Neotoma Floridana Research Articles

Fleas (Siphonaptera) of the Allegheny Woodrat (Neotoma magister) in West Virginia with Comments on Host Specificity

Previous research has indicated fewer host-specific ectoparasites on woodrats of the eastern United States as compared to western woodrat species. The Allegheny woodrat (Neotoma magister) is a species of conservation concern that is associated with rocky habitats in the Appalachian and Interior Highland regions in the eastern United States. We examined Allegheny woodrat flea parasites in the core of the distribution to further elucidate patterns of ectoparasite host specificity in woodrats of the eastern United States. Of 346 fleas collected from 62 Allegheny woodrats, all but 1 were identified as Orchopeas pennsylvanicus. The single exception was a male Epitedia cavernicola, which represents only the second collection of this species from West Virginia. Unlike the eastern woodrat (Neotoma floridana), which hosts a variety of generalist flea parasites, Allegheny woodrats in our study were host to only 2 flea species, both of which are host specific to woodrats. We suggest that flea host specificity may be related to the specific habitat requirements of this species.

Range Extension of the Opossum (Didelphis virginiana) in the Chihuahuan Desert of Mexico

BALCOLM, B. J. 1994. Microhabitat and landscape characteristics associated with Allegheny woodrat (Neotoma magister) sites in Pennsylvania. Unpublished M.S. thesis, The Pennsylvania State University, University Park. BRITZKE, E. R. 1998. The distribution, status, and ecology of the eastern woodrat, Neotomafloridana, in Missouri. Unpublished M.S. thesis, Southwest Missouri State University, Springfield. CUDMORE, W. 1983. The distribution and ecology of the eastern woodrat, Neotoma floridana, in Indiana. Unpublished Ph.D. dissertation, Indiana State University, Terre Haute. FITCH, H. S., AND D. G. RAINEY. 1956. Ecological observations on the woodrat, Neotomafloridana. University of Kansas Publication, Museum of Natural History 8:501-533. HUMPHREY, S. R. 1988. Density estimates of endangered Key Largo woodrat and cotton mouse (Neotomafloridana smalli and Peromyscus gossypinus allapaticola), using the nested-grid approach. Journal of Mammalogy 69:524-531. KAzAcos, K. R., AND W. M. BOYCE. 1989. Baylisascaris larva migrans. Journal of the American Veterinary Association 195:894-903. MISSOURI DEPARTMENT OF CONSERVATION. 1997. Rare and endangered species of Missouri checklist. Missouri Department of Conservation, Jeffers n City, Missouri. MONTY, A-M. M., E. R. WAGLE, R. E. EMERSON, AND G. A. FELDHAMMER. 1995. Recently discovered populations of eastern woodrats (Neotoma floridana) in southern Illinois. Transactions of the Illinois State Academy of Science 88:43-47. NAWROT, J. R., AND W. D. KLIMSTRA. 1976. Present and past distribution of the endangered southern Illinois woodrat (Neotoma floridana illinoensis). Chicago Academy of Science, Natural History Miscellaneous 196:1-12.

Distribution of the Eastern Woodrat, Neotoma floridana, in Missouri

tional Register Program), Moody Foundation (Galveston), Center for Field Research (EARTHWATCH), City and County of Lubbock, West Texas Museum Association, Institute of Museum Research, the Museum of Texas Tech University, and the Lubbock Lake Landmark Community Volunteers. This study is part of the ongoing Lubbock Lake Landmark regional research program into late-Quaternary climatic and environmental change on the southern High Plains.

Multiplex PCR Identification of Eastern and Allegheny Woodrats in Zones of Contact

Two woodrat species, Neotoma magister and N. floridana haematoreia, are found in the Appalachian Moun- tain region of western North Carolina, eastern Tennessee, and northwestern Georgia, USA. Both are listed as either endangered or of special concern. Therefore, an accurate, nonlethal way to identify these 2 similar species is of particular interest. A multiplex polymerase chain reaction (PCR) method that quickly and accurately distin- guishes between N. magister and N. f haematoreia is described here. Using this method, we amplified a universal DNA fragment of 313 base pairs in reactions containing DNA template from either species, but only reactions con- taining DNA template from N. f haematoreia yielded an additional 237 base-pair nested fragment. This diagnostic test has been performed successfully on 61 woodrat samples. Limited trials indicated that it might also be used to distinguish between N. f illinoensis and Neotoma magister along zones of contact in northern Alabama, western Ten- nessee and Kentucky, and southern Illinois, USA. The availability of universal primers for the mammalian mito- chondrial control region makes the described development of species-specific primers and multiplex PCR an important method for distinguishing between other closely related mammalian taxa.

Prevalence of borrelia burgdorferi sensu lato infection among rodents and host-seeking ticks in South Carolina.

Tissues of rodents and host-seeking adult ticks collected in the Piedmont, Sandhills, Coastal Plain, and Coastal Zone of South Carolina were cultured in attempts to isolate Borrelia burgdorferi (Johnson, Schmid, Hyde, Steigerwalt & Brenner), the etiologic agent of Lyme disease. An exploratory, tree-based statistical analysis was used to identify ecological variables that were associated with spirochete infection among rodents and ticks. Spirochetes were isolated from tissues of 71 rodents: 22 (69%) of 32 eastern woodrats, 39 (53%) of 74 cotton mice, and 11(25%) of 44 hispid cotton rats. Rodent infection prevalences were significantly higher in the Coastal Zone than in other regions. Spirochetes were also cultured from 31 (2.6%) of 1,193 questing ticks. Prevalence of spirochetes in Ixodes affinis Neumann (19/74, 26%) was significantly higher than in I. scapularis Say (12/864, 1.3%) and other species (0/255) of ticks tested. In addition, two (9%) of 23 adult I. minor Neumann removed from woodrats contained spirochetes. Isolates from rodents and ticks were analyzed immunologically by indirect immunofluorescence and Western blots, and further characterized by polymerase chain reaction assays and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. All were determined to be B. burgdorferi sensu lato. Results of this study confirmed that B. burgdorferi is endemic in South Carolina, and that enzootic transmission cycles exist at foci in the Coastal Zone. These findings add additional evidence that I. affinis and I. minor are potentially significant maintenance vectors of the spirochete.

Host associations of ticks parasitizing rodents at Borrelia burgdorferi enzootic sites in South Carolina.

A total of 237 rodents was collected in 4 regions of South Carolina from July 1994 through December 1995. Eight species were collected, including cotton mouse, hispid cotton rat, eastern woodrat, marsh rice rat, white-footed mouse, eastern harvest mouse, golden mouse, and black rat. Of the 1,514 ticks recovered from these hosts, Ixodes minor Neumann, including larvae, nymphs, and adults, was the most abundant species, representing 54% of the total. Only immature stages of other tick species were found, including larvae and nymphs of Dermacentor variabilis (Say), Amblyomma maculatum Koch, Ixodes affinis Neumann, and Ixodes scapularis Say. All 5 tick species parasitized cotton mice, cotton rats, and woodrats, which were the most important small mammal hosts for ticks at the localities studied. Rice rats were hosts of A. maculatum, D. variabilis, and L. minor. Amblyomma maculatum was more strongly associated with cotton rats than other rodent species. Ixodes scapularis was most strongly associated with cotton mice, and I. minor was more strongly associated with both woodrats and cotton mice than other species of rodents. Ixodes minor parasitized hosts in the Coastal Zone only, where among spirochete-infected hosts, it was present in significantly greater numbers than other ticks. Furthermore, I. minor was the only tick species that showed a statistically significant positive association with spirochetal infection in rodents. More I. affinis parasitized spirochete-infected hosts than I. scapularis, but fewer than I. minor. The findings discussed herein provide evidence that implicates I. minor as the possible primary enzootic vector of the Lyme disease spirochete Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt and Brenner in the Coastal Zone of South Carolina. They also indicate that the high level of B. burgdorferi infection in rodents from this region may be a function of the combined involvement of I. minor, I. affinis, and I. scapularis in the enzootic transmission of the spirochete.

Genetic heterogeneity of Borrelia burgdorferi sensu lato in the southern United States based on restriction fragment length polymorphism and sequence analysis.

Fifty-six strains of Borrelia burgdorferi sensu lato, isolated from ticks and vertebrate animals in Missouri, South Carolina, Georgia, Florida, and Texas, were identified and characterized by PCR-restriction fragment length polymorphism (RFLP) analysis of rrf (5S)-rrl (23S) intergenic spacer amplicons. A total of 241 to 258 bp of intergenic spacers between tandemly duplicated rrf (5S) and rrl (23S) was amplified by PCR. MseI and DraI restriction fragment polymorphisms were used to analyze these strains. PCR-RFLP analysis results indicated that the strains represented at least three genospecies and 10 different restriction patterns. Most of the strains isolated from the tick Ixodes dentatus in Missouri and Georgia belonged to the genospecies Borrelia andersonii. Excluding the I. dentatus strains, most southern strains, isolated from the ticks Ixodes scapularis and Ixodes affinis, the cotton rat (Sigmodon hispidus), and cotton mouse (Peromyscus gossypinus) in Georgia and Florida, belonged to Borrelia burgdorferi sensu stricto. Seven strains, isolated from Ixodes minor, the wood rat (Neotoma floridana), the cotton rat, and the cotton mouse in South Carolina and Florida, belonged to Borrelia bissettii. Two strains, MI-8 from Florida and TXW-1 from Texas, exhibited MseI and DraI restriction patterns different from those of previously reported genospecies. Eight Missouri tick strains (MOK-3a group) had MseI patterns similar to that of B. andersonii reference strain 21038 but had a DraI restriction site in the spacer. Strain SCGT-8a had DraI restriction patterns identical to that of strain 25015 (B. bissettii) but differed from strain 25015 in its MseI restriction pattern. Strain AI-1 had the same DraI pattern as other southern strains in the B. bissettii genospecies but had a distinct MseI profile. The taxonomic status of these atypical strains needs to be further evaluated. To clarify the taxonomic positions of these atypical Borrelia strains, the complete sequences of rrf-rrl intergenic spacers from 20 southeastern and Missouri strains were determined. The evolutionary and phylogenetic relationships of these strains were compared with those of the described genospecies in the B. burgdorferi sensu lato species complex. The 20 strains clustered into five separate lineages on the basis of sequence analysis. MI-8 and TXW-1 appeared to belong to two different undescribed genospecies, although TXW-1 was closely related to Borrelia garinii. The MOK-3a group separated into a distinct deep branch in the B. andersonii lineage. PCR-RFLP analysis results and the results of sequence analyses of the rrf-rrl intergenic spacer confirm that greater genetic heterogeneity exists among B. burgdorferi sensu lato strains isolated from the southern United States than among strains isolated from the northern United States. The B. andersonii genospecies and its MOK-3a subgroup are associated with the I. dentatus-cottontail rabbit enzootic cycle, but I. scapularis was also found to harbor a strain of this genospecies. Strains that appear to be B. bissettii in our study were isolated from I. minor and the cotton mouse, cotton rat, and wood rat. The B. burgdorferi sensu stricto strains from the south are genetically and phenotypically similar to the B31 reference strain.

MOLECULAR PHYLOGENETICS OF THE NEOTOMA FLORIDANA SPECIES GROUP

Abstract Phylogenetic relationships among 4 subspecies of Neotoma floridana and sister species from the United States and Mexico were examined using DNA sequence data from the mitochondrial DNA cytochrome b gene. Parsimony, likelihood, and neighbor-joining analyses support the recognition of N. f. magister as a distinct species (N. magister). Populations of eastern woodrats from the southern and western United States also possessed relatively high levels of sequence divergence (5.3%), which may be indicative of ongoing divergence between these populations. These findings support conclusions from previous studies and add clarity to the biogeographic processes influencing evolution and diversification of this group of rodents.

Auditory cues support place navigation in rats when associated with a visual cue

Rats, like other crepuscular animals, have excellent auditory capacities and they discriminate well between different sounds [Heffner HE, Heffner RS, Hearing in two cricetid rodents: wood rats ( Neotoma floridana) and grasshopper mouse ( Onychomys leucogaster). J Comp Psychol 1985;99(3):275–88]. However, most experimental literature concerning spatial orientation almost exclusively emphasizes the use of visual landmarks [Cressant A, Muller RU, Poucet B. Failure of centrally placed objects to control the firing fields of hippocampal place cells. J Neurosci 1997;17(7):2531–42; and Goodridge JP, Taube JS. Preferential use of the landmark navigational system by head direction cells in rats. Behav Neurosci 1995;109(1):49–61]. To address the important issue of whether rats are able to achieve a place navigation task relative to auditory beacons, we designed a place learning task in the water maze. We controlled cue availability by conducting the experiment in total darkness. Three auditory cues did not allow place navigation whereas three visual cues in the same positions did support place navigation. One auditory beacon directly associated with the goal location did not support taxon navigation (a beacon strategy allowing the animal to find the goal just by swimming toward the cue). Replacing the auditory beacons by one single visual beacon did support taxon navigation. A multimodal configuration of two auditory cues and one visual cue allowed correct place navigation. The deletion of the two auditory or of the one visual cue did disrupt the spatial performance. Thus rats can combine information from different sensory modalities to achieve a place navigation task. In particular, auditory cues support place navigation when associated with a visual one.

Eastern Woodrat (Neotoma floridana) Consumption of Northern Bobwhite (Colinus virginianus)

The eastern woodrat (Neotoma floridana) is considered a generalist herbivore. Only anecdotal evidence suggests that eastern woodrats eat meat given the opportunity. We conducted trials to test whether the eastern woodrat would consume northern bobwhite (Colinus virginianus) under experimental conditions. We live trapped 27 eastern woodrats in the Flint Hills region of Kansas during Nov. and Dec. 1997. We assigned woodrats to either a control or one of two 108 h experimental treatments. We provided 9 control animals with laboratory rat chow ad libitum, 9 woodrats in treatment 1 with laboratory rat pellets ad lib. and a wild northern bobwhite carcass and 9 woodrats in treatment 2 with a bobwhite carcass only. Woodrats willingly consumed quail in both treatments. Control and treatment 1 woodrats maintained body mass, whereas animals in treatment 2 lost 17% of body mass. Consumption preferences changed temporally. Head and leg/feet of quail were consumed first, muscle second and organs last. We observed no difference in consumption preferences between treatments. We suggest the eastern woodrat may include meat in its food selection when seasonal food resources are limited.

Isolation, cultivation, and characterization of Borrelia burgdorferi from rodents and ticks in the Charleston area of South Carolina.

Twenty-eight Borrelia burgdorferi isolates from the Charleston, S.C., area are described. This represents the first report and characterization of the Lyme disease spirochete from that state. The isolates were obtained from December 1994 through December 1995 from the tick Ixodes scapularis, collected from vegetation, and from the rodents Peromyscus gossypinus (cotton mouse), Neotoma floridana (eastern wood rat), and Sigmodon hispidus (cotton rat). All isolates were screened immunologically by indirect immunofluorescence with monoclonal antibodies to B. burgdorferi-specific outer surface protein A (OspA) (antibodies H5332 and H3TS) and B. burgdorferi-specific OspB (antibodies H6831 and H614), a Borrelia (genus)-specific antiflagellin antibody (H9724), Borrelia hermsii-specific antibodies (H9826 and H4825), and two polyclonal antibodies (one to Borrelia species and another to B. burgdorferi). Six of the isolates were analyzed by exposing Western blots to monoclonal antibodies H5332, H3TS, H6831, and H9724. All isolates were also analyzed by PCR with five pairs of primers known to amplify selected DNA target sequences specifically reported to be present in the reference strain, B. burgdorferi B-31. The protein profiles of six of the isolates (two from ticks, one from a cotton mouse, two from wood rats, and one from a cotton rat) also were compared by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. We conclude that the 28 Charleston isolates are B. burgdorferi sensu stricto based on their similarities to the B. burgdorferi B-31 reference strain.

Changes in Cache Contents over Winter in Artificial Dens of the Eastern Woodrat (Neotoma floridana)

Artificial dens constructed for eastern woodrats ( Neotoma floridana ) were occupied readily by animals, and thus, their caches were available for repeated sampling over winter. Caches contained significantly fewer kilocalories in spring than in winter ( X ± SE , winter = 6,808.6 ± 637.08 kcal, spring = 2,556.8 ± 319.12 kcal). Male and female woodrats using artificial dens did not differ significantly in weight or in the kilocalories available in their caches in winter or spring. Additionally, woodrats did not change significantly in weight from autumn to spring, and the weights of individual woodrats were not correlated with the kilocalories available in their caches. Of the 17 different types of food found in the caches in artificial dens, seven (dicot leaves, Osage-orange seed, honey locust seed, bark on stored twigs and sticks, herbaceous plant material, red cedar leaves, and grass) were in five or more of the 12 dens. A few food items, such as Osage-orange seeds, were cached by all woodrats, but the variety of other items appeared to depend on availability of food sources within foraging ranges of individuals.

A new species of Orchopeas, Jordan, 1933 from the midwestern United States (Siphonaptera: Ceratophyllidae).

A new species of ceratophyllid flea, Orchopeas illinoiensis Lewis, n. sp., is described from the eastern woodrat, Neotoma floridana (Ord, 1818) collected in southwestern Illinois. Its diagnostic characters are illustrated, and an earlier collection record from Pulaski County, MO, is documented.

Influence of Maternal Diet and Perishability on Caching and Consumption Behavior of Juvenile Eastern Woodrats

We tested the hypotheses that juvenile eastern woodrats ( Neotoma floridana ) learned to select appropriate foods to cache by cues from the maternal diet and that the effect of perishability affected caching and consumption behavior of juvenile woodrats. In May 1993, female woodrats were mated and placed on a diet of garlic-flavored chow. Females in group A were fed garlic-flavored chow until offspring were weaned. Females in group B were fed garlic-flavored chow until parturition and then were placed on a diet of standard laboratory chow. All offspring were weaned at 45 days postpartum and maintained on a diet of standard laboratory chow. In October and November 1993, juveniles were tested to determine their preference for caching and consumption of garlic-flavored chow or a novel (mint) flavored chow. Juveniles in group A cached more garlic-flavored chow than juveniles in group B ( P = 0.04). There was no difference between groups in the amount of garlic chow consumed ( P = 0.5). Naive juveniles preferred to cache dry apple ( P = 0.01) but preferred to consume fresh apple ( P = 0.01). The outcome of our experiments suggests that maternal diet influences the cache-food selection of naive woodrats. Further, naive juvenile woodrats treat perishable and non-perishable foods in a manner similar to adults suggesting that their response to such foods is not learned.

Ectoparasite Fauna of the Eastern Woodrat, Neotoma floridana: Composition, Origin, and Comparison with Ectoparasite Faunas of Western Woodrat Species

We collected ectoparasites from eastern woodrats, Neotoma floridana, from 3 sites in the southeastern United States: coastal South Carolina, southeast Georgia, and south-central Georgia. Twelve ectoparasite species were recovered from 47 woodrats in South Carolina (5 ticks, 5 mites, 2 fleas), 13 from 35 woodrats in south-central Georgia (1 tick, 10 mites, 2 fleas), and 4 from a small host sample (7) in southeast Georgia (2 ticks, 1 mite, 1 flea). New state records are established for the listrophorid mite Listrophorus neotomae from both Georgia and South Carolina, the myocoptid mite Myocoptes neotomae from Georgia, and the ceratophyllid flea Orchopeas sexdentatus pennsylvanicus from South Carolina. Different ectoparasites predominated on woodrats at each site with the tick Ixodes minor being the most commonly collected species in South Carolina, the American dog tick Dermacentor variabilis in southeast Georgia, and the chigger Euschoengastia peromysci in south-central Georgia. Most of the 17 species recovered are known to parasitize several species of mammals, especially rodents, and none of them are host specific to N. floridana. However, the fleas Epitedia cavernicola and Epitedia neotomae are host-specific ectoparasites of eastern woodrats in other parts of their range. Also, 1 species of tick, 2 mites, and 3 fleas parasitize eastern woodrats in addition to western woodrats. A similar lack of host specificity is apparent for the few previously documented collections of ectoparasites from eastern woodrats, including 1 detailed survey in Indiana. Conversely, Neotoma spp. woodrats inhabiting western North America are parasitized by a plethora of host-specific ectoparasites including 2 tick species, 5 mites (other than chiggers), 20 chiggers, 2 sucking lice, and 42 fleas. Recognizing that western biotas are typically more speciose than corresponding eastern biotas in North America, we further propose that because eastern woodrats are the most recent and eastern descendants of the ancestral Neotoma stock, (1) some ectoparasite species failed to accompany the eastern woodrat lineage in its eastward dispersals, and (2) there has been insufficient time for a diverse assemblage of ectoparasites to co-evolve with eastern woodrats.

Consumption by Eastern Woodrats (Neotoma floridana) of Food Infected by Fungi

-Adult and juvenile eastern woodrats (Neotoma floridana) were given a choice between uninfected apple and apple at three (first trial) and two (second trial) different levels of fungal infection. During the first trial, woodrats preferred uninfected and highly infected apple over apple infected at medium levels of infection. During the second trial, the same woodrats continued to prefer to consume highly infected apples over apples at intermediate levels of infection. This preference was primarily a consequence of the large amounts of highly infected apple consumed by juvenile woodrats. Adult woodrats consumed nearly equal amounts of apples of all three groups. Results of this study suggest that vertebrates can and do consume biologically important amounts of fungally infected food, and sometimes prefer food at high rather than intermediate levels of moldiness. Results imply that foraging models that presume microbially infected foods are less valuable to food storing animals may need to be re-examined for the validity of those assumptions.

Effects of maternal nutrition on post-weaning growth in two North American rodents

The Trivers-Willard hypothesis of sex-biased maternal investment in response to fluctuations in resource availability has provided a theoretical foundation for research on maternal investment for more than two decades. Their hypothesis holds that mothers in poor condition as a result of poor resource availability should bias parental investment towards offspring with the highest probability of reproducing. In the polygynous mating system of mammals where males compete for breeding access to females, the hypothesis predicts investment favoring females. Although data from many systems have supported this hypothesis, other systems do not follow the predicted patterns and have resulted in various alternative hypotheses. The present research was designed to test whether differences in body condition of young reared by nutritionally stressed dams relative to young reared by unstressed dams were maintained into adulthood, one of the fundamental assumptions underlying the Trivers-Willard hypothesis. Post-weaning growth in eastern woodrats (Neotoma floridana) and northern grasshopper mice (Onychomys leucogaster) was examined relative to maternal nutritional plane. Individuals from undernourished dams were lighter than their unrestricted counterparts at weaning but no difference was evident by the time they had reached adult size. Failure to maintain body condition differences into adulthood violates one of the assumptions essential for application of the Trivers-Willard hypothesis of maternal investment patterns. Although the Trivers-Willard model proposed that natural selection favors differential investment in the sexes over the entire course of parental investment, evidence from this and other studies suggests that the Trivers-Willard hypothesis might not be appropriate to address maternal investment questions in postnatally malnourished dams, but instead should be restricted to systems concerned with prenatal maternal condition or resource availability.

Molecular Phylogeny of the Neotoma floridana Species Group

A phylogeny of the Neotoma floridana species group of woodrats was inferred using mi-tochondrial-DNA (mtDNA) restriction sites identified by 17 type-II restriction endonucleas-es. Wagner, Dollo, and generalized parsimony analyses revealed a sharp dichotomy among populations of Neotoma albigula found east and west of the Rio Grande. Additional polymorphism among samples of N. albigula from northern Mexico also was detected. Data from mtDNA suggest paraphyly exists within N. albigula and that at least two cryptic species are present within the taxon. Phylogenetic and phenetic analyses of the mtDNA data reveal a sister-group relationship between Neotoma micropus and N. albigula , whereas N. floridana and Neotoma magister form sister taxa to this group. These results clarify discrepancies reported for this species group based on morphologic, allozymic, and karyotype data. Additionally, Neotoma phenax, Neotoma cinerea, Neotoma mexicana , and Neotoma stephensi were included to provide an intrageneric perspective on relationships within the N. floridana species group. N. mexicana and N. stephensi formed a clade associated with the N. floridana species-group clade with N. phenax and N. cinerea appearing as sole members of branches basal to the remaining Neotoma .

Neotoma floridana floridana: Natural history, ecology, and movements in north-central Florida

A behavioral ecology study on the eastern woodrat (Neotoma floridana foridana) was conducted between September 1988 and February 1990 on the Katharine Ordway Preserve-Swisher Memorial Sanctuary. The Preserve is located in north-central Florida, approximately 5 miles east of Melrose. The goal of the study was to investigate factors that may influence density and distribution of Neotoma on the Ordway Preserve. Distribution of the eastern woodrat is closely associated with mesic hardwood hammocks on the Preserve. Five study sites were therefore selected in three habitat types: mesic hammock with open understory, mesic hammock with saw-palmetto understory, and bottomland hardwood swamp. Trapping along strip-transects at these sites demonstrated that the bottomland hardwood swamp consistently had the highest density of woodrats (4.3/ha at initiation of study). Densities fluctuated in all 5 study sites, and at Goose and Ashley lakes populations crashed. Radio telemetry was used to evaluate woodrat movements, habitat utilization, and den use. Woodrats were nocturnal with peaks in nighttime activity between 2000-2200 and 0100-0330 hours. Mean homerange size was larger in the mesic hammock with saw-palmetto understory (1.05 ha), which was least dense in horizontal woody growth. Home ranges were smaller in the mesic hammock with open understory (0.25 ha) and bottomland hardwood swamp (0.69 ha) which were more complex in horizontal and vertical vegetation structure. Home range size was positively correlated to number of dens used, which ranged from 1 to 3 dens in use at one time. Dens of woodrats were the center of all activity. Nest fidelity was high, but some individuals changed dens. Social tolerance was low, radiotelemetry and trapping observations rarely documented animals in close proximity to each other. In summary, the bottomland hardwood swamp, which has the highest stem density and vegetation cover supports the highest density ofwoodrats. These habitat features may influence smaller home ranges. The density fluctuations in all study sites and subsequent population crashes in two mesic hammock habitats, suggest woodrats may be influenced by external factors such as predation and drought conditions. Forests with less horizontal and vertical structural complexity may be marginal to woodrats due to cover requirements and food resource distribution. Populations inhabiting these environments may therefore be more vulnerable when heightened stress levels occur, such as changes in climatic conditions.

Home range, habitat use, and behavior of the eastern diamondback rattlesnake (Crotalus adamanteus) on the Ordway Preserve

The eastern diamondback rattlesnake (Crotalus adamanteus Beauvois) was studied by radio-telemetry from 3 September 1985 to 21 February 1989 at the Katharine Ordway Preserve/Carl S. Swisher Memorial Sanctuary, Putnam County, Florida. Five male and three female snakes were monitored for durations ranging from 33 days (11 observations) for a small female to 864 days (245 observations) for an adult male. Intervals between observations averaged 3.3 days. A total of 743 observations was used to determine home range, habitat use, movements and other behaviors for this species. Diamondback home ranges were analyzed using the McPAAI computer program (Smithsonian Institution). Females (n=2) maintained smaller home ranges (mean = 46.5 ha) than males (n=4, mean = 84.3 ha). The ranges of both males and females overlapped, indicating that this species is not territorial. Diamondback activity patterns suggest that they occupy stable home ranges that remain similar from year to year. Although rattlesnakes were recorded in all habitats available to them, the Swamp Forest/Mesic Hammocks and Xeric Hammocks were favored. They also utilized Wet Prairies during droughts. Eastern diamondbacks were almost entirely terrestrial, rarely climbing into trees (n=1) and infrequently going underground (n=35) during their activity season. During winter (Dec-Jan-Feb) rattlesnake movements decreased, but they remained on the surface 55.4% of the time. Burrows of armadillo (Dasypus novemcinctus, n=57) and gopher tortoise (Gopherus polyphemus, n=12), as well as root channels beneath stands of palmettos, were used as winter refugia. Mean monthly distances traveled increased during fall (Sep·Oct-Nov), when snake movements averaged over 20 m per day. At this time males made longer moves, probably searching f6r breeding females, whereas females made shorter movements. Movements were always made during daylight hours. The hunting strategy of C. adamanteus consisted of a sit-and-wait foraging behavior, with the main posture a tight coil from which it might ambush prey. Snakes spent anywhere from one day to almost a weekcoiled in the same hunting location. Necropsies of 14 rattlesnakes (from north-central Florida) that contained identifiable prey remains indicate that the cotton rat (Sigmodon hispidus, n=8) and the rabbit (probably Sylvilagus floridanus, n=5) are the numerically dominant prey; one sample included a white-footed mouse (probably Peromyscus gosopinus); other evidence identified the wood rat (Neotoma floridana) as prey for the eastern diamondback.