Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
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| rodents' responses to manipulated plant litter and seed densities: implications for restoration. | rodent populations in arid grasslands do not always track seed production, possibly due to high levels of plant litter. when natural disturbances are suppressed, litter accumulates becoming physically complex, causing rodents to harvest fewer seeds per equivalent time foraging. it also alters security from predation. restoring natural disturbances may be an important element in conserving rodent communities. the aim of this study was to assess the influence of two levels of plant litter cover an ... | 2020 | 32704449 |
| estimation of the force-velocity properties of individual muscles from measurement of the combined plantarflexor properties. | the force-velocity (f-v) properties of isolated muscles or muscle fibers have been well studied in humans and other animals. however, determining properties of individual muscles in vivo remains a challenge because muscles usually function within a synergistic group. modeling has been used to estimate the properties of an individual muscle from the experimental measurement of the muscle group properties. while this approach can be valuable, the models and the associated predictions are difficult ... | 2020 | 32680898 |
| effects of artificial light at night on the foraging behavior of an endangered nocturnal mammal. | modification of nighttime light levels by artificial illumination (artificial light at night; alan) is a rapidly increasing form of human disturbance that affects natural environments worldwide. light in natural environments influences a variety of physiological and ecological processes directly and indirectly and, as a result, the effects of light pollution on species, communities and ecosystems are emerging as significant. small prey species may be particularly susceptible to alan as it makes ... | 2020 | 32320890 |
| intercontinental test of constraint-breaking adaptations: testing behavioural plasticity in the face of a predator with novel hunting strategies. | constraint-breaking adaptations are evolutionary tools that provide a mechanism for incumbent-replacement between species filling similar ecological roles. in common-garden experiments, we exposed populations of two desert rodents to two different viper species, testing their ability to adjust to novel predators that use different hunting strategies. we aimed to understand whether both predators and prey with constraint-breaking adaptations actually manifest comparative advantage over their coun ... | 2020 | 32271948 |
| increasing the species diversity in the aspergillus section nidulantes: six novel species mainly from the indoor environment. | aspergillus section nidulantes encompasses almost 80 homothallic and anamorphic species, mostly isolated from soil, plant material, or the indoor environment. some species are clinically relevant or produce mycotoxins. this study reevaluated the species boundaries within several clades of section nidulantes. five data sets were assembled, each containing presumptive new species and their closest relatives, and phylogenetic and phenotypic analyses were performed. we tested the hypotheses that the ... | 2020 | 32074019 |
| established rodent community delays recovery of dominant competitor following experimental disturbance. | human activities alter processes that control local biodiversity, causing changes in the abundance and identity of species in ecosystems. however, restoring biodiversity to a previous state is rarely as simple as reintroducing lost species or restoring processes to their pre-disturbance state. theory suggests that established species can impede shifts in species composition via a variety of mechanisms, including direct interference, pre-empting resources or habitat alteration. these mechanisms c ... | 2019 | 31822258 |
| derived muscle arrangements and their shared innervation patterns of external and internal cheek pouches in rodents. | cheek pouches have evolved from the oral cavity in rodents and act as temporary food storage repositories. there are two types of opening, internal and external. details about the complex cutaneous muscles controlling the pouches have still not been fully elucidated. to understand the shared and derived traits of the muscles surrounding the cheek pouch and their innervation, we carried out an evolutionary morphological study using two desert kangaroo rats (dipodomys deserti) and three plains poc ... | 2020 | 31502343 |
| tendons from kangaroo rats are exceptionally strong and tough. | tendons must be able to withstand the forces generated by muscles and not fail. accordingly, a previous comparative analysis across species has shown that tendon strength (i.e., failure stress) increases for larger species. in addition, the elastic modulus increases proportionally to the strength, demonstrating that the two properties co-vary. however, some species may need specially adapted tendons to support high performance motor activities, such as sprinting and jumping. our objective was to ... | 2019 | 31160640 |
| the contributions of individual muscle-tendon units to the plantarflexor group force-length properties. | the combined force-length (f-l) properties of a muscle group acting synergistically at a joint are determined by several aspects of the f-l properties of the individual musculotendon units. namely, misalignment of the optimal lengths of the individual muscles will affect the group f-l properties. this misalignment, which we named [formula: see text], arises from the properties of the muscles (i.e., optimum fiber length and pennation angle) and of their tendons (i.e., compliance and slack length) ... | 2019 | 31111328 |
| inbreeding load and inbreeding depression estimated from lifetime reproductive success in a small, dispersal-limited population. | the fitness consequences of inbreeding and the individual behaviors that prevent its detrimental effects can be challenging to document in wild populations. here, we use field and molecular data from a 17-year study of banner-tailed kangaroo rats (dipodomys spectabilis) to quantify the relationship between inbreeding, mate kinship, and lifetime reproductive success. using a pedigree that was reconstructed using genetic and field data within a bayesian framework (median probability of parental as ... | 2019 | 30809076 |
| historical population size change and differentiation of relict populations of the endangered giant kangaroo rat. | from a conservation management perspective it is important to understand how genetic diversity is partitioned across a species' range, including 1) identification of evolutionarily distinct units versus those recently isolated through anthropogenic activities and 2) the relative genetic contributions among components of fragmented (meta)populations. to address these questions, we investigated the phylogeography and metapopulation structure among relict populations of the endangered giant kangaro ... | 2019 | 30715400 |
| functional connectivity and home range inferred at a microgeographic landscape genetics scale in a desert-dwelling rodent. | gene flow in animals is limited or facilitated by different features within the landscape matrix they inhabit. the landscape representation in landscape genetics (lg) is traditionally modeled as resistance surfaces (rs), where novel optimization approaches are needed for assigning resistance values that adequately avoid subjectivity. also, desert ecosystems and mammals are scarcely represented in lg studies. we addressed these issues by evaluating, at a microgeographic scale, the effect of lands ... | 2019 | 30680126 |
| efficacy and nontarget impact of zinc phosphide-coated cabbage as a ground squirrel management tool. | effective management of ground squirrels relies on an integrated pest management (ipm) approach. rodenticides may be included in an ipm program, but they must be efficacious with minimal impact on nontarget species. a zinc phosphide-coated green bait may meet these requirements. we established a study in northeastern california to test zinc phosphide-coated cabbage as a management tool for belding's ground squirrels (urocitellus beldingi). we specifically addressed factors that would influence t ... | 2019 | 30632260 |
| functional characterization of novel alox15 orthologs representing key steps in mammalian evolution supports the evolutionary hypothesis of reaction specificity. | arachidonic acid lipoxygenases (aloxs) are lipid-metabolizing enzymes that have been implicated in cell differentiation, but also in the pathogenesis of inflammatory, hyperproliferative and neurological diseases. most mammalian genomes involve six or seven functional alox genes and among the corresponding alox-isoforms the alox15 orthologs are somewhat unique since they exhibit variable reaction specificity using arachidonic acid as substrate. the evolutionary hypothesis of mammalian alox15 reac ... | 2019 | 30599203 |
| jumping mechanics of desert kangaroo rats. | kangaroo rats are small bipedal desert rodents that use erratic vertical jumps to escape predator strikes. in this study we examined how individual hind limb joints of desert kangaroo rats (dipodomys deserti) power vertical jumps across a range of heights. we hypothesized that increases in net work would be equally divided across hind limb joints with increases in jump height. to test this hypothesis, we used an inverse dynamics analysis to quantify the mechanical output from the hind limb joint ... | 2018 | 30420493 |
| uterine receptivity in merriam's kangaroo rat (dipodomys merriami). | the uterine surface undergoes significant remodeling, termed the "plasma membrane transformation," during pregnancy to allow for implantation of the blastocyst and formation of the placenta in viviparous amniote vertebrates. unlike other species within the superorder euarchontoglires, which have a hemochorial (highly invasive) placenta, kangaroo rats (dipodomys spp.) exhibit a less invasive endotheliochorial placenta. we characterized the changes that occur to membrane molecules and the cellular ... | 2018 | 30288962 |
| divergent behavior amid convergent evolution: a case of four desert rodents learning to respond to known and novel vipers. | desert communities world-wide are used as natural laboratories for the study of convergent evolution, yet inferences drawn from such studies are necessarily indirect. here, we brought desert organisms together (rodents and vipers) from two deserts (mojave and negev). both predators and prey in the mojave have adaptations that give them competitive advantage compared to their middle-eastern counterparts. heteromyid rodents of the mojave, kangaroo rats and pocket mice, have fur-lined cheek pouches ... | 2018 | 30125293 |
| divergent genetic mechanism leads to spiny hair in rodents. | spines, or modified hairs, have evolved multiple times in mammals, particularly in rodents. in this study, we investigated the evolution of spines in six rodent families. we first measured and compared the morphology and physical properties of hairs between paired spiny and non-spiny sister lineages. we found two distinct hair morphologies had evolved repeatedly in spiny rodents: hairs with a grooved cross-section and a second near cylindrical form. compared to the ancestral elliptical-shaped ha ... | 2018 | 30118524 |
| functional capacity of kangaroo rat hindlimbs: adaptations for locomotor performance. | many cursorial and large hopping species are extremely efficient locomotors with various morphological adaptations believed to reduce mechanical demand and improve movement efficiency, including elongated distal limb segments. however, despite having elongated limbs, small hoppers such as desert kangaroo rats (dipodomys deserti) are less efficient locomotors than their larger counterparts, which may be in part due to avoiding predators through explosive jumping movements. despite potentially con ... | 2018 | 29997260 |
| body mass-specific na+, k+-atpase activity in the medullary thick ascending limb - implications for species-dependent urine concentrating mechanisms. | in general, mammalian whole body mass-specific metabolic rate correlates positively with maximal urine concentration (umax) irrespective of whether or not the species have adapted to arid or mesic habitat. accordingly, we hypothesized that the thick ascending limb (tal) of a rodent with markedly higher whole body mass-specific metabolism than rat exhibits a substantially higher tal metabolic rate as estimated by na+, k+-atpase activity and na+, k+-atpase α1 gene and protein expression. the kanga ... | 2018 | 29351422 |
| bioinformatic analyses of zona pellucida genes in vertebrates and their expression in nile tilapia. | zona pellucida (zp) genes encode zp glycoproteins which constitute the coat surrounding oocytes and early embryos. genome-wide identification of zp genes is still lacking in vertebrates, especially in fish species. herein, we conducted bioinformatic analyses of the zp genes of the nile tilapia and other vertebrates. totally 16, 9, 17, 27, 21, 20, 26, 19, 14,11, 24, 17, 9, 18, 8, 11, 9, 8, 5, and 4 zp genes belonging to 5 subfamilies (zpa, zpb, zpc, zpd, and zpax) were found in the sea lamprey, e ... | 2018 | 29307115 |
| a multispecies test of source-sink indicators to prioritize habitat for declining populations. | for species at risk of decline or extinction in source-sink systems, sources are an obvious target for habitat protection actions. however, the way in which source habitats are identified and prioritized can reduce the effectiveness of conservation actions. although sources and sinks are conceptually defined using both demographic and movement criteria, simplifications are often required in systems with limited data. to assess the conservation outcomes of alternative source metrics and resulting ... | 2017 | 29193292 |
| vertical leaping mechanics of the lesser egyptian jerboa reveal specialization for maneuverability rather than elastic energy storage. | numerous historical descriptions of the lesser egyptian jerboa, jaculus jaculus, a small bipedal mammal with elongate hindlimbs, make special note of their extraordinary leaping ability. we observed jerboa locomotion in a laboratory setting and performed inverse dynamics analysis to understand how this small rodent generates such impressive leaps. we combined kinematic data from video, kinetic data from a force platform, and morphometric data from dissections to calculate the relative contributi ... | 2017 | 28680452 |
| population structure of dipodomys ingens (heteromyidae): the role of spatial heterogeneity in maintaining genetic diversity. | the giant kangaroo rat, dipodomys ingens (heteromyidae), is an endangered rodent that inhabits approximately 3% of its estimated historic range. its current distribution is centered in two geographic areas, situated about 150 km apart, in south-central california. we sequenced a 293 base-pair fragment at the 5' end of the control region in 95 giant kangaroo rats from nine localities to examine the genetic structure of extant populations. we determine that mutations in this section of the control ... | 1997 | 28565504 |
| dispersal and genetic structure in kangaroo rats. | we used spatial autocorrelation of allele frequencies to examine local structure in a population of bannertailed kangaroo rats for which wright's isolation-by-distance model seems applicable, and for which we can estimate neighborhood size based on 10 years of data on demography and dispersal. the uniform dispersion and strong philopatric tendencies of this species provide a test case for the idea that restricted dispersal can lead to local genetic structure in small mammals. whether we consider ... | 1991 | 28564057 |
| food caching and differential cache pilferage: a field study of coexistence of sympatric kangaroo rats and pocket mice. | ecologists studying sympatric heteromyid rodents have sought evidence for species differences in primary foraging abilities and preferences and/or behavioural responses to predation risk in order to explain coexistence. the present field study was conducted to test the hypothesis that another factor may be involved, namely differences in caching patterns, which may result in differences in vulnerability to pilferage. we examined differences between kangaroo rats (dipodomys merriami) and pocket m ... | 2001 | 28547403 |
| kangaroo rats revisited: re-evaluating a classic case of desert survival. | kangaroo rats are the archetypical organisms for mammalian survival in north american deserts, yet there are contradictions in the data surrounding their physiology and ecology. the traditional view has been that these nocturnal rodents have little tolerance to high temperatures (e.g., >30°c), reside in cool, humid burrows to escape the heat of the day, and nearly exclusively rely on a dry, carbohydrate-rich diet from which they metabolically derive most of their water supply. to test this view, ... | 2002 | 28466177 |
| species' traits help predict small mammal responses to habitat homogenization by an invasive grass. | invasive plants can negatively affect native species, however, the strength, direction, and shape of responses may vary depending on the type of habitat alteration and the natural history of native species. to prioritize conservation of vulnerable species, it is therefore critical to effectively predict species' responses to invasive plants, which may be facilitated by a framework based on species' traits. we studied the population and community responses of small mammals and changes in habitat ... | 2017 | 28317278 |
| effects of kangaroo rat exclusion on vegetation structure and plant species diversity in the chihuahuan desert. | long-term (1977-90) experimental exclusion of three species of kangaroo rats from study plots in the chihuahuan desert resulted in significant increases in abundance of a tall annual grass (aristida adscensionis) and a perennial bunch grass (eragrostis lehmanniana). this change in the vegetative cover affected use of these plots by several other rodent species and by foraging birds. the mechanism producing this change probably involves a combination of decreased soil disturbance and reduced pred ... | 1993 | 28313292 |
| structure in a desert rodent community: use of space around dipodomys spectabilis mounds. | in an earlier paper (bowers et al. 1987) we reported patterns of microhabitat use by desert rodents among 0.25-ha plots where seeds were added or certain rodent species removed. we used the results to make inferences about the spatial organization of the whole rodent community. here we change our focus to test for spatial usage patterns at a smaller (within-plot) scale. specifically, we examine to what extent spatial use varies with proximity to mounded burrows of the large kangaroo rat, dipodom ... | 1992 | 28313058 |
| the influence of seed apparency, nutrient content and chemical defenses on dietary preference in dipodomys ordii. | physical, nutritional and defensive qualities of seeds differ in the extent to which they influence granivore preference. in a study aimed to quantifying those differences, ord's kangaroo rats (dipodomys ordii) were found to prefer the seeds of just three of twenty-nine species: cryptantha crassisepala, oryzopsis hymenoides and salsola kali. oryzopsis hymenoides was most preferred during the early plant growth season (april-july); preference for s. kali peaked during late (august-november) and d ... | 1990 | 28312708 |
| the effects of owl predation on the foraging behavior of heteromyid rodents. | researchers have documented microhabitat partitioning among the heteromyid rodents of the deserts of north america that may result from microhabitat specific predation rates; large/bipedal species predominate in the open/risky microhabitat and small/quadrupedal species predominate in the bush/safer microhabitat. here, we provide direct experimental evidence on the role of predatory risk in affecting the foraging behavior of three species of heteromyid rodents: arizona pocket mouse (perognathus a ... | 1988 | 28312021 |
| competitive release in microhabitat use among coexisting desert rodents: a natural experiment. | competitive release among desert rodents on sand dunes of differing species richness was examined in the great basin and mohave deserts, usa. expansions in microhabitat use were exhibited by the kangaroo rats dipodomys ordii and d. merriami (granivorous heteromyid rodents, weighing 49 and 42 g, respectively) as the number of coexisting heteromyid species decreased geographically. perognathus longimembris, the only common small heteromyid species (7 g) exhibited no competitive release. this may b ... | 1986 | 28311364 |
| reingestion of feces in rodents and its daily rhythmicity. | the ingestion of feces is widespread among rodent species and is an extensively employed component of the repertoire of feeding behaviors in some species. coprophagy is thus a significant consideration in the nutrition and dietary ecology of many rodents. as certain fecal pellets pass from the anus, they are taken up directly into the mouth, chewed, and swallowed. the nocturnally active herbivorous kangaroo rat dipodomys microps ingests about 1/4 of the feces it produces daily and the daily patt ... | 1979 | 28310297 |
| the periodicity of daily activity and its seasonal changes in free-ranging and captive kangaroo rats. | populations ofdipodomys microps andd. merriami in eastern california (37°11'n. lat.) are active on the surface throughout the night and during the whole year. these two species, and the males and females within each species, show no significant differences in times of beginning or end of activity. beginning and end of nightly activity generally fall within the brighter part of the twilights, even though the total time spent on the surface by individuals is at times only an hour or two, or even l ... | 1976 | 28309330 |
| a mechanism for resource allocation among sympatric heteromyid rodent species. | laboratory feeding experiments were conducted with dipodomys ordii and perognathus flavus in an attempt to discover a mechanism which might result in seed size selection. there was no marked difference in the proportions of four seed types collected whether the rodents foraged in the presence or absence of one another. however, analysis of the variability in weight of each of the seed types collected by the two species showed that when alone, the larger kangaroo rat was less effective at harvest ... | 1978 | 28309270 |
| tactile discriminatory ability and foraging strategies in kangaroo rats and pocket mice (rodentia: heteromyidae). | a comparative study of seasonal food hoarding activity and tactile discriminatory ability in four species of heteromyid rodents (dipodomys panamintinus, d. merriami, perognathus longimembris, and p. formosus) was conducted in laboratory test arenas. animals were tested individually to determine their treatment of seed (white millet) and seed mimics (glass beads and gravel) offered as food. in general, all animals showed low levels of millet hoarding activity during winter months with higher leve ... | 1981 | 28309045 |
| perturbation analysis of competition and overlap in habitat utilization between dipodomys ordii and dipodomys merriami. | the populations of two coexisting species of dipodomys (heteromyidae, rodentia) were manipulated on 10, large, unenclosed, trapping grids. these manipulations revealed that, although many kangaroo rats are established residents in an area, a large number are transient individuals who quickly occupy vacated habitats. on plots from which residents had been removed, transients settled at rates of up to 5% of carrying capacity per day. these immigrants were invariably of the same species that was re ... | 1975 | 28308827 |
| adaptations for leaf eating in the great basin kangaroo rat, dipodomys microps. | dipodomys microps forages in saltbush (atriplex confertifolia), gathering the leaves into its external check pouches and returning them to the burrow to be cached or eaten. the leaves are available throughout the year and contain 50-80% water. d. microps can survive on these leaves in the laboratory without other food or water, but it is unusual among kangaroo rats in that it quickly succumbs when placed on a diet of air-dried seeds without water or succulent plant material. its mean urine conce ... | 1973 | 28308238 |
| influence of small-scale disturbances by kangaroo rats on chihuahuan desert ants. | banner-tailed kangaroo rats (dipodomys spectabilis) are prominent ecosystem engineers that build large mounds that influence the spatial structuring of fungi, plants, and some ground-dwelling animals. ants are diverse and functionally important components of arid ecosystems; some species are also ecosystem engineers. we investigated the effects of patch disturbances created by d. spectabilis mounds on ant assemblages in a chihuahuan desert grassland in southern new mexico by using pitfall traps ... | 2000 | 28308216 |
| mechanisms for the keystone status of kangaroo rats: graminivory rather than granivory? | graminivory by kangaroo rats (dipodomys spp.) was investigated as a potential mechanism for the keystone role of these rodents in the dynamics of desert grasslands. experiments confirmed that ord's kangaroo rats (dipodomys ordii) cut and consumed a large proportion of the tillers of three chihuahuan desert tussock-forming grass species. field observations indicated that the characteristically cut grass tillers were absent from all-rodent and medium-sized kangaroo rat exclosures, but were frequen ... | 1997 | 28308138 |
| effects of bannertail kangaroo rat mounds on small-scale plant community structure. | the effects of bannertail kangaroo rat (dipodomys spectabilis) mounds and associated soil-surface disturbance on plant species composition and diversity in the chihuahuan desert were examined with multivariate analysis. kangaroo rat mounds created disturbance gaps and contributed to local species diversity by creating microhabitats that supported unique plant communities. these microhabitats supported populations of species that were relatively rare in surrounding areas. the diversity observed a ... | 1996 | 28307650 |
| cheek pouch capacities and loading rates of heteromyid rodents. | rodents of the family heteromyidae are proficient gatherers and hoarders of seeds. a major component of their adaptive specialization for harvesting and transporting seeds is their spacious, fur-lined cheek pouches. precise measurements of cheek pouch capacities are essential if ecologists are to understand the foraging ecology, possible constraints on locomotion patterns, and competitive relationships of heteromyid rodents. to measure the size of these cheek pouches and the rate at which animal ... | 1997 | 28307290 |
| spatial population structure in the banner-tailed kangaroo rat, dipodomys spectabilis. | i attempted to characterize spatial units of local dynamics and dispersal in banner-tailed kangaroo rats (dipodomys spectabilis), to determine if spatial structure influenced population dynamics in the way predicted by current metapopulation models. d. spectabilis exhibited a hierarchical spatial structure. "local populations" that appeared as discrete entities on a scale of kilometers were subdivided into clusters of mounds on a scale of meters. this structure, however, cannot be characyerized ... | 1994 | 28307040 |
| the beaver's phylogenetic lineage illuminated by retroposon reads. | solving problematic phylogenetic relationships often requires high quality genome data. however, for many organisms such data are still not available. among rodents, the phylogenetic position of the beaver has always attracted special interest. the arrangement of the beaver's masseter (jaw-closer) muscle once suggested a strong affinity to some sciurid rodents (e.g., squirrels), placing them in the sciuromorpha suborder. modern molecular data, however, suggested a closer relationship of beaver t ... | 2017 | 28256552 |
| kangaroo rats change temperature when investigating rattlesnake predators. | predator presence causes acute stress in mammals. a prey animal's stress response increases its chance of survival during life-threatening situations through adaptive changes in behavior and physiology. some components of the physiological stress response can lead to changes in body surface temperatures. body temperature changes in prey could provide information about prey state to predators that sense heat, such as pit vipers. we determined whether wild rodents undergo a stress-induced change i ... | 2017 | 28188761 |
| rattlesnakes are extremely fast and variable when striking at kangaroo rats in nature: three-dimensional high-speed kinematics at night. | predation plays a central role in the lives of most organisms. predators must find and subdue prey to survive and reproduce, whereas prey must avoid predators to do the same. the resultant antagonistic coevolution often leads to extreme adaptations in both parties. few examples capture the imagination like a rapid strike from a venomous snake. however, almost nothing is known about strike performance of viperid snakes under natural conditions. we obtained high-speed (500 fps) three-dimensional v ... | 2017 | 28084400 |
| precipitation alters interactions in a grassland ecological community. | climate change is transforming precipitation regimes world-wide. changes in precipitation regimes are known to have powerful effects on plant productivity, but the consequences of these shifts for the dynamics of ecological communities are poorly understood. this knowledge gap hinders our ability to anticipate and mitigate the impacts of climate change on biodiversity. precipitation may affect fauna through direct effects on physiology, behaviour or demography, through plant-mediated indirect ef ... | 2017 | 27889916 |
| a mast-seeding desert shrub regulates population dynamics and behavior of its heteromyid dispersers. | granivorous rodent populations in deserts are primarily regulated through precipitation-driven resource pulses rather than pulses associated with mast-seeding, a pattern more common in mesic habitats. we studied heteromyid responses to mast-seeding in the desert shrub blackbrush (coleogyne ramosissima), a regionally dominant species in the mojave-great basin desert transition zone. in a 5-year study at arches national park, utah, usa, we quantified spatiotemporal variation in seed resources in m ... | 2016 | 27069574 |
| borrelia bissettiae sp. nov. and borrelia californiensis sp. nov. prevail in diverse enzootic transmission cycles. | two borrelia species, borrelia bissettiae sp. nov. and borrelia californiensis sp. nov., were first described by postic and co-workers (postic et al., 2007; postic et al., 1998) based on genetic analyses of several loci. multilocus sequence analysis (mlsa) of eight housekeeping loci confirmed that these two borrelia genospecies are distinct members of the b. burgdorferi s. l. complex (margos et al., 2010). b. bissettiae sp. nov. initially was described in transmission cycles involving neotoma fu ... | 2016 | 26813420 |
| rapid genetic restoration of a keystone species exhibiting delayed demographic response. | genetic founder effects are often expected when animals colonize restored habitat in fragmented landscapes, but empirical data on genetic responses to restoration are limited. we examined the genetic response of banner-tailed kangaroo rats (dipodomys spectabilis) to landscape-scale grassland restoration in the chihuahuan desert of new mexico, usa. dipodomys spectabilis is a grassland specialist and keystone species. at sites treated with herbicide to remove shrubs, colonization by d. spectabilis ... | 2015 | 26577599 |
| molecular survey of bartonella species and yersinia pestis in rodent fleas (siphonaptera) from chihuahua, mexico. | rodent fleas from northwestern chihuahua, mexico, were analyzed for the presence of bartonella and yersinia pestis. in total, 760 fleas belonging to 10 species were tested with multiplex polymerase chain reaction analysis targeting the glta (338-bp) and pla genes (478-bp) of bartonella and y. pestis, respectively. although none was positive for y. pestis, 307 fleas were infected with bartonella spp., resulting in an overall prevalence of 40.4%. a logistic regression analysis indicated that the p ... | 2016 | 26576933 |
| the complete mitochondrial genome of the dipodomys ordii (ord's kangaroo rat). | ord's kangaroo rat is a kangaroo rat native to western north america. in this study, we first reported the complete mitochondrial genome of dipodomys ordii that the first has the complete mitochondrial genome in the genus of heteromyidae. the mitogenome is a circular molecule of 16 257 bp in length, containing 13 protein-coding genes, 2 ribosomal rnas, 22 transfer rnas and a putative displacement loop region. all protein-coding genes started with a traditional atn codon and terminated with the m ... | 2016 | 26486753 |
| divergence in sink contributions to population persistence. | population sinks present unique conservation challenges. the loss of individuals in sinks can compromise persistence; but conversely, sinks can improve viability by improving connectivity and facilitating the recolonization of vacant sources. to assess the contribution of sinks to regional population persistence of declining populations, we simulated source-sink dynamics for 3 very different endangered species: black-capped vireos (vireo atricapilla) at fort hood, texas, ord's kangaroo rats (dip ... | 2015 | 26032147 |
| cacti supply limited nutrients to a desert rodent community. | in the sonoran desert, cacti represent a potentially important source of nutrients and water for consumers. columnar cacti, in particular, produce a large pulse of flowers and succulent fruit during hot summer months. the importance of cactus stems, flowers and fruit to the small mammal community has not been quantified. we exploited natural variation in the carbon isotope (δ(13)c) values of cacti (cam) versus c3 plants to quantify the relative use of these resources by a diverse desert small ma ... | 2015 | 25842296 |
| camels, cormorants, and kangaroo rats: integration and synthesis in organismal biology after world war ii. | during the decades following world war ii diverse groups of american biologists established a variety of distinctive approaches to organismal biology. rhetorically, organismal biology could be used defensively to distinguish established research traditions from perceived threats from newly emerging fields such as molecular biology. but, organismal biologists were also interested in integrating biological disciplines and using a focus on organisms to synthesize levels of organization from molecul ... | 2015 | 25592808 |
| genetic consequences of postglacial range expansion in two codistributed rodents (genus dipodomys) depend on ecology and genetic locus. | how does range expansion affect genetic diversity in species with different ecologies, and do different types of genetic markers lead to different conclusions? we addressed these questions by assessing the genetic consequences of postglacial range expansion using mitochondrial dna (mtdna) and nuclear restriction site-associated dna (rad) sequencing in two congeneric and codistributed rodents with different ecological characteristics: the desert kangaroo rat (dipodomys deserti), a sand specialist ... | 2015 | 25413968 |
| the neural code for auditory space depends on sound frequency and head size in an optimal manner. | a major cue to the location of a sound source is the interaural time difference (itd)-the difference in sound arrival time at the two ears. the neural representation of this auditory cue is unresolved. the classic model of itd coding, dominant for a half-century, posits that the distribution of best itds (the itd evoking a neuron's maximal response) is unimodal and largely within the range of itds permitted by head-size. this is often interpreted as a place code for source location. an alternati ... | 2014 | 25372405 |
| scaling of the spring in the leg during bouncing gaits of mammals. | trotting, bipedal running, and especially hopping have long been considered the principal bouncing gaits of legged animals. we use the radial-leg spring constant [formula: see text] to quantify the stiffness of the physical leg during bouncing gaits. the radial-leg is modeled as an extensible strut between the hip and the ground and [formula: see text] is determined from the force and deflection of this strut in each instance of stance. a hookean spring is modeled in-series with a linear actuato ... | 2014 | 25305189 |
| a multi-scale distribution model for non-equilibrium populations suggests resource limitation in an endangered rodent. | species distributions are known to be limited by biotic and abiotic factors at multiple temporal and spatial scales. species distribution models, however, frequently assume a population at equilibrium in both time and space. studies of habitat selection have repeatedly shown the difficulty of estimating resource selection if the scale or extent of analysis is incorrect. here, we present a multi-step approach to estimate the realized and potential distribution of the endangered giant kangaroo rat ... | 2014 | 25237807 |
| experimental field evidence of interspecific aggression between two species of kangaroo rat (dipodomys). | the competitive coexistence of heteromyid rodents has been primarily ascribed to differential utilization of resources such as microhabitats and seeds. an examination of the use of space by the kangaroo rat dipodomys merriami indicates this species is aggressively subordinate to a larger species, dipodomys spectabilis and is excluded from the larger species home range during the crtical fall harvesting season. these experiments suggest that interspecific aggression may be involved in the coexist ... | 1983 | 25024151 |
| natural selection and the genetic basis of osmoregulation in heteromyid rodents as revealed by rna-seq. | one adaptation of ecological and evolutionary interest is the extraordinary ability of desert rodents to retain water during waste production. much is known regarding the unique kidney physiology of kangaroo rats (dipodomys spp.) and their ability to retain water during waste production, yet the genetic basis of these physiological adaptations is relatively unknown. herein, we utilized rna-seq data to conduct a comparative study to identify osmoregulatory genes expressed in heteromyid rodents. w ... | 2014 | 24754676 |
| using imputation and mixture model approaches to integrate multi-state capture-recapture models with assignment information. | in this article, we first extend the superpopulation capture-recapture model to multiple states (locations or populations) for two age groups., wen et al., (2011; 2013) developed a new approach combining capture-recapture data with population assignment information to estimate the relative contributions of in situ births and immigrants to the growth of a single study population. here, we first generalize wen et al., (2011; 2013) approach to a system composed of multiple study populations (multi- ... | 2014 | 24571715 |
| genomics and museum specimens. | nearly 25 years ago, allan wilson and colleagues isolated dna sequences from museum specimens of kangaroo rats (dipodomys panamintinus) and compared these sequences with those from freshly collected animals (thomas et al. 1990). the museum specimens had been collected up to 78 years earlier, so the two samples provided a direct temporal comparison of patterns of genetic variation. this was not the first time dna sequences had been isolated from preserved material, but it was the first time it ha ... | 2013 | 24138088 |
| microsatellite analyses across three diverse vertebrate transcriptomes (acipenser fulvescens, ambystoma tigrinum, and dipodomys spectabilis). | historically, many population genetics studies have utilized microsatellite markers sampled at random from the genome and presumed to be selectively neutral. recent studies, however, have shown that microsatellites can occur in transcribed regions, where they are more likely to be under selection. in this study, we mined microsatellites from transcriptomes generated by 454-pyrosequencing for three vertebrate species: lake sturgeon (acipenser fulvescens), tiger salamander (ambystoma tigrinum), an ... | 2013 | 24099393 |
| fitness consequences of dispersal: is leaving home the best of a bad lot? | using 20 years of demographic and genetic data from four populations of banner-tailed kangaroo rats (dipodomys spectabilis), we asked whether dispersing individuals gain benefits during adulthood that might compensate for the substantial survival costs they experience as juveniles. compared to philopatric animals, within- and between-population dispersers gained no measureable advantages in adult survival, fecundity, or probability of recruiting offspring to adulthood. restricting analyses to me ... | 2013 | 23923492 |
| collision-based mechanics of bipedal hopping. | the muscle work required to sustain steady-speed locomotion depends largely upon the mechanical energy needed to redirect the centre of mass and the degree to which this energy can be stored and returned elastically. previous studies have found that large bipedal hoppers can elastically store and return a large fraction of the energy required to hop, whereas small bipedal hoppers can only elastically store and return a relatively small fraction. here, we consider the extent to which large and sm ... | 2013 | 23843217 |
| architecture of interstitial nodal spaces in the rodent renal inner medulla. | every collecting duct (cd) of the rat inner medulla is uniformly surrounded by about four abutting ascending vasa recta (avr) running parallel to it. one or two ascending thin limbs (atls) lie between and parallel to each abutting avr pair, opposite the cd. these structures form boundaries of axially running interstitial compartments. viewed in transverse sections, these compartments appear as four interstitial nodal spaces (inss) positioned symmetrically around each cd. the axially running comp ... | 2013 | 23825077 |
| permeability of roads to movement of scrubland lizards and small mammals. | a primary objective of road ecology is to understand and predict how roads affect connectivity of wildlife populations. road avoidance behavior can fragment populations, whereas lack of road avoidance can result in high mortality due to wildlife-vehicle collisions. many small animal species focus their activities to particular microhabitats within their larger habitat. we sought to assess how different types of roads affect the movement of small vertebrates and to explore whether responses to ro ... | 2013 | 23772966 |
| derivation of soil-screening thresholds to protect the chisel-toothed kangaroo rat from uranium mine waste in northern arizona. | chemical data from soil and weathered waste material samples collected from five uranium mines north of the grand canyon (three reclaimed, one mined but not reclaimed, and one never mined) were used in a screening-level risk analysis for the arizona chisel-toothed kangaroo rat (dipodomys microps leucotis); risks from radiation exposure were not evaluated. dietary toxicity reference values were used to estimate soil-screening thresholds presenting risk to kangaroo rats. sensitivity analyses indic ... | 2013 | 23604138 |
| the motilin gene evolved a new function in kangaroo rats and kangaroo mice (dipodomyinae). | the motilin receptor gene was lost in the ancestral lineage of rodents. subsequently, the gene encoding its ligand, motilin, has experienced different evolutionary fates. previous genomic analyses had shown that the motilin gene (mln) became a pseudogene independently in the lineages leading to the guinea pig and the common ancestor of the mouse and rat, yet an intact, and thus potentially functional, open reading frame for the mln was preserved in the dipodomys ordii genome. as only a single ml ... | 2012 | 23138633 |
| architecture of vasa recta in the renal inner medulla of the desert rodent dipodomys merriami: potential impact on the urine concentrating mechanism. | we hypothesize that the inner medulla of the kangaroo rat dipodomys merriami, a desert rodent that concentrates its urine to over 6,000 mosmol/kg h(2)o, provides unique examples of architectural features necessary for production of highly concentrated urine. to investigate this architecture, inner medullary vascular segments in the outer inner medulla were assessed with immunofluorescence and digital reconstructions from tissue sections. descending vasa recta (dvr) expressing the urea transporte ... | 2012 | 22914749 |
| a priori and a posteriori approaches for finding genes of evolutionary interest in non-model species: osmoregulatory genes in the kidney transcriptome of the desert rodent dipodomys spectabilis (banner-tailed kangaroo rat). | one common goal in evolutionary biology is the identification of genes underlying adaptive traits of evolutionary interest. recently next-generation sequencing techniques have greatly facilitated such evolutionary studies in species otherwise depauperate of genomic resources. kangaroo rats (dipodomys sp.) serve as exemplars of adaptation in that they inhabit extremely arid environments, yet require no drinking water because of ultra-efficient kidney function and osmoregulation. as a basis for id ... | 2012 | 22841684 |
| the roles of competition and environmental heterogeneity in the maintenance of behavioral variation and covariation. | many models of selection predict that populations will lose variation in traits that affect fitness. nonetheless, phenotypic variation is commonly observed in natural populations. we tested the influences of competition and spatial heterogeneity on behavioral variation within and among populations of merriam's kangaroo rats (dipodomys merriami) and tested for the differential expression of trait correlations. we found that populations of d. merriami exhibited more aggression at sites with more c ... | 2012 | 22834374 |
| positive interactions between desert granivores: localized facilitation of harvester ants by kangaroo rats. | facilitation, when one species enhances the environment or performance of another species, can be highly localized in space. while facilitation in plant communities has been intensely studied, the role of facilitation in shaping animal communities is less well understood. in the chihuahuan desert, both kangaroo rats and harvester ants depend on the abundant seeds of annual plants. kangaroo rats, however, are hypothesized to facilitate harvester ants through soil disturbance and selective seed pr ... | 2012 | 22348030 |
| architecture of kangaroo rat inner medulla: segmentation of descending thin limb of henle's loop. | we hypothesize that the inner medulla of the kangaroo rat dipodomys merriami, a desert rodent that concentrates its urine to over 6000 mosm/kg water, provides unique examples of architectural features necessary for production of highly concentrated urine. to investigate this architecture, inner medullary nephron segments in the initial 3000 μm below the outer medulla were assessed with digital reconstructions from physical tissue sections. descending thin limbs of henle (dtls), ascending thin li ... | 2012 | 22237592 |
| partitioning the effects of an ecosystem engineer: kangaroo rats control community structure via multiple pathways. | 1. ecosystem engineers impact communities by altering habitat conditions, but they can also have strong effects through consumptive, competitive and other non-engineering pathways. 2. engineering effects can lead to fundamentally different community dynamics than non-engineering effects, but the relative strengths of these interactions are seldom quantified. 3. we combined structural equation modelling and exclosure experiments to partition the effects of a keystone engineer, the giant kangaroo ... | 2011 | 22098534 |
| fitness costs of neighborhood disruption in translocations of a solitary mammal. | translocation is used to reestablish wild populations of animals, but translocation projects often do not meet their objectives because postrelease mortality of animals is high. one reason for translocation failure is that the behavioral or ecological requirements of released animals are unmet. maintaining founder-group social relationships during release can affect reestablishment of social species. solitary territorial species with stable neighbors (restricted dispersal and lifetime occupation ... | 2011 | 21978094 |
| Mechanisms of kin discrimination inferred from pedigrees and the spatial distribution of mates. | Where animals avoid inbreeding, different mechanisms of kin discrimination can leave different 'signatures' in the patterns of observed mate relationship. For example, consider a species with no paternal care. If a female avoids mating with familiar individuals, one would expect a deficit of offspring whose parents are maternal half-siblings, but paternal half-siblings would be unfamiliar with each other and thus have offspring at the frequency expected by chance. If spatial cues are used to avo ... | 2011 | 21883584 |
| Genetic diversity, recombination, and divergence in animal associated Penicillium dipodomyis. | Penicillium dipodomyis is thought to be an exclusively asexual fungus associated with Kangaroo Rats, Dipodomys species, and is unique among Penicillium species in growing at 37°C but producing no known toxins. Lack of recombination within P. dipodomyis would result in limited adaptive flexibility but possibly enhance local adaptation and host selection via maintenance of favourable genotypes. Here, analysis of DNA sequence data from five protein-coding genes shows that recombination occurs withi ... | 2011 | 21850241 |
| elevated surface temperature depresses survival of banner-tailed kangaroo rats: will climate change cook a desert icon? | modest increases in global temperature have been implicated in causing population extirpations and range shifts in taxa inhabiting colder environs and in ectotherms whose thermoregulation is more closely tied to environmental conditions. many arid-adapted endotherms already experience conditions at their physiological limits, so it is conceivable that they could be similarly affected by warming temperatures. we explored how climatic variables might influence the apparent survival of the banner-t ... | 2011 | 21833644 |
| on valuing patches: estimating contributions to metapopulation growth with reverse-time capture-recapture modelling. | metapopulation ecology has historically been rich in theory, yet analytical approaches for inferring demographic relationships among local populations have been few. we show how reverse-time multi-state capture-recapture models can be used to estimate the importance of local recruitment and interpopulation dispersal to metapopulation growth. we use 'contribution metrics' to infer demographic connectedness among eight local populations of banner-tailed kangaroo rats, to assess their demographic c ... | 2011 | 21697173 |
| how much can parentage analyses tell us about precapture dispersal? | estimating rates of movement among populations is never simple, and where young animals cannot all be captured at their birth sites, traditional field methods potentially underestimate dispersal rates. genetic assignment tests appear to hold promise for detecting 'precapture' dispersal, and recent evidence suggests that even on the scale of dispersal between populations, genetic parentage analyses can also be informative. herein, we examine the performance of both types of analysis with data fro ... | 2011 | 21255174 |
| augmenting superpopulation capture-recapture models with population assignment data. | summary ecologists applying capture-recapture models to animal populations sometimes have access to additional information about individuals' populations of origin (e.g., information about genetics, stable isotopes, etc.). tests that assign an individual's genotype to its most likely source population are increasingly used. here we show how to augment a superpopulation capture-recapture model with such information. we consider a single superpopulation model without age structure, and split each ... | 2010 | 21155745 |
| rapid response of a grassland ecosystem to an experimental manipulation of a keystone rodent and domestic livestock. | megaherbivores and small burrowing mammals commonly coexist and play important functional roles in grassland ecosystems worldwide. the interactive effects of these two functional groups of herbivores in shaping the structure and function of grassland ecosystems are poorly understood. in north america's central grasslands, domestic cattle (bos taurus) have supplanted bison (bison bison), and now coexist with prairie dogs (cynomys spp.), a keystone burrowing rodent. understanding the ecological re ... | 2010 | 21141180 |
| observations on the natural history of the fresno kangaroo rat. | 1946 | 20996663 | |
| thomas george lee - implantation and early development of north american rodents. | a century ago thomas g. lee amassed an unparalleled collection of developmental series of north american rodents such as the thirteen-lined ground squirrel, the plains pocket gopher and merriam's kangaroo rat. he was the first to describe the initial attachment of the squirrel blastocyst to the antimesometrial side of the uterus. the full potential of lee's material was not realized until after his death, when it came into the possession of mossman. the latter relied heavily on lee's collection ... | 2010 | 20947162 |
| wild rodents (dipodomys merriami) used as biomonitors in contaminated mining sites. | mining is one of the most important industrial activities globally; however, mining processes have critical environmental impacts, as mining is a major source of metals and metalloids that contribute significantly to the pollution of soil, sediment, water and air. heavy metals can impact the health of exposed human populations and nonhuman receptors. this study focused on arsenic because its genotoxicity is well-known. previously, we proposed a methodology to evaluate and integrate risk from a s ... | 2010 | 20390846 |
| biomechanics of locomotion in asian elephants. | elephants are the biggest living terrestrial animal, weighing up to five tons and measuring up to three metres at the withers. these exceptional dimensions provide certain advantages (e.g. the mass-specific energetic cost of locomotion is decreased) but also disadvantages (e.g. forces are proportional to body volume while supportive tissue strength depends on their cross-sectional area, which makes elephants relatively more fragile than smaller animals). in order to understand better how body si ... | 2010 | 20154184 |
| the antigenic relationship of the viruses of meningopneumonitis and lymphogranuloma venereum. | animals recovered from infection with the viruses of lymphogranuloma venereum, meningopneumonitis, and psittacosis, were reinoculated in crossimmunity tests with these viruses. in mice immunized by intracerebral or intranasal inoculation a reciprocal partial cross-immunity between the viruses of lymphogranuloma venereum and meningopneumonitis was demonstrated. in preliminary experiments, similar cross-immunity between the agents of lymphogranuloma venereum and psittacosis was not definitely demo ... | 1942 | 19871165 |
| stepwise loss of motilin and its specific receptor genes in rodents. | specific interactions among biomolecules drive virtually all cellular functions and underlie phenotypic complexity and diversity. biomolecules are not isolated particles, but are elements of integrated interaction networks, and play their roles through specific interactions. simultaneous emergence or loss of multiple interacting partners is unlikely. if one of the interacting partners is lost, then what are the evolutionary consequences for the retained partner? taking advantages of the availabi ... | 2010 | 19696113 |
| sin nombre virus and rodent species diversity: a test of the dilution and amplification hypotheses. | species diversity is proposed to greatly impact the prevalence of pathogens. two predominant hypotheses, the "dilution effect" and the "amplification effect", predict divergent outcomes with respect to the impact of species diversity. the dilution effect predicts that pathogen prevalence will be negatively correlated with increased species diversity, while the amplification effect predicts that pathogen prevalence will be positively correlated with diversity. for many host-pathogen systems, the ... | 2009 | 19649283 |
| the influence of density and sex on patterns of fine-scale genetic structure. | natal philopatry is expected to limit gene flow and give rise to fine-scale spatial genetic structure (sgs). the banner-tailed kangaroo rat (dipodomys spectabilis) is unusual among mammals because both sexes are philopatric. this provides an opportunity to study patterns of local sgs faced by philopatric and dispersing animals. we evaluated sgs using spatial genetic autocorrelation in two d. spectabilis populations (rucker and portal) over a 14-year temporal series that covered low, medium, and ... | 2009 | 19453729 |
| feeding preferences of the immature stages of three western north american ixodid ticks (acari) for avian, reptilian, or rodent hosts. | larval and nymphal ixodes pacificus cooley and kohls, i. (ixodes) jellisoni cooley and kohls, and dermacentor occidentalis marx were tested for host preference when simultaneously presented with a deer mouse (peromyscus maniculatus wagner), california kangaroo rat (dipodomys californicus merriam), western fence lizard (sceloporus occidentalis baird and girard), and california towhee (pipilo crissalis vigors) in an experimental apparatus. differences were observed in the preferences among the thr ... | 2009 | 19198525 |
| habits and economic relationships of the tulare kangaroo rat. | 1948 | 18906244 | |
| rictularia dipodomis n. sp. (nematoda; thelaziidae) from the kangaroo rat dipodomys sp. | 1948 | 18876868 | |
| characterization of expressed class ii mhc sequences in the banner-tailed kangaroo rat (dipodomys spectabilis) reveals multiple drb loci. | genes of the major histocompatibility complex (mhc) are exceptionally polymorphic due to the combined effects of natural and sexual selection. most research in wild populations has focused on the second exon of a single class ii locus (drb), but complete gene sequences can provide an illuminating backdrop for studies of intragenic selection, recombination, and organization. to this end, we characterized class ii loci in the banner-tailed kangaroo rat (dipodomys spectabilis). seven drb-like seque ... | 2008 | 18836711 |
| chihuahuan desert kangaroo rats: nonlinear effects of population dynamics, competition, and rainfall. | using long-term data on two kangaroo rats in the chihuahuan desert of north america, we fitted logistic models including the exogenous effects of seasonal rainfall patterns. our aim was to test the effects of intraspecific interactions and seasonal rainfall in explaining and predicting the numerical fluctuations of these two kangaroo rats. we found that logistic models fit both data sets quite well; dipodomys merriami showed lower maximum per capita growth rates than dipodomys ordii, and in both ... | 2008 | 18831180 |
| milk analysis of the kangaroo rat, dipodomys merriami. | the milk of dipodomys merriami has an average water content of 50.42 percent, which is low compared with milk from other mammals. the fat content is about 23.48 percent. the significance of these values is discussed in terms of the animal's water balance. | 1963 | 17842340 |
| ord kangaroo rat in captivity. | 1956 | 17810470 |