Neotoma Micropus Research Articles

Serological Response of Cats to Experimental Besnoitia darlingi and Besnoitia neotomofelis Infections and Prevalence of Antibodies to These Parasites in Cats from Virginia and Pennsylvania

Besnoitia darlingi and Besnoitia neotomofelis are cyst-forming tissue apicomplexan parasites that use domestic cats (Felis domesticus) as definitive hosts and opossums (Didelphis virginiana ) and Southern Plains woodrats (Neotoma micropus) as intermediate hosts, respectively. Nothing is known about the prevalence of B. darlingi or B. neotomofelis in cats from the United States. Besnoitia darlingi infections have been reported in naturally infected opossums from many states in the United States, and B. neotomofelis infections have been reported from Southern Plains woodrats from Texas, but naturally infected cats have not been identified. The present study examined the IgG antibody response of cats to experimental infection (B. darlingi n = 1 cat; B. neotomofelis n = 3 cats). Samples from these cats were used to develop an indirect immunofluorescent antibody test (IFAT), which was then used to examine seroprevalence of IgG antibodies to tachyzoites of B. darlingi and B. neotomofelis in a population of domestic cats from Virginia (N = 232 cats) and Pennsylvania (N = 209). The serum from cats inoculated with B. darlingi or B. neotomofelis cross-reacted with each other's tachyzoites. The titers to heterologous tachyzoites were 1 to 3 dilutions lower than to homologous tachyzoites. Sera from B. darlingi- or B. neotomofelis-infected cats did not react with tachyzoites of Toxoplasma gondii or Neospora caninum or merozoites of Sarcocystis neurona using the IFAT. Antibodies to B. darlingi were found in 14% and 2% of cats from Virginia and Pennsylvania, respectively. Antibodies to B. neotomofelis were found in 5% and 4% of cats from Virginia and Pennsylvania, respectively. Nine cats from Virginia and 1 cat from Pennsylvania were positive for both.

Besnoitia neotomofelisn. sp. (Protozoa: Apicomplexa) from the southern plains woodrat (Neotoma micropus)

Certain species of the protozoan genus Besnoitia cause clinical disease in livestock and wildlife. In the present paper a new species, Besnoitia neotomofelis is described from the southern planes woodrat (Neotoma micropus). The parasite was detected by bioassay of woodrat tissues in outbred Swiss Webster mice in an attempt to isolate Toxoplasma gondii. Initially, the organism was misdiagnosed as T. gondii because it was highly pathogenic for mice and its tachyzoites resembled T. gondii tachyzoites. Further studies revealed that it differed structurally and biologically from T. gondii. Tachyzoites were successfully cultivated and maintained in vitro in bovine monocytes and African green monkey kidney cells, and in vivo in mice. Non-dividing, uninucleate tachyzoites were approximately 1 x 5 μm in size. Longitudinally-cut bradyzoites in tissue sections measured 1.5-1.6 x 7.7-9.3 μm. Tissue cysts were microscopic, up to 210 μm long, and were infective orally to mice. Cats fed tissue cysts shed unsporulated 13 x 14 μm sized oocysts. All mice inoculated with B. neotomofelis died of acute besnoitiosis, irrespective of the dose, and Norwegian rats became infected but remained asymptomatic. Entero-epithelial stages (schizonts, gamonts) were found in cats fed tissue cysts. Large (up to 40 x 50 μm) first-generation schizonts developed in the lamina propria of the small intestine of cats. A second generation of small sized (8 μm) schizonts containing 4-8 merozoites was detected in enterocytes of the small intestine. Gamonts and oocysts were seen in goblet cells of the small intestinal epithelium. Tachyzoites were present in mesenteric lymph nodes of cats. Phylogenetic analysis indicated that B. neotomofelis was related to other Besnoitia species from rodents, rabbits, and opossums. Besnoitia neotomofelis is distinct from the 3 other species of Besnoitia, B. wallacei, B. darlingi and B. oryctofelisi that utilize cats as a definitive host.

Pack rats ( Neotoma spp.): Keystone ecological engineers?

The potential role of two species of pack rats ( Neotoma albigula and Neotoma micropus) as keystone ecological engineers was examined by estimating the species diversity of invertebrates living in the nest middens, and nitrogen mineralization rates in soils associated with the middens. Although pack-rat middens in tarbush ( Flourensia cernua) shrublands were smaller than those in creostebush ( Larrea tridentata) shrublands, they housed a higher abundance and diversity of arthropods. The Neotoma spp. middens were an important microhabitat for crickets ( Gryllus sp.), wolf spiders ( Lycosa spp.), and lycid beetle larvae (Lycidae) in all of the shrub habitats. There were five arthropod taxa that occupied all middens in the creosote-bush shrubland, and 12 arthropod taxa that occupied all middens in the tarbush shrubland. Soils associated with pack-rat middens had significantly higher soil organic-matter content than reference soils. Nitrogen mineralization was significantly higher in soils associated with pack-rat middens than in reference soils. Neotoma spp. create habitats with moderate microclimates that are essential for several invertebrates, thus contributing to maintenance of biodiversity. The effects of middens on soil organic matter and nitrogen mineralization create nutrient-rich patches. Neotoma spp. affect biodiversity and critical ecosystem processes, thus supporting the designation of keystone ecological engineers.

Comparative Digestion of Food Among Wildlife in Texas: Implications for Competition

Success in competition for a limited food resource can be determined in part by how efficiently a species digests food. We conducted in vivo trials to compare digestive performance by a guild of mast-consuming species in southern Texas: wild boar (Sus scrofa), white-tailed deer (Odocoileus virginianus), collared peccary (Pecari tajacu), wild turkey (Meleagris gallopavo), raccoon (Procyon lotor), and southern plains woodrat (Neotoma micropus). Four individuals of each species were fed commercial pellets and chromium-marked fiber to determine rates of passage. Dry matter and intake of digestible energy, and digestibility of detergent fiber, crude protein, and gross energy (metabolizability for turkeys) were determined for each species. Mean retention and time of passage of 95% of marked fiber were calculated. Digestibility and time of retention by wild boars was similar to foregut-fermenting species and equal to or greater than smaller hindgut fermenters. White-tailed deer and collared peccaries showed similar capabilities of digestion and retention, and also had higher digestibilities of fiber than small hindgut fermenters. Turkeys and raccoons had fast rates of passage and showed little digestion of fiber. Southern plains woodrats had intermediate digestibilities and times of retention. Wild boars are expected to be effective competitors for mast because of their digestive efficiency, large body size, and potential for consumption of large quantities of food.

Effects of Disturbance by Humans on Small Mammals in A Chihuahuan Desert Ecosystem

Abstract We investigated the impact of disturbance by humans on distribution of small mammals at the northeastern edge of the Chihuahuan Desert. We determined composition of small-mammal communities and characteristics of soil at water tanks, roadsides, and open range. Nitrogen and moisture in soil did not vary across sites, but compaction of soil, vegetational cover, and composition of small-mammal communities did vary. Small mammals were distributed as expected with the exception of four omnivores (Mus musculus, Neotoma micropus, Peromyscus leucopus, and P. maniculatus), which were at higher density on sites with high disturbance by humans and relatively low vegetational cover. Activity of humans may impact some small mammals by drawing them to areas that contain high levels of human-generated resources.

A Molecular Examination of Relatedness, Multiple Paternity, and Cohabitation of the Southern Plains Woodrat (Neotoma Micropus)

Two hundred twenty-two individuals of the southern plains woodrat (Neotoma micropus) were captured from 198 excavated middens at 10 discrete collecting sites from a single population in south-central Texas. Field data, mitochondrial D-loop haplotypes, and polymorphic microsatellite loci (5-7) were used to determine genetic patterns in parentage, relatedness, and mating strategy. Microsatellite loci were highly polymorphic (average observed heterozygosity = 0.859) and were used to construct genotypes that were unique for each individual (probability of identical genotypes: 1 in 2,104,567). Results indicated a high frequency of multiple paternity (6 of 9 litters), evidence of repeat mating between the same 2 individuals, and no indication of male dominance at any collection site. Examination of these data suggested a promiscuous mating system. Within a site, average relatedness between adult females was similar to that between adult males. A higher level of cohabitation from that previously documented was recorded and finer-scale analyses revealed high levels of relatedness between most cohabiting individuals. Taken with results from other studies of mating behaviors of N. micropus, our results suggest that mating and social behavior of this species are likely influenced by population density.

Using Museum Collections to Detect Pathogens

To the Editor: Natural history museum collections have evolved in recent years to meet the challenges of current and future interdisciplinary scientific studies. Many natural history museums have built tissue collections and made digital information (e.g., photographs, publications, geographic coordinates) freely available on the Internet. These collections provide endless opportunities to conduct studies, including temporal and spatial surveys of emerging and reemerging pathogens (1). We report an example of a museum collection being useful in detecting Trypanosoma cruzi, the etiologic agent of Chagas disease, in the southern plains woodrat (Neotoma micropus) in southern Texas. This finding is of interest in the epidemiology of Chagas disease because the climatic characteristics and demographics of the region are similar to areas in Latin America where Chagas disease is an important zoonotic agent that infects ≈20 million persons (2). Tissue samples from N. micropus woodrats archived in the Natural Science Research Laboratory at the Museum of Texas Tech University were evaluated for T. cruzi DNA by PCR methods. All samples were originally collected during March 2001–June 2003 from the Chaparral Wildlife Management Area in southern Texas (28o18′N, 99o24′W), 86 km west of the Mexico–US border; some samples had been used previously in other research projects (3). Individual rodents were captured with live traps (n = 13) or by excavating middens in which all the nest occupants were collected by hand (n = 146). Animals were later euthanized and tissue samples (heart, kidney, liver, lung, muscle, spleen) were obtained. Tissues were immediately frozen in liquid nitrogen and permanently stored in ultralow-temperature freezers. We extracted 1 DNA sample from each animal’s liver for use in this survey. DNA amplification was performed by using primers specific to T. cruzi (TCZ1 and TCZ2) (4) under previously standardized conditions and positive controls (5). T. cruzi DNA was detected in 42 (26.4%) of 159 woodrat samples tested. Males were infected significantly more often (31/82) than females (11/73); sex was not determined for 4 individuals (Score test for a binomial proportion, z = –4.0, p<0.01). Adults had a nonsignificant higher prevalence (24/92) than all other individuals in the remaining age categories combined (14/54) (age was not determined for 13 individuals) (Score test for a binomial proportion, z = –0.02, p = 0.98). Middens that harbored infected individuals (n = 28, mean = 1.8) were not significantly (t = 0.79, df = 84, p = 0.43) more populated than middens that harbored uninfected individuals (n = 58, mean = 1.6). Woodrats had been shown by using microscopy to be infected by T. cruzi and T. cruzi–like organisms (6); however, no definitive DNA-based confirmation had been performed (6,7). The results of this research confirm the infection of N. micropus woodrats with T. cruzi and show a higher prevalence than that reported in previous studies that used other diagnostic methods. These results also point to woodrats as a potentially important reservoir of T. cruzi in North America. We hypothesize that the high prevalence is a consequence of the nest-building habits of these rodents. These nests are complexes of dry branches, grasses, and leaves, with a mean diameter of 84 cm, and offer easy access and permanent refuge to triatomine bugs. Woodrats have been found in association with at least 5 triatomine species: Triatoma gerstaeckeri, T. lecticularia, T. neotomae, T. protracta, and T. sanguisuga (8). Another factor for consideration is woodrats’ multigenerational midden use, which may enable the permanent occurrence of triatomine colonies and therefore maintain long-term circulation of T. cruzi. Whereas recent characterizations of North American strains have included isolates from other mammalian reservoir hosts (9), the genotyping of parasites from N. micropus woodrats and other woodrats is still to be done. Despite successful results from tracking pathogens by using material deposited in natural history museum collections (10), this practice is not common. We suggest that natural history museum collections be used more frequently, especially for surveying and genotyping T. cruzi in mammals, because of the importance of such information in clarifying the epidemiology and the evolutionary history of this pathogen.

Bartonellaspp. andRickettsia felisin Fleas, Democratic Republic of Congo

<i>Bartonella</i>spp. and<i>Rickettsia felis</i>in Fleas, Democratic Republic of Congo

A longitudinal study of Bartonella infection in populations of woodrats and their fleas

Rodent-borne bartonellae have been identified as human pathogens. Little is known about Bartonella infections in woodrat hosts and their fleas and how woodrat-flea associations may affect the dynamics of Bartonella infections. We collected blood samples and fleas from two species of woodrats (Neotoma micropus and N. albigula) from Santa Fe County, NM, from 2002-2005. The most predominant flea species were Orchopeas sexdentatus and O. neotomae. Bartonella prevalence in woodrats was 64% overall, with a lower prevalence occurring in the pre-reproductive period compared to the early and late reproductive periods. A negative correlation between Bartonella prevalence in N. micropus and weight of N. micropus was observed. Flea load in Neotoma species was highest in the early reproductive period compared to the pre- and late reproductive periods and was higher in N. micropus compared to N. albigula. Bartonella prevalence in fleas was highest in the early reproductive period and lowest in the late reproductive period, and it was higher in fleas collected from N. micropus than in fleas collected from N. albigula. Abundance of O. sexdentatus was significantly higher in N. micropus compared to N. albigula, and abundance of O. sexdentatus and O. neotomae was highest in the early reproductive period. No direct correlations were found either between Bartonella prevalence in woodrats and in fleas or between Bartonella prevalence in woodrats and flea loads. Out of 25 partially characterized Bartonella isolates from Neotoma woodrats, 24 belonged to one genogroup based on sequencing of the gltA gene.

Catarina Virus, an Arenaviral Species Principally Associated with Neotoma micropus (Southern Plains Woodrat) in Texas

The purpose of this study was to define the taxonomic relationship of an arenavirus principally associated with the southern plains woodrat (Neotoma micropus) in southern Texas to other New World arenaviruses. The results of independent analyses of glycoprotein precursor amino acid sequences and nucleocapsid protein amino acid sequences indicated that the arenavirus in southern Texas is novel (proposed species name Catarina virus) and phylogenetically most closely related to Whitewater Arroyo virus, which is principally associated with the white-throated woodrat (Neotoma albigula) in northwestern New Mexico. Together, the close phylogenetic relationship between Catarina virus and Whitewater Arroyo virus and the association of these viral species with congeneric rodent species support the notion that the principal host relationships of some New World arenaviruses are a product of a long-term shared evolutionary relationship between the virus family Arenaviridae and the rodent family Cricetidae.

Molecular Evidence for High Levels of Intrapopulation Genetic Diversity in Woodrats (Neotoma micropus)

Nucleotide sequences from the mitochondrial control region and genotypes from 5 nuclear microsatellite loci were used to examine genetic structure and infer recent (within approximately the last 3,000 years) evolutionary history of a population (549 individuals) of the southern plains woodrat (Neotoma micropus). Observed heterozygosity values ranged from 0.61 to 0.89 across microsatellite loci and systematically were lower than expected heterozygosity values (0.66-0.95). Probability of unique identity using microsatellite data was high (1 individual in 66,005,424). Fifty-three mitochondrial haplotypes were obtained from 150 individuals. F(ST) values estimated from sequence and microsatellite data were 0.061 and 0.011, respectively, and the R(ST) for microsatellite data was 0.007. Within-group genetic variation ranged from 93.90% to 99.99% depending on whether sequence or microsatellite data were examined. Analyses of microsatellite data suggested that all sampled individuals belonged to a single population, albeit genetically diverse. However, combined data analyses suggested the presence of low levels of substructure attributable to maternal lineages within the population. Low nucleotide-diversity values (0.007-0.010) in addition to high haplotype-diversity values (0.915-0.933) indicate a high number of closely related haplotypes, and suggest that this population may have undergone a recent expansion. However, Fu's F(S) statistic did not fully support this finding, because it did not reveal a significant excess of recent mutations. A phylogenetic approach using the haplotype sequence data and a combined set including both haplotype and genotype data was used to test for evolutionary patterns and history.

Caching as a strategy for surviving periods of resource scarcity; a comparative study of two species of Neotoma

Summary Energy management has been studied in migrators and hibernators but little is know about energy management in cachers. We investigated the energy management behaviour of two species of cachers, Neotoma floridana and Neotoma micropus. We also investigated differences in energy management of these two species that experience different environmental conditions during the period of food scarcity. Results show that both species decrease body mass from autumn to winter and increase mass from winter to spring. Both species decrease body fat from autumn to winter but only N. floridana increases body fat from winter to spring. Plasma protein follows the same pattern as body mass in N. floridana. Plasma lipids decrease from autumn to winter but do not increase from winter to spring. Results indicate that cachers, unlike hibernators or migrators, are able to use the food cache to increase body mass and body fat when new resources are not being produced in the environment. Results suggest that environmental conditions alter resource management and the species that experiences more severe conditions stores more energy as fat.

The use of total body electrical conductivity (TOBEC) to predict lean and lipid mass in woodrats

Total body electrical conductivity (TOBEC) has become an increasingly employed method of estimating lean and lipid mass in small birds and mammals. The TOBEC value of an animal is highly correlated with lean mass. Prediction of lean mass with a linear regression equation allows for estimation of lipid mass by subtracting lean mass from total body mass (2-stage model). The accuracy of 2-stage models for predicting lipid mass has been questioned by previous investigators, who suggested that lipid mass was predicted more accurately directly from body mass and TOBEC (direct model). We examined the accuracy of TOBEC for predicting lipid mass in the eastern woodrat (Neotoma floridana) and southern plains woodrat (Neotoma micropus). Four 2-stage models, varying in the use of TOBEC as the independent or dependent variable and in the use of a transformed TOBEC value, were tested. Three direct models were tested in which lipid mass was predicted from TOBEC value or transformed TOBEC value and body mass. The direct models performed much better than 2-stage models in predicting lipid mass, with a relative error in predicted lipid mass of 80% less than the best 2-stage model. There was little difference in predictive error between 2-stage models that used TOBEC as the independent or dependent variable. The TOBEC value transformed for body geometry did not greatly improve either the 2-stage or direct models. Total body electrical conductivity showed potential in the prediction of lipid mass in woodrats and was the most accurate non-invasive method of determining lipid mass available.

Temporal and spatial distribution of Leishmania mexicana infections in a population of Neotoma micropus.

A 19-month mark-release-recapture study of Neotoma micropus with sequential screening for Leishmania mexicana was conducted in Bexar County, Texas, USA. The overall prevalence rate was 14.7% and the seasonal prevalence rates ranged from 3.8 to 26.7%. Nine incident cases were detected, giving an incidence rate of 15.5/100 rats/year. Follow-up of 101 individuals captured two or more times ranged from 14 to 462 days. Persistence of L. mexicana infections averaged 190 days and ranged from 104 to 379 days. Data on dispersal, density, dispersion, and weight are presented, and the role of N. micropus as a reservoir host for L. mexicana is discussed.

Vegetation Dynamics following Seasonal Fires in Mixed Mesquite/Acacia Savannas

Fires were once a natural part of most savanna ecosystems, but lack of fine fuel and an active suppression policy have changed fire frequency and seasonality. Re-introducing fires to these systems has been touted as a cost-effective means to reduce woody cover while increasing herbaceous growth. We compared the effects of single, recurring annual, and biennial fires on the vegetation dynamics of a mixed mesquite/acacia (Prosopis/Acacia) savanna in southern Texas. Fires were conducted either during the growing season or the dormant season from 1991 through 1995. Some of the fire treatments were statistically unreplicated to permit a sufficient plot size for natural fire behavior. All plots showed a successional trajectory from short-grasses towards mid-grasses regardless of the fire season or frequency. The population size structure of perennial grasses was unaffected by the fires, with the basal area of most plants being less than 25 cm2. Forb diversity was high with over 100 different species identified in the experimental area. Forb composition, however, was unaffected by either the season or frequency of fire, but was related to the year of observation. Shrubs in this community typically sprout after disturbance, so little mortality was expected. The only observed mortality was of small shrubs or saplings (diameter < 3 cm) and of large trees which had woodrat (Neotoma micropus) nests at the base. Reintroducing growing season fires into mesquite/mixed acacia shrublands did not conclusively alter plant community composition. Burning during the growing season when environmental conditions were hotter and drier did not accelerate succession toward grass-dominated communities. DOI:10.2458/azu_jrm_v55i5_owens

Natural host relationships and genetic diversity of Whitewater Arroyo virus in southern Texas.

The purpose of this study was to refine our knowledge of the natural host relationships of Whitewater Arroyo (WWA) virus. Two hundred eight rodents, representing nine species, were captured in July 1999 on the Chaparral Wildlife Management Area in southern Texas and tested for evidence of arenavirus infection. Antibody to an arenavirus was found in seven (21.9%) of 32 southern plains woodrats (Neotoma micropus) and none of 168 other rodents. Infectious WWA virus was isolated from four antibody-positive southern plains woodrats, one of 25 antibody-negative southern plains woodrats, and none of 176 other rodents. Collectively, the results indicate that the southern plains woodrat is a principal host of WWA virus in southern Texas. Analyses of viral gene sequence data revealed substantial genetic diversity among WWA virus strains isolated from the woodrats, suggesting that multiple variants of the virus can coexist in a single woodrat species in a small geographic area.

Demographics, Den Use, Movements, and Absence of Leishmania mexicana in Southern Plains Woodrats (Neotoma micropus)

Southern plains woodrats (Neotoma micropus; n = 180) from 86 dens were trapped, tagged, and screened for Leishmania during 2,292 trap-nights conducted at the La Copita Research Area in southern Texas from May 1997 throughDecember 1998. None tested positive for Leishmania. Data on longevity, natality, sex ratio, and density of woodrats at this locality are presented along with an analysis of the changing occupancies of individual dens and apparent movements between dens by individual woodrats.

Vegetation dynamics following seasonal fires in mixed mesquite/acacia savannas

Fires were once a natural part of most savanna ecosystems, but lack of fine fuel and an active suppression policy have changed fire frequency and seasonality. Re-introducing fires to these systems has been touted as a cost-effective means to reduce woody cover while increasing herbaceous growth. We compared the effects of single, recurring annual, and biennial fires on the vegetation dynamics of a mixed mesquite/acacia (Prosopis/Acacia) savanna in southern Texas. Fires were conducted either during the growing season or the dormant season from 1991 through 1995. Some of the fire treatments were statistically unreplicated to permit a sufficient plot size for natural fire behavior. All plots showed a successional trajectory from short-grasses towards mid-grasses regardless of the fire season or frequency. The population size structure of perennial grasses was unaffected by the fires, with the basal area of most plants being less than 25 cm2. Forb diversity was high with over 100 different species identified in the experimental area. Forb composition, however, was unaffected by either the season or frequency of fire, but was related to the year of observation. Shrubs in this community typically sprout after disturbance, so little mortality was expected. The only observed mortality was of small shrubs or saplings (diameter &lt; 3 cm) and of large trees which had woodrat (Neotoma micropus) nests at the base. Reintroducing growing season fires into mesquite/mixed acacia shrublands did not conclusively alter plant community composition. Burning during the growing season when environmental conditions were hotter and drier did not accelerate succession toward grass-dominated communities.

The detection of hemorrhagic proteins in snake venoms using monoclonal antibodies against virginia opossum ( Didelphis virginiana) serum

Most snakes and a few warm-blooded animals have a resistance to snake venoms because of naturally occuring antihemorrhagins found in their sera. The antihemorrhagins in serum of Virginia opossum ( Didelphis virginiana) neutralize hemorrhagic activity by binding to hemorrhagins in snake venoms. The binding characteristic of antihemorrhagins in D. virginiana serum was used to develop a five-step western blot. The detection of hemorrhagic proteins were measured indirectly with antihemorrhagins in Virginia opossum serum and with DV-2LD#2, a monoclonal antibody specific for Virginia opossum antihemorrhagins. Snake venoms were separated by native-PAGE, transferred to a Millipore Immobilon™-P membrane and then incubated with crude Virginia opossum serum. The hemorrhagins in snake venom bind to antihemorrhagins in Virginia opossum serum which react with DV-2LD#2 a monoclonal antibody that is specific for Virginia opossum antihemorrhagins. DV-2LD#2 monoclonal antibody inhibits antihemorrhagic activity in Virginia opossum serum when mixed in equal amounts. The inhibition of antihemorrhagins by DV-2LD#2 monoclonal antibody suggests specificity. DV-2LD#2 monoclonal antibody does not recognize antihemorrhagins in gray woodrat ( Neotoma micropus) serum. The five-step western blot reveals two well-defined bands which represent hemorrhagins found in Western diamondback rattlesnake ( Crotalus atrox) venom. Venoms from 15 different snake species were examined to determine the usefulness of the five-step western blot. Other hemorrhagic venoms (Great Basin rattlesnake ( C. viridis lutosus), Prairie rattlesnake ( C. viridis viridis), Tancitaran dusky rattlesnake ( C. pusillus), Northern Mojave rattlesnake ( C. scutulatus scutulatus type B) and Northern Pacific rattlesnake ( C. v. oreganus)) had one single band in the five-step western blot. DV-2LD#2 did not bind to the non-hemorrhagic venoms and reacted with 50% of the hemorrhagic venoms used in this study. The monoclonal antibody, CAH, reacted with all the hemorrhagic venoms except for the venom of the King cobra ( Ophiophagus hannah) and did not react with the non-hemorrhagic venoms. The hemorrhagic binding site of CAH monoclonal antibody and the antihemorrhagin in Virginia opossum are different binding sites. The five-step western blot will be a very useful assay for determining hemorrhagic activity without using live animals.

Spines protect plants against browsing by small climbing mammals.

The presence of spines on woody plants has been shown to limit the loss of foliage to large mammalian browsers by restricting both bite size and biting rate. We tested the hypothesis that plant spines are also an effective defense against browsing by small mammals, such as rodents, that climb within the canopy of shrubs to harvest fruits, seeds, and foliage. Tame southern plains woodrats (Neotoma micropus) were allowed to harvest raisins impaled on the branches of blackbrush shrubs (Acacia rigidula Benth.) in five categories of spinescence: naturally spineless, moderately spiny, or very spiny branches, and moderately spiny and very spiny branches with the spines removed. Plant spinescence significantly reduced the woodrats foraging efficiency (P = 0.0001). Although plant spines are generally thought to be an evolved defense against browsing by ungulate herbivores, they may also reduce browsing by small mammals.