair-bonding effects, as multiple species are monogamous. While Peromyscus development generally resembles that of Mus and Rattus, prenatal stages have not been as thoroughly studied, and there appear to be intriguing differences (e.g., longer time spent at the two-cell stage). Development is greatly perturbed in crosses between P. maniculatus (BW) and Peromyscus polionotus (PO). BW females crossed to PO males produce growth-restricted, but otherwise healthy, fertile offspring which allows for genetic analyses of the many traits that differ between these two species. PO females crossed to BW males produce overgrown but severely dysmorphic conceptuses that rarely survive to late gestation. There are likely many more uses for these animals as developmental models than we have described here. Peromyscus models can now be more fully exploited due to the emerging genetic (full linkage map), genomic (genomes of four stocks have been sequenced) and reproductive resources.

Motivated by conservation concerns, we assessed whether Sigmodon hispidus (hispid cotton rat) affects the realized niche of Peromyscus polionotus ammobates (Alabama beach mouse). After experimentally removing S. hispidus and accounting for spatial autocorrelation in our data, we found weak evidence for an increase in habitat use by P. p. ammobates at locations previously occupied by S. hispidus. This pattern is consistent with a niche-constriction hypothesis, and was not observed on 2 control grids where removals were not conducted. Our results suggest that removal of S. hispidus from habitat remnants immediately following catastrophic hurricanes ameliorates extinction risk of P. p. ammobates, but we also stress the inferential limitations of our data and the need for further investigation of competitive interactions between these species.

Landscape features that promote animal movement contribute to functional habitat connectivity. Factors that affect the use of landscape features, such as predation risk, may alter functional connectivity. We identify factors important to functional habitat connectivity by quantifying movement patterns of the Santa Rosa beach mouse (Peromyscus polionotus leucocephalus) in relation to landscape features and by examining how ambient perceived predation risk, which is altered by moon phase, interacts with landscape features. We use track paths across the sand to relate the probability that beach mice cross gaps between vegetation patches to gap width, patch quality, landscape context and moon phase. Overall activity levels were lower during full versus new moon nights, demonstrating that beach mice respond negatively to moonlight. Gap crossing was more likely during new moon nights (25 % of gaps crossed vs. 7 % during full moon nights), and across narrower gaps ( 11.75 m2). This study suggests that vegetation recovery is necessary for functional connectivity in post-hurricane landscapes commonly inhabited by beach mice and provides initial guidelines for restoring landscape connectivity. More broadly, this study highlights the importance of considering predation risk when quantifying landscape connectivity, as landscape features that facilitate connectivity when predation risk is low may be ineffective if predation risk increases over time or across space.

Relative to morphological traits, we know little about how genetics influence the evolution of complex behavioural differences in nature 1 . It is unclear how the environment influences natural variation in heritable behaviour 2 , and whether complex behavioural differences evolve through few genetic changes, each affecting many aspects of behaviour, or through the accumulation of several genetic changes that, when combined, give rise to behavioural complexity 3 . Here we show that in nature, oldfield mice (Peromyscus polionotus) build complex burrows with long entrance and escape tunnels, and that burrow length is consistent across populations, although burrow depth varies with soil composition. This burrow architecture is in contrast with the small, simple burrows of its sister species, deer mice (P. maniculatus). When investigated under laboratory conditions, both species recapitulate their natural burrowing behaviour. Genetic crosses between the two species reveal that the derived burrows of oldfield mice are dominant and evolved through the addition of multiple genetic changes. In burrows built by first-generation backcross mice, entrancetunnel length and the presence of an escape tunnel can be uncoupled, suggesting that these traits are modular. Quantitative trait locus analysis also indicates that tunnel length segregates as a complex trait, affected by at least three independent genetic regions, whereas the presence of an escape tunnel is associated with only a single locus. Together, these results suggest that complex behaviours—in this case, a classic ‘extended phenotype’ 4 —can evolve through multiple genetic changes each affecting distinct behaviour modules.

Wild rodents such as Peromyscus spp. are intermediate hosts for the zoonotic ascarid Baylisascaris procyonis (raccoon roundworm), and previous studies indicate Peromyscus leucopus (white-footed mouse) likely serves an important role in parasite ecology. Natural infections have been sporadically identified in a few Peromyscus spp., but no data are available on differences in susceptibility among the many other species. We compared survival and infection dynamics of B. procyonis in 4 species ( P. leucopus , Peromyscus maniculatus [deer mouse], Peromyscus californicus [California mouse], Peromyscus polionotus [Oldfield mouse]) from regions of varying habitat types as well as B. procyonis prevalence in raccoons. Six captive-bred mice of each species were inoculated per os with 1 of 3 biologically-relevant doses of embryonated B. procyonis eggs (∼10, ∼50, or ∼500). Animals were monitored twice daily for clinical signs and behavioral abnormalities and were euthanized at the onset of neurological signs or extensive (≥20%) weight loss, or at 45 days post-infection if no disease developed. Larvae were counted in the brain via microscopic examination and in skeletal muscle and visceral organs via artificial digestion. In the high-dose group, all but 1 mouse developed severe neurologic disease and were euthanized. In the medium-dose group, survival was variable and ranged from 33-85% across species. Little to no disease was observed in the low-dose group, although 1 P. maniculatus developed disease and was euthanized. Survival analysis reveals P. leucopus had a longer time until clinical disease onset versus the other species, which did not differ significantly from each other. Interestingly, larval recovery relative to dose was nearly identical across species and doses; however, larvae were differentially distributed in skeletal muscle, visceral organs, and brain among species. These data indicate that P. leucopus may be more resilient toward severe baylisascariasis compared to the other species and that even closely-related rodents may experience differential mortality. This variation in tolerance may have ecological implications for the different species as B. procyonis intermediate hosts, although more work is needed to put these experimental findings into context.

Gongylonema archboldi n. sp. (Nematoda: Gongylonematidae) is described from tunnels in the gastric mucosa of the stomach of the cotton rat (Sigmodon hispidus) from Highlands County, Florida, U.S.A. Measurements are also given for specimens from cotton mice (Peromyscus gossypinus), oldfield mice (Peromyscus polionotus), Florida mice (Podomys floridanus), and golden mice (Ochrotomys nuttalli) from the same locality. Additional specimens were collected from the cotton rat and the rice rat (Oryzomys palustris) from Berry Island, San Patricio County, Texas. The new species is differentiated from congeners by a combination of the following characters: length of the left spicule, length and shape of the gubernaculum, distribution of cuticular bosses, length of esophagus, and distance of the vulva from the posterior end. The status of the genus Gongylonema in North American rodents is reviewed. Fil: Kinsella J. M.. HelmWest Laboratory; Estados Unidos Fil: Robles, Maria del Rosario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; Argentina Fil: Preisser W.C.. Texas A&M University; Estados Unidos

Gongylonema archboldi n. sp. (Nematoda: Gongylonematidae) is described from tunnels in the gastric mucosa of the stomach of the cotton rat (Sigmodon hispidus) from Highlands County, Florida, U.S.A. Measurements are also given for specimens from cotton mice (Peromyscus gossypinus), oldfield mice (Peromyscus polionotus), Florida mice (Podomys floridanus), and golden mice (Ochrotomys nuttalli) from the same locality. Additional specimens were collected from the cotton rat and the rice rat (Oryzomys palustris) from Berry Island, San Patricio County, Texas. The new species is differentiated from congeners by a combination of the following characters: length of the left spicule, length and shape of the gubernaculum, distribution of cuticular bosses, length of esophagus, and distance of the vulva from the posterior end. The status of the genus Gongylonema in North American rodents is reviewed., Centro de Estudios Parasitológicos y de Vectores

Anthropogenic habitat loss is among the greatest threats to biodiversity. Populations undergoing fragmentation and loss of habitat are also threatened by erosion of genetic diversity. However, contemporary genetic diversity may be the legacy of natural processes acting prior to anthropogenic influences. Measurements of genetic diversity from contemporary and historical samples can evaluate the relative impact of natural and anthropogenic effects on its status. We investigated the genetic diversity of a threatened subspecies occupying Atlantic Coast barrier islands of Florida, Peromyscus polionotus niveiventris (southeastern beach mouse). To test for recent loss of genetic diversity, we compared cyt b data from museum samples (historical—prior to human impact) with contemporary samples throughout their range. Ten microsatellite loci were genotyped for samples from the contemporary range, to determine current population interconnectedness and structure. The results using cyt b data revealed no statistically significant loss of genetic diversity between historical and contemporary populations of P. p. niveiventris. Both nuclear and mitochondrial data support our conclusion that the observed capture and conservation of historical genetic diversity is explained by the large federally protected region of continuous habitat that remains with minimal human impact. Whereas, the two disjunct populations isolated by anthropogenic habitat destruction, exhibit significant losses of genetic diversity. Collectively, these findings offer a sound basis from which to formulate a conservation strategy to maintain the genetic diversity of P. p. niveiventris. Furthermore, our study underscores the importance of large expanses of continuous habitat within the geographic range of species to facilitate the maintenance of genetic integrity.

Measurements of size and asymmetry in morphology might provide early indications of damaging effects of inbreeding or other genetic changes in conservation breeding programs. We examined the effects of inbreeding on size and fluctuating asymmetry (FA) in skull and limb bone measurements in experimental populations of three subspecies of Peromyscus polionotus mice that had previously been shown to suffer significant reductions in reproductive success when inbred. Inbreeding caused significant depression in mean size in two of the subspecies (P. p. rhoadsi and P. p. subgriseus), but the effects were smaller in the third (P. p. leucocephalus). Inbreeding caused an increase in FA of just one of eight bilateral traits in one subspecies (P. p. rhoadsi). Inbreeding depression in size was more easily detected than the effects of inbreeding on FA. FA may be much less sensitive to inbreeding and other stresses than are more direct measures of fitness such as reproductive output and body mass growth rate. Given the large sample sizes and statistical complexity required to assess changes to typically very small levels of FA in captive populations, FA will not likely provide a useful measure of inbreeding depression in captive populations.

Track tubes may help measure impacts of disturbances on small mammals by providing information about the magnitude and timing of fluctuations in relative abundance. We evaluated live-capture and track-tube data from 8 trapping grids to test the utility of track tubes for monitoring abundance of beach mice (Peromyscus polionotus) through time and for comparing relative abundance of beach mice among sites. When averaged across grid sites, track indexes and abundance estimates exhibited strong covariation through time. Associations between the track index and estimated abundance on different grids varied from strong to very poor depending on sample period. Associations between track indexes and abundance estimates were strong when mouse densities on all grids were relatively low, but they were weak during other sample periods when densities were highly variable among grids. This study points to the need to understand factors that influence the relationship between indexes from track tubes and mouse abundance before track tubes can be used to compare abundances among sites.