Nocturnal activity, foraging behavior and night-roost usage in Rhinolophus ferrumequinum nippon were examined using bat-detectors, radio transmitters and fluorescent tags. Emergence from the cave roost began around dusk from March to November. The mean emergence time averaged 14 min after sunset, and the principal foraging period was within a few hours after sunset. The main foraging style was flycatching (perch-hunting). The height of the branches used by bats as feeding or roosting sites averaged 4.1 m above the ground. The length of bat's stay per feeding site averaged 6.6 min. In June, August and September, once the bats emerged, they seldom returned to the cave until just before sunrise, but in July, lactating females returned to the cave before midnight. In November, most of the bats returned to the cave about two hrs after sunset. Home range of adult females averaged 1.5 ha, and they foraged mainly in open forests, woodland paths or forest edges. The distances traveled to their main foraging sites averaged 0.87 km. Maximum-recorded distance traveled was 2.3 km during one night, and they hunted up to a distance of 2.0 km from the cave. Bats used specific night roosts, and their roosting bouts in the night roosts extended for about six hrs in April and varied from one to five hrs in June and October.
The effects of intracerebroventricular infusion of histamine receptor antagonists on pulsatile secretion of luteinizing hormone (LH) were examined in ovariectomized, estradiol-primed rats under conditions of normal feeding or fasting for 48 h. Blood samples for determination of the plasma LH concentration by radioimmunoassay were collected every 6 min for 3 h through an atrial indwelling catheter. Ten microliters of either the H1 receptor antagonist chlorpheniramine (3 mM), the H2 receptor antagonist ranitidine (3 mM), or artificial cerebrospinal fluid (vehicle) were infused into the third ventricle during the second 1-h period of blood sampling. The infusion of either receptor antagonist failed to restore the pattern of pulsatile LH release in fasted animals to that observed in fed rats. The plasma LH concentration as well as the pulse frequency and pulse amplitude of LH secretion in fed rats were also not affected by either receptor antagonist. These results indicate that H1 or H2 receptor antagonists did not affect on tonic LH secretion in fed or fasted rats.
We developed a habitat suitability model for wild boar Sus scrofa in the Mt. Baekwoonsan region of Korea. We recorded wild boar field signs (dust baths, bedding sites, digging areas, feces and tracks) and habitat variables such as the nearest distance to watercourses (DWATER) and trails (DTRAIL), slope, aspect (ASPECT), forest type and forest age. Field signs and habitat characteristics were assessed within a 25 × 25 m quadrat along seven survey routes from August 1999 to July 2000. We conducted a CATMOD regression analysis based on 416 field signs at 50 points and classified them into 3 levels of habitat importance (high, medium and low) based on the relative importance of field signs. Habitat suitability indices (P) were calculated based on significant relationships between parameters such as DWATER, DTRAIL and ASPECT resulting in the following function: P = 1/(1 + exp (3.82 × (DWATER) 1.21 × (DTRAIL) + 1.35 × (ASPECT))). Important habitats of wild boar were distributed near watercourses and far from trails along east and south-facing slopes.
The present study examined the digestibility of eelgrass based on dry weight and energy by captive dugongs Dugong dugon in relation to the nutritional content of the eelgrass and the feeding parameters of the dugongs. Digestibility was calculated on the basis that food retention by captive dugongs is 144-168 hours. Digestibility of eelgrass was strongly affected by the lignin content of the eelgrass species concerned, with a negative correlation between the apparent digestibility of a species and its lignin content. Since fiber contents are higher in seagrasses, including eelgrasses, than in terrestrial plants on which mammalian herbivores typically feed, the apparent digestibility reported from captive dugongs in the present study indicate that eelgrass may have an extraordinarily high digestibility.
A survey of small mammals from Mt. Tay Con Linh II, Ha Giang Province, Vietnam (22°45'27"N, 104°49'49"E) 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, Crocidurawuchihensis, Belomys pearsonii, Callosciurus inornatus, Leopoldamysedwardsi, 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.
The Iriomote cat Prionailurus iriomotensis occurs only on Iriomote Island in the Ryukyu Archipelago of southern Japan. The population is estimated at 100 individuals and is on the decline. We examined resource overlap for prey and habitat between this species and introduced cats Felis catus by scat census and analysis of scat contents. The distribution of scats was completely different between the two species. The distribution of scats from Iriomote cats was associated with environmental factors such as vegetation types and terrain conditions, while the distribution of scats from feral cats mainly depended on locations of garbage dumps. Although the feral cat heavily utilized human rubbish, it also preyed upon thirteen species of native animals, ten of which were also used by Iriomote cats. From 1997 to 2001, the number of observed scats from Iriomote cats declined significantly, while feral cat scat became more common. Feral cats on Iriomote Island still depend on humans, but the expansion of their distribution into habitats of Iriomote cats may increase the competition for prey and habitat resources in the future.
The SRY (sex determining region on the Y chromosome) gene has an important role in sex determination and shows a strict paternal mode of inheritance. To better understand evolutionary changes in the gene structure and their phylogenetic utility, complete sequences of the SRY region (591-651 bp) spanning from the initiation codon (ATG) to the stop codon of TAG were determined in 20 cetacean species, covering two families of suborder Mysticeti and six families of suborder Odonticeti. The HMG (high mobility group) box (231 bp), a DNA binding motif, was highly conserved in the cetacean SRY sequences. In contrast, seven synonymous substitutions and 12 nonsynonymous substitutions were detected in the N-terminal region (156 bp). The C-terminal region was heterogeneous in length (216-261 bp). One base insertion at the end of the HMG box, which resulted in a frame-shift in the C-terminal region, was detected in superfamily Delphinoidea. Further sequence determination (171-175 bp) in the 5' flanking region of the SRY gene revealed the presence of an element of "GGGGGCGG", the consensus motif of Sp1 (specificity protein 1), in the predicted promoter region. Paternal lineage relationships inferred from these SRY sequences were concordant with previous phylogenetic inferences in the literature, using other gene markers.
We examined intraspecific genetic variation in the mitochondrial cytochrome b gene (1140 bp) in the Okinawa mouse, Mus caroli (Rodentia, Muridae), from Okinawa, Taiwan, Hainan, Yunnan (southern China), Thailand, Vietnam and Java, to better understand their evolutionary history and human impact on dispersal and colonization by the mice. Populations from each of the seven localities had distinctive mitochondrial DNA sequences. The genetic distances, ranging from 0.015 to 0.045 (0.033 on average), were comparable with inter-subspecies differences in the house mouse Mus musculus (0.024). Assuming that nucleotide substitutions occur at a constant rate of 0.024/million years/lineage for mitochondrial DNA, the divergence of in M. caroli is estimated to have occurred 0.3-0.9 million years ago. The relatively great extent of intraspecific mitochondrial DNA variation in this taxon, and the spatial mode of variation suggest that M. caroli is genetically structured in space, to a considerable extent. Our data imply that local insular populations of M. caroli have been separated for long evolutionary periods, and that the scattered distribution patterns in the insular domains are due to historical shrinkage of appropriate areas of habitat, rather than to recent establishment of dispersed local populations by inadvertent human introductions.