Niviventer Fulvescens Research Articles

A new species of Podocinum Berlese (Acari: Podocinidae) and a key to species of the genus from China

Mites were collected from leaf litter and the fur of a wild rodent (Niviventer fulvescens ) in Guizhou Province of China, and described as Podocinum guizhouense sp. nov. (Podocinidae). This is the first report of Podocinidae from a wild rodent host, but this ecological association may be accidental. A key to the females of Podocinum from China is provided.

Chromosomal evolution in Rattini (Muridae, Rodentia)

The Rattini (Muridae, Murinae) includes the biologically important model species Rattus norvegicus (RNO) and represents a group of rodents that are of clinical, agricultural and epidemiological importance. We present a comparative molecular cytogenetic investigation of ten Rattini species representative of the genera Maxomys, Leopoldamys, Niviventer, Berylmys, Bandicota and Rattus using chromosome banding, cross-species painting (Zoo-fluorescent in situ hybridization or FISH) and BAC-FISH mapping. Our results show that these taxa are characterised by slow to moderate rates of chromosome evolution that contrasts with the extensive chromosome restructuring identified in most other murid rodents, particularly the mouse lineage. This extends to genomic features such as NOR location (for example, NORs on RNO 3 are present on the corresponding chromosomes in all species except Bandicota savilei and Niviventer fulvescens, and the NORs on RNO 10 are conserved in all Rattini with the exception of Rattus). The satellite I DNA family detected and characterised herein appears to be taxon (Rattus) specific, and of recent origin (consistent with a feedback model of satellite evolution). BAC-mapping using clones that span regions responsible for the morphological variability exhibited by RNO 1, 12 and 13 (acrocentric/submetacentric) and their orthologues in Rattus species, demonstrated that the differences are most likely due to pericentric inversions as exemplified by data on Rattus tanezumi. Chromosomal characters detected using R. norvegicus and Maxomys surifer whole chromosome painting probes were mapped to a consensus sequence-based phylogenetic tree thus allowing an objective assessment of ancestral states for the reconstruction of the putative Rattini ancestral karyotype. This is thought to have comprised 46 chromosomes that, with the exception of a single pair of metacentric autosomes, were acrocentric in morphology.

Differences in hoarding behaviors among six sympatric rodent species on seeds of oil tea ( Camellia oleifera) in Southwest China

Seed hoarding is an important behavioral adaptation to food shortages for many rodent species. Sympatric rodents may affect the natural regeneration of large-seeded trees differently as seed dispersers or seed predators. Using seeds of oil tea ( Camellia oleifera), we investigated differences in hoarding behaviors among six sympatric rodent species in semi-natural enclosures in a subtropical forest in southwest of China. We found that all these six species ate seeds of C. oleifera, but only Edward’s long-tailed rats ( Leopoldamys edwardsi) were predominantly scatter hoarders; chestnut rats ( Niviventer fulvescens) and white-bellied rats ( Niviventer confucianus) scatter hoarded and larder hoarded few seeds, but were seed predators; South China field mice ( Apodemus draco) exhibited little larder-hoarding behavior; and Chevrier’s field mice ( A. chevrieri) as well as Himalayan rats ( Rattus nitidusa) did not hoard seeds at all. The rodents that engaged in scatter hoarding often formed single-seed caches and tended to cache seeds under grass or shrubs. Our findings indicate that sympatric rodents consuming seeds of the same species of plant can have different hoarding strategies, affecting seed dispersal and plant regeneration differently. We conclude by discussing the role of these species in hoarding seeds of C. oleifera and highlight the essential role of Edward’s long-tailed rats as predominantly potential dispersers of this plant species.

New karyotypic data for Asian rodents (Rodentia, Muridae) with the first report of B‐chromosomes in the genus Mus

AbstractKaryotypes of 18 rodent species collected in various localities in Thailand were analysed as part of an epidemiological survey of the region using conventional cytogenetic techniques. The aim was to re‐assess the reliability of karyotype‐based diagnoses of Thai rodents using an updated taxonomic framework. The species examined include Menetes berdmorei (Sciuridae), Mus caroli, Mus cervicolor and Mus cookii, Hapalomys delacouri, Chiropodomys gliroides, as well as several representatives of most of the lineages of the Rattini tribe, that is Rattus exulans, Rattus losea, Rattus tanezumi, Leopoldamys edwardsi, Leopoldamys neilli, Maxomys surifer, Niviventer fulvescens, Berylmys berdmorei, Berylmys bowersi, Bandicota indica and Bandicota savilei (Muridae). The first descriptions of G‐ and/or C‐banding karyotypes are provided for several of these, that is, B. savilei, L. edwardsi, M. surifer, B. berdmorei, B. bowersi, N. fulvescens and H. delacouri. Although largely in agreement with available data, our findings on chromosome morphology differ slightly from those published for L. edwardsi, M. surifer, B. savilei and the two Berylmys species, B. berdmorei and B. bowersi. In addition, we document the novel finding of B‐chromosomes in the genera Berylmys, Bandicota and the emblematic Mus. Importantly, few species‐specific chromosomal characteristic could be identified within most of the genera investigated in our study and, in contrast to previous claims, the usefulness of karyotypes for diagnosing these Asian murid species appears to be limited.

Karyotypes of Three Rat Species (Mammalia: Rodentia: Muridae) from Hainan Island, China, and the Valid Specific Status of Niviventer lotipes

The karyotypes of three rat species from Hainan Island, China, were examined. Niviventer fulvescens (Gray, 1847) had 2n=46 and FN=64, similar to the karyotypes reported for N. fulvescens from Southeast Asia, while Niviventer lotipes () had 2n=52 and FN=66, which is distinct from the known karyotypes of other Niviventer species. Niviventer lotipes was recently considered conspecific with N. tenaster (), but the two were found to have extremely different karyotypes (2n=52 and FN=66 in N. lotipes; 2n=46 and FN=54 in N. tenaster). Therefore, in this paper N. lotipes is considered a valid species for the first time; it is distinct from N. tenaster and endemic to Hainan Island, where N. lotipes is differentiated from N. fulvescens by larger body and skull sizes, a shorter tail, and darker coloration. Rattus nitidus (Hodgson, 1845) from Hainan Island had 2n=42 and FN=62, which is similar to the reported karyotypes of conspecific populations in Southeast Asia.

Testing the high-tannin hypothesis with scatter-hoarding rodents: experimental and field evidence

With a combination of both experimental (caged, hours/daily) and field (free-ranging, several months) studies, we tested the high-tannin hypothesis that hoarding animals prefer to eat more low-tannin food items immediately but hoard more high-tannin items for later consumption. We studied two common rat species (Edward's long-tailed rat, Leopoldamys edwardsi; and chestnut rat, Niviventer fulvescens) and two nut species (Henry's chestnut, Castanea henryi; and cork oak, Quercus variabilis) that show varying tannin levels (0.6% versus 11.7%) but are similar in other traits. Based on the high-tannin hypothesis, we predicted that (1) both rat species would eat more low-tannin C. henryi nuts instantly but fewer high-tannin Q. variabilis nuts and (2) after harvesting a given nut, they would prefer to hoard more Q. variabilis nuts and fewer C. henryi nuts. The first prediction was firmly supported in our study: both rat species ate more C. henryi nuts than Q. variabilis nuts under all conditions. However, the second prediction was supported only in the field study, which lasted over several months, in contrast to the experiments conducted in seminatural enclosures (only 1 day). We found that high-tannin Q. variabilis nuts, in contrast to low-tannin C. henryi nuts, had a significantly higher probability of being hoarded and surviving as seedlings in the field. We conclude that experimental conditions used here are less likely to result in natural feeding preferences of tested animals and the high-tannin hypothesis is supported especially in the field setting.

A survey of small mammals from Huu Lien Nature Reserve, Lang Son Province, Vietnam

ABSTRACT A survey of the small mammals of Huu Lien Nature Reserve, Lang Son Province, Vietnam (21°40′52″N, 106°20′28″E) resulted in the capture of 187 specimens representing 21 species of bat, insectivore, and rodent: Suncus etruscus, Rhinolophus pearsonii, Rhinolophus pusillus, Rhinolophus stheno microglobosus, Aselliscus stoliczkanus, Hipposideros armiger, Hipposideros larvatus, Harpiocephalus harpia, Pipistrellus paterculus, Scotomanes ornatus, Callosciurus erythraeus, Dremomys rufigenis, Niviventer fulvescens, Niviventer langbianis, Tonkinomys daovantieni, Rattus andamanensis, Rattus losea, Rattus tanezumi, Mus caroli, Rhizomys pruinosus, and Atherurus macrourus. In addition Ratufa bicolor and Tamiops sp. are reported from observations. The recently described genus and species Tonkinomys daovantieni is currently known only from material collected during the present survey and is apparently endemic to karst habitats in northeastern Vietnam.

Fruit visitation patterns of small mammals on the forest floor in a tropical seasonal forest of Thailand

The fruit visitation patterns of small mammals were investigated by camera trappings on the forest floor in a tropical seasonal forest of Thailand. A total of 3,165 visits were recorded for seven small mammal species. The four Muridae species, Rattus remotus, Niviventer fulvescens, Leopoldamys sabanus and Maxomys surifer, all of which were nocturnal, were almost completely temporally segregated from the tree shrew, Tupaia belangeri, and the two squirrels, Callosciurus finlaysonii and Menetes berdmorei, which were diurnal or crepuscular. We suggest that the temporal segregation reduced the interference competition between the four Muridae species and the tree shrew or squirrel for fruits on the forest floor. In addition, the visitation patterns for fruit species differed among the four Muridae species and between the tree shrew and the two squirrels, suggesting that the variation in the visitation patterns for fruit species helped to facilitate coexistence among these species. In contrast, the two squirrels were similar in their visitation patterns, both temporally and in their choice of fruit species.

Mammal survey on Phu Quoc Island, southern Vietnam

An inventory of the mammal fauna of Phu Quoc Island, the largest offshore island of Vietnam lying 20 km off the Cambodian coast, has been conducted for the first time. A total of 17 species of small mammals were recorded: Cynopterus brachyotis, Cynopterus sphinx, Hipposideros ater, Rhinolophus shameli, Rhinolophus lepidus, Rhinolophus malayanus, Hesperoptenus blanfordi, Crocidura sp., Menetes berdmorei, Hylopetes alboniger, Berylmys berdmorei, Maxomys surifer, Rattus tanezumi, Rattus exulans, Niviventer fulvescens, Tupaia belangeri, Paradoxurus hermaphroditus. In addition, Pteropus vampirus, Callosciurus finlaysonii, Trachypithecus germani, Macaca fascicularis and Muntiacus muntjak were registered on the basis of field observations. Records for Sus scrofa and Cervus unicolor are based on interviews conducted. Most of the findings represent new distributional records for Vietnamese mammal fauna.

Records of murine rodents (Mammalia, Rodentia) in the Pleistocene localities of Tan Vinh and Ma U’Oi (Northern Vietnam) and their implications to past distribution

We describe two Vietnamese fossiliferous sites located in Hoà Binh province, northern Vietnam. The site of Tan Vinh, first described here, is a quarry opened in Triassic limestone which exposes a karstic network and its filling. One of the fissure filling contained 104 molars of Leopoldamys sabanus (Rodentia, Muridae). The biochronological age of these deposits can be estimated from late Middle Pleistocene to Holocene. The site of Ma U'Oi is a cave opened in a karstified limestone which yielded 56 molars of four species of Muridae in two assemblages: Niviventer andersoni, L. sabanus, Niviventer fulvescens among a mammal fauna dated from late Middle Pleistocene to Late Pleistocene, and L. sabanus, N. fulvescens and Hapalomys delacouri among a microvertebrate fauna dated to the late Middle Pleistocene. First, we present a description of the two sites in terms of sedimentology. Secondly, we compare molars dimensions of the most common murids, L. sabanus and N. fulvescens, recovered at Ma U'Oi and Tan Vinh, with those recovered in a Thai site. The size difference between the specimens of the two species, especially those of L. sabanus in great numbers, from the northern sites and those from the Thai site suggests a cline which can be due to latitudinal differences in palaeotemperatures. The occurrence of N. andersoni, L. sabanus, N. fulvescens in Pleistocene Vietnamese sites allow to update the past distribution of these species.

Rodent Diversity in a Highly Degraded Tropical Landscape: Hong Kong, South China

The diverse ecological roles played by different rodent species mean that the loss of some species and superabundance of others could potentially influence a wide range of ecological processes. Hong Kong (22° N, 114° E), with seven million people in a land area of 1100 km2, could be considered a `worst case scenario' for the survival of mammalian diversity. Existing information on rodents in Hong Kong was compiled from previous published and unpublished studies, and additional trapping was conducted at 17 non-urban sites. The rodent fauna of modern Hong Kong consists of eight species of rats and mice (Bandicota indica, Mus caroli, M. musculus, Niviventer fulvescens, Rattus norvegicus, R. rattus, R. tanezumi, R. sikkimensis: Muridae), one porcupine (Hystrix brachyura: Hystricidae), and one recently introduced tree squirrel (Callosciurus erythraeus: Sciuridae). Six of the murids are urban or agricultural commensals, so only the porcupine and two murids, N. fulvescens and R. sikkimensis, are likely survivors of Hong Kong's pre-deforestation native rodent fauna. The two murids co-dominate in forest and shrubland, but can also move through grassland, which has probably enabled their survival through repeated cycles of fragmentation and regrowth. Additional forest rodents that may have inhabited Hong Kong in the past are tentatively identified from information on their recent distributions in the region. One possible ecological consequence of Hong Kong's depleted rodent fauna is a shift in the balance between seed predation and seed dispersal, in favor of the former.

Seed consumption and caching on seeds of three sympatric tree species by four sympatric rodent species in a subtropical forest, China

Because it is difficult and often impossible to distinguish dispersal, consumption and caching of seeds among different rodent species in the field, the differences of sympatric rodent species in affecting seed fates and forest regeneration are often unknown. To understand the different impact of four sympatric rodent species on seed fates of three sympatric tree species, we studied the food-hoarding behavior of Edward's long-tailed rats ( Leopoldamys edwardsi), Chestnut rats ( Niviventer fulvescens), Himalayan rats ( Rattus nitidus) and Norway rats ( R. norvegicus) on seeds of three sympatric tree species: Cork oak ( Quercus variabilis), Serrate oak ( Q. serrata) and Oil tea ( Camellia oleifera) in a subtropical forest in the Dujiangyan Region, Sichuan Province, China. Consumption and caching of tagged seeds by rodents was measured in enclosures (10 m × 10 m) from September to December 2003. The results showed that Edward's long-tailed rats scatter-hoarded seeds of the three tree species. They scatter-hoarded Serrate oak significantly less than Cork oak (with large seed size) and Oil tea (with high energy). The transport distances of Serrate oak by all the four rodent species were significantly shorter than those of Cork oak and Oil tea. The cache sizes of the three seed species were all small. Most seeds were cached under grass or shrubs in the enclosure. In terms of the population abundance and food preference, Edward's long-tailed rats imposed most and the largest impact on seed fate of the three tree species. The results supported our hypothesis that sympatric rodent species may affect seed fate and forest regeneration differently. Only Edward's long-tailed rats might benefit the seed recruitment of Cork oak, Serrate oak and Oil tea, while the other three rodent species were purely seed-eater and thus might contribute little to seed regeneration of the three dominant tree species.

Ultrastructure of echimyid and murid rodent spines

AbstractAristiform spines of the rodents Niviventer fulvescens, Maxomys surifer, Hoplomys gymnurus and 17 species of Proechimys (representing both recognized subgenera and all nine species groups) were studied qualitatively using scanning electron microscopy (SEM) and quantitatively by measuring seven linear dimensions. SEM was used to examine spine tips, bases, longitudinal furrows and cross sections. Spines of the murid rodents N. fulvescens and M. surifer differed from those of the echimyid rodents H. gymnurus and Proechimys spp. in possessing a smaller base with a longer, narrower neck, scaled rather than ridged longitudinal furrows, and a solid internal core and large lacunae at the spine margins. Spines of H. gymnurus differed from those of Proechimys spp. in being considerably more robust with a stout neck at the base, an abruptly‐tapering tip and a dense inner layer with a series of smaller lacunae at the spine margins. A factor analysis of spine measurements revealed major differences among N. fulvescens, M. surifer, H. gymnurus, the Proechimys subgenus Trinomys and the nine Proechimys species groups within the subgenus Proechimys. However, all Proechimys species groups clustered closely together. A discriminant function analysis of the nine Proechimys species groups provided generally limited discriminatory power. Although spines are distinct at the generic and subgeneric levels, spines may possess limited diagnostic structure at the level of species within the subgenus Proechimys.

A survey of small mammals from Mt. Tay Con Linh II, Vietnam, with the description of a new species of Chodsigoa (Insectivora: Soricidae)

A survey of small mammals from Mt. Tay Con Linh II, Ha Giang Province, Vietnam (22°45'27N, 104°49'49E) resulted in the capture of 17 species of bat, insectivore, and rodent: Cynopterus sphinx, Rousettus leschenaulti, Sphaerias blanfordi, Scaptonyx fusicaudus, Chodsigoa parca, Chodsigoa caovansunga new species, Blarinella griselda, Crocidura attenuata, Crocidura fuliginosa, Crocidura wuchihensis, Belomys pearsonii, Callosciurus inornatus, Leopoldamys edwardsi, Niviventer fulvescens, Niviventer langbianis, Niviventer tenaster and Chiropodomys gliroides. In addition Ratufa bicolor and Tamiops sp. are reported from observations. Scaptonyx fusicaudus and Blarinella griselda represent new distributional records for Vietnam. As part of the process of identifying specimens of Vietnamese Chodsigoa, we examined specimens of C. lamula and C. parva, including the holotype of parva and concluded that C. parva is not synonymous with C. lamula but actually represents a separate, very small species currently known only from the type locality in Yunnan, China.

Structural Features of Spines in Some Rodents (Rodentia: Myomorpha, Hystricomorpha)

The architectonics of spines and hair was studied in Neacomys spinosus, Tokudaia osimensis, Arvicanthis somalicus, Leopoldamys sabanus, L. edwardsi, Maxomys moi, M. surifer, Niviventer fulvescens, N. confucianus, N. cremoriventer, Acomys cahirinus, A. somalica, Hystrix indica, H. cristata, Atherurus macrourus, Erethizon dorsatum, Proechimys steerei, and Lonchotrix emiliae. The presence of a dorsal longitudinal furrow covered by a modified cuticle is a common structural feature of spines in all studied species except E. dorsatum, H. indica, and H. cristata. The frontal surface of the mosaic (scales located side by side) and terrace cuticle (steps between scales) varies in different species from smooth to rib-folded. A terminology has been proposed to describe the main structures of spine and hair. The adaptive significance of the spine architectonics in rodents is discussed.

Richness, Abundance, and Habitat Relations of Rodents in the Lang Bian Mountains of Southern Viet Nam

We sampled rodents in the Lang Bian Mountains of southern Viet Nam in June 1997 (rainy season) and January 1998 (dry season) by live-trapping. Eight transects in pine ( Pinus ) savanna and primary forest were sampled for 10 consecutive nights. We captured 11 species of rodents, including 10 murids and one sciurid. Niviventer fulvescens was the most frequently-captured species and apparently was a habitat generalist. That species was captured in both pine savanna and primary forest, but a distinct shift in habitat use occurred between the two seasons. During the rainy season, individuals were captured frequently in both habitats, but during the dry season, N. fulvescens was restricted mostly to forest. Fluctuation in resource abundance was the most likely explanation for that habitat shift; enormous quantities of acorns were present in the dry season, but few resources were available in the rainy season. Other species of rodents were captured less frequently, and several species appeared to be more restricted in their habitat distributions than N. fulvescens .

Tree seed predation on degraded hillsides in Hong Kong

Hong Kong was once entirely covered in subtropical rain forest but almost all of this had been cleared by the 17th century. Today around 9% of the land area is covered by secondary forest, mostly developed since 1945, with an additional 5% under plantations, largely of exotic species. The use of mixed, native species for reforestation has only started recently. The aim of this study was to determine whether seed predation was a barrier to natural forest regeneration on degraded hillsides. Removal of seeds of eight tree species in the winter of 1995 and 12 in 1996 at four Hong Kong hillside sites was monitored. Seed removal at the two shrubland sites was higher than at the two grassland sites in both 1995 and 1996. Most seeds placed in the shrubland sites in 1996 were removed; 11 of 12 species were totally removed from one shrubland site within 60 days, while only one of 12 species was totally removed in one grassland site. Rats were found to be the major seed predator. They included Niviventer fulvescens and Rattus rattus flavipectus. The tough/thick coated seeds of Choerospondias axillaris and Elaeocarpus sylvestris had the lowest mean percentage removal. Currently, all reforestation efforts in Hong Kong use container-grown seedlings, which is expensive even on accessible sites and impractical in remote areas. The results of this study suggest that direct seeding may be possible if species with tough/thick coated seeds are used.