A new rhabditoid nematode species in Asian sciurids, distinct from Strongyloides robustus in North American sciurids

Strongyloides callosciureus n. sp. (Nematoda: Rhabditoidea), from Asian sciurids, is described based on morphology, morphometry, and the small and large subunit (SSU/LSU) ribosomal RNA gene (rDNA) sequences. This new species was collected from Pallas's squirrels (Callosciurus erythraeus) in the central part of mainland Japan (Honshu), which were originally introduced from Taiwan some decades ago, and plantain squirrels (Callosciurus notatus) imported from Malaysia as personal pets. For comparison, Strongyloides robustus Chandler, 1942 was collected from American red squirrels (Tamiasciurus hudsonicus) and southern flying squirrels (Glaucomys volans) imported from the United States as personal pets. The parasitic females found in North American and Asian sciurids shared some key morphological features such as the ovary running spirally around the gut, and the shapes of the stoma in the apical view and the tail. However, morphometric features of parasitic females in North American and Asian sciurids differed significantly from each other; the former was larger than the latter, and the relative position of the vulva to the whole body length from the mouth was different. The SSU/LSU rDNA sequences supported the division of sciurid Strongyloides isolates by geographical distribution of the host and morphological features, leading us to propose the erection of new species.     

Survey for zoonotic rickettsial pathogens in northern flying squirrels, Glaucomys sabrinus, in California

Epidemic typhus, caused by Rickettsia prowazekii, is maintained in a southern flying squirrel (Glaucomys volans) sylvatic cycle in the southeastern United States. The northern flying squirrel (Glaucomys sabrinus) has not been previously associated with R. prowazekii transmission. A second rickettsial pathogen, Anaplasma phagocytophilum, infects dusky-footed woodrats (Neotoma fuscipes) and tree squirrels in northern California. Because northern flying squirrels or their ectoparasites have not been tested for these rickettsial pathogens, serology and polymerase chain reaction (PCR) were used to test 24 northern flying squirrels for R. prowazekii and A. phagocytophilum infection or antibodies. Although there was no evidence of exposure to R. prowazekii, we provide molecular evidence of A. phagocytophilum infection in one flying squirrel; two flying squirrels also were seropositive for this pathogen. Fleas and ticks removed from the squirrels included Ceratophyllus ciliatus mononis, Opisodasys vesperalis, Ixodes hearlei, Ixodes pacificus, and Dermacentor paramapertus.     

Murine and epidemic typhus rickettsiae: how close is their relationship?

Typhus fever has occurred globally as epidemic and endemic disorders. In 1910, Brill reported a typhus-like illness which Zinsser and others determined to be recurrent epidemic typhus fever. Maxcy, in 1926, proposed rodents and fleas as reservoir and vector, respectively, of endemic typhus, which Dyer confirmed in 1930. Animals experimentally infected with epidemic typhus (Rickettsia prowazeki) are immune to murine typhus (Rickettsia typhi) and vice versa. Similar solid cross-immunity exists for humans. The two diseases are clinically similar in pathologic and serologic reactions. Human epidemic typhus presumably involved a man-louse-man cycle without an animal reservoir. This concept is now questioned. Antibodies to R. prowazeki have been reported in livestock in Africa, rats in Manila, and from flying squirrels and humans in the United States. R. prowazeki was recovered from blood specimens of goats, sheep, from ixodid ticks, louse, and flea-ectoparasites of flying squirrels, and tissues of flying squirrels. More than 20 cases of squirrel-related acute epidemic typhus have been reported in the United States. R. prowazeki has not been recovered from human cases. Chemical studies of R. prowazeki and R. typhi show genetic similarities but differences in genome size and degree of hybridization suggest that interconversions between the two agents do not occur rapidly in nature. It is proposed that, with time, their relatedness will become even closer.     

Flying squirrels and their ectoparasites: disseminators of epidemic typhus

Information gathered during the past decade indicates that the eastern flying squirrel, Glaucomys volans, is a zoonotic reservoir of Rickettsia prowazekii - causative agent of louse-borne (epidemic) typhus. The sporadic cases o f typhus that have occurred in the USA in association with flying squirrels provide evidence that flying squirrels can transmit R. prowazekii infection to humons. Strains of R. prowazekii, isolated from flying squirrels multiply readily in human body lice, but flying squirrel lice, although readily infected, are very host specific and tend not to bite humans. It may be that the infection is spread to humans in infective ectoporasite faeces aerosolized when the flying squirrels groom themselves. As Joseph McDade emphasizes in this article, current concepts of typhus epidemiology and control must be re-evaluated to take into account this zoonotic aspect.     

Space invaders: effects of invasive alien Pallas’s squirrel on home range and body mass of native red squirrel

Alien species can affect native species through several ecological processes such as competition. Here we tested the hypothesis of interspecific competition for space and food resources between the native Eurasian red squirrel and the invasive Pallas’s squirrel introduced in Italy. We used an experimental study design comparing space and habitat use and body condition parameters of red squirrels between areas of co-occurrence with the Pallas’s squirrel and areas without it. There were no differences in mean home range size of red squirrels between red-only areas and red-Pallas. However, when Pallas’s squirrels were removed, the red squirrels increased their home ranges. Moreover, in the area of syntopy, red squirrels had a higher degree of intraspecific home range overlap than in the red-only area. We also found indirect evidence for competition for food with red squirrels having a poorer body condition when co-occurring with the alien species. We analyzed the body mass and size of red squirrels in the two areas and our results showed that red squirrels had a reduced body mass and size when in syntopy, confirming that the interspecific competition does not allow red squirrels to reach the optimum body condition that they would have if the competitor was not present. Moreover, tree-species niche overlap was very high and both species fed primarily on the same tree seeds. Differences in vegetation cover between areas are discussed. This is the first study that confirms the invasiveness of the Pallas’s squirrel also in terms of capability to compete with native species.     

Donning your enemy's cloak: ground squirrels exploit rattlesnake scent to reduce predation risk

Ground squirrels (Spermophilus spp.) have evolved a battery of defences against the rattlesnakes (Crotalus spp.) that have preyed on them for millions of years. The distinctive behavioural reactions by these squirrels to rattlesnakes have recently been shown to include self-application of rattlesnake scent-squirrels apply scent by vigorously licking their fur after chewing on shed rattlesnake skins. Here, we present evidence that this behaviour is a novel antipredator defence founded on exploitation of a foreign scent. We tested three functional hypotheses for snake scent application--antipredator, conspecific deterrence and ectoparasite defence--by examining reactions to rattlesnake scent by rattlesnakes, ground squirrels and ectoparasites (fleas). Rattlesnakes were more attracted to ground squirrel scent than to ground squirrel scent mixed with rattlesnake scent or rattlesnake scent alone. However, ground squirrel behaviour and flea host choice were not affected by rattlesnake scent. Thus, ground squirrels can reduce the risk of rattlesnake predation by applying rattlesnake scent to their bodies, potentially as a form of olfactory camouflage. Opportunistic exploitation of heterospecific scents may be widespread; many species self-apply foreign odours, but few such cases have been demonstrated to serve in antipredator defence.     

四川洪雅县赤腹松鼠的食性观察

2008年1月至2010年8月,在主要树种为柳杉Cryptomeria fortunei的四川省洪雅县林场中,采用直接观察和胃容物分析法对赤腹松鼠Callosciurus erythraeus食性进行研究.发现赤腹松鼠取食的植物共有14科23种,如小柱悬钩子Rubus columellaris和板栗Castanea mollissima的果实,油茶Camellia oleifera的花及柳杉和杉木Cunninghamia lanceolata的树皮.结合往年文献,已知确认洪雅县赤腹松鼠取食的植物共28种.根据胃容物分析,果实种子的比例为秋季(75.60％±0.53％)＞夏季(63.32％±0.69％)＞冬季(34.02％±0.43％)＞春季(14.35％±0.71％),差异显著(P＜0.05);而树皮在夏季和秋季分别为7.32％±0.50％和8.30％±0.87％,显著低于冬季和春季的28.13％±0.72％和28.71％ ±0.84％ (P ＜0.05).根据结果分析,赤腹松鼠的主要食物是植物的果实种子,在冬春取食较多的树皮可能与果实种子短缺有关.     

洪雅县人工林赤腹松鼠活动范围及栖息地利用

2009年3～8月期间,通过观察并利用无线电遥测等方法对洪雅县林场赤腹松鼠(Callosciurus erythraeus)的活动范围和栖息地利用进行了研究。研究结果显示,赤腹松鼠的最小凸多边形(minimum convex polygon,MCP)巢域面积为(1.90±0.59)hm2,95%和60%固定核法(fixed kernel,FK)巢域面积分别为(1.06±0.19)hm2和(0.16±0.03)hm2。处在求偶高峰期的雄鼠会显著地扩大活动范围。栖息地利用的研究结果表明,赤腹松鼠对栖息地因子有明显的选择性,倾向在坡度大、灌木生长繁茂、靠近人居和水源及有藤本植物覆盖的区域活动。     

Ectoparasites of gray squirrels in two different habitats and screening of selected ectoparasites for bartonellae

Gray squirrels, Sciurus carolinensis, were livetrapped in 2 different habitat types, woodland (67 squirrels) and parkland (53 squirrels), in southeastern Georgia. Ectoparasites were recovered from anesthetized squirrels and compared between hosts from the 2 habitats. Because of the absence of low vegetation in parkland habitats, it was hypothesized that the ectoparasite fauna, especially ticks and chiggers, would be more diverse on woodland squirrels. The results were generally in agreement with this hypothesis. Seventeen species of ectoparasites were recovered from woodland squirrels, compared with 6 species from parkland squirrels. Five species of ticks and 3 species of chiggers parasitized the woodland squirrels compared with no ticks or chiggers on the parkland squirrels. Significantly higher infestation prevalences were recorded on woodland compared with parkland squirrels for the flea Orchopeas howardi, the tick Amblyomma americanum, and the mesostigmatid mite Androlaelaps fahrenholzi. The mean intensity for O. howardi also was significantly higher on woodland than on parkland squirrels. Because a new strain of Bartonella sp. was isolated recently from S. carolinensis in Georgia, selected ectoparasites from this study were screened for bartonellae by polymerase chain reaction (PCR). Some of the fleas and lice, but none of the mites tested, were PCR positive, suggesting that fleas, or lice, or both, might be vectors of bartonellae between squirrels. Six distinct strains of Bartonella sp. were detected, 2 in fleas and 4 in lice.     

繁殖期不同时段赤腹松鼠巢域的变化

繁殖期巢域的研究对了解繁殖期间动物的社群关系、种群动态、繁殖策略等有重要作用。2009 年3 ～12月和2010 年3 ～9 月对洪雅县赤腹松鼠的巢域面积变化进行观察。使用最小凸多边形(Minimum convex polygon,MCP)法计算赤腹松鼠各时期的巢域面积,结果显示: (1)整个繁殖期,雄性赤腹松鼠的巢域面积为1.34 ±0. 34 hm² ,显著大于雌性的巢域面积(0.60 ± 0. 08 hm² ); (2)雄性赤腹松鼠在求偶交配期主动增加其巢域面积,可能会增加雄性与雌性的遇见率,从而增加与雌性的交配数量;雌性赤腹松鼠在求偶交配期不主动增加巢域面积,而是具有较为稳定的活动范围。在妊娠育幼期雌性的巢域面积会减小,这可能是雌性为提高后代的成活率,在增加能量和降低捕食风险两者间做出的权衡;(3)整个繁殖期,雌性赤腹松鼠间无巢域重叠现象,而雄性间存在巢域重叠。两性之间仅在求偶交配期存在巢域重叠现象,因此,雌性赤腹松鼠在繁殖期有较强的领域性。     

Genetic mobility of plasmids of Streptomyces erythraeus

Grossing of S. erythraeus 4 with S. erythraeus 1 resulted in transfer of genetic elements from strain 4 to strain 1 as evidence by the 20 and 18 kb fragments in the experiments on DNA-DNA hybridization. The presence of the genetic elements in strain 1 was the cause of plasmid pSE 21 mobility. In strain 6, a derivative of S. erythraeus 1 plasmid pSE 21 was accompanied by other extrachromosomal DNAs characterized by high instability. During storage of the strain at a temperature of 4 degrees C for more than 1 or 2 months the number of the plasmid pSE 21 copies decreased. When the strain was stored for longer periods (6 months or more) the plasmid DNA was not detectable even with the DNA-DNA hybridization procedure. The results of hybridization of a fraction of the extrachromosomal DNA of S. erythraeus 6, the Bam HIB fragment of plasmid pSE 21 with the total DNA of strains 1, 4, 5, 6 and BTCC 2 of S. erythraeus and hybridization of DNA of plasmid pSE 21 with the total DNA of S. erythraeus 6 and 1 showed that (1) strains 1, 5 and BTCC 2 had the same hybridization patterns, (2) the other extrachromosomal DNAs present in the fraction were homologous with the Bam HIA fragment of plasmid pSE 21, (3) chromosomes of strains 1, 4, 5, 6 and BTCC 2 of S. erythraeus also contained DNA homologous to the plasmid Bam HIA fragment. It was suggested that plasmid pSE 21 could be used as a basis for constructing the integrative vector for S. erythraeus.     

Restriction mapping and close relationship of the DNA of Streptomyces erythraeus phages 121 and SE-5

The biological properties and genome structure of two actinophages, 121 and SE-5, infecting Streptomyces erythraeus were characterized. They had the same host range (limited to S. erythraeus) and similar DNA G + C contents (around 60 mol %). Restriction maps of their genomes also showed many similarities. The close relationship between the two phages was confirmed by DNA hybridization experiments: large parts of their genomes were homologous, except for a segment in the middle of the map, where no hybridization was detected.     

Spacing and kinship in the Formosan squirrel living in different habitats

Summary Spacing and kinship of the Formosan squirrel, Callosciurus erythraeus thaiwanensis, were studied in two different habitats. One, native habitat in the woods of Kenting, southern Formosa, was rich in available food throughout the year and had several species of predators. The other, a site in Kamakura, central Japan where squirrels had been introduced, had relatively scanty food and few potential predators. 1. Home ranges among males and between sexes overlapped extensively in both habitats. 2. Females occupied exclusive home ranges in Kamakura but had small overlapping home ranges in Ken-ting. 3. Most males disappeared from their natal areas at 1 year old in both habitats (86% in Kamakura and 93% in Ken-ting), but less females disappeared (36% in Kamakura and 35% in Ken-ting). 4. In Kamakura, daughters settled adjacent to the mother or inherited the home range of the mother, but never shared the mother's home range. In Ken-ting, 35% of daughters shared the home range with their mothers. 5. Tolerance among female kin in Ken-ting was probably facilitated by the richness of available food throughout the year, and functioned to reduce predation risk via alarm calling and mobbing.     

The Mechanism of Replacement of Red Squirrels by Grey Squirrels: A Test of the Interference Competition Hypothesis

Introduced American grey squirrels have replaced native red squirrels in most of the range currently occupied in Britain and northern Italy. The mechanisms of the replacement are not yet fully understood. We restated the commonly cited Interference Competition Hypothesis (ICH) that grey squirrels interfere with the behaviour of red squirrels in three possible ways: 1. by direct aggressive interactions; 2. by interrupting red squirrel mating-chases; or 3. by forcing red squirrels to actively avoid areas intensively used by grey squirrels. We compared the activity pattern, behaviour and reproductive performance of red squirrels in two study areas in northern Italy, one with only red squirrels (control area C1), the other with both species (experimental area E1). The following predictions were tested: 1. the total time spent in both intraspecific and interspecific interactions by red squirrels increases in the experimental area; 2. most interspecific interactions are aggressive, with grey squirrels being the dominant species; 3. the proportion of breeding female red squirrels that are unsuccessful at weaning offspring increases in area E1; 4. grey squirrels take part and interfere with red squirrel mating-chases, and thereby decrease the reproductive output of red squirrel females; 5. the activity pattern of red squirrels in the mixed-species area is shifted with respect to that in the control area to the hours of the day during which grey squirrels show little activity; and 6. red squirrels will shift their home range (or at least their core-area) when grey squirrel densities increase to avoid interspecific core-area overlap. Our results supported only the first prediction of the ICH: they failed to support all the other predictions. Moreover, the increase in the percentage of active time red squirrels spent interacting with other squirrels in the experimental study area was very small (only 1–2 min/day). Red squirrels did not avoid the woodland patches most intensively used by grey squirrels and the interspecific core-area overlap was similar to red squirrel intraspecific core-area overlap. This suggested that red squirrels avoided spatial overlap with grey squirrels in a similar manner as with conspecifics and that an increase in grey squirrel numbers will augment the intensity of resource competition. We therefore conclude that our results do not lend support to the Interference Competition Hypothesis and that interference competition by grey squirrels cannot explain the large-scale replacement of red by grey squirrels that has occurred in Britain and in Piedmont.     

Taxonomy of the Carex flava complex (Cyperaceae) in Finland

The morphological variation in the Carex flava complex (sect. Ceratocystis ) in Finland, particularly taxa described by Alvar Palmgren as endemic to northern Europe, was studied using numerical analyses. Discriminant analyses were used to maximize the separation of the taxa. However, the separation of the taxa described by Palmgren was weak. The taxonomic treatment of the C. flava complex in Finland based on morphology, ecology, distribution and hybridization of the taxa is presented. Four species are recognized: Carex flava (the lectotype is selected here), C. lepidocarpa, C. demissa and C. viridula. C. lepidocarpa includes ssp. lepidocarpa and ssp. jemtlandica . In the polymorphic C. viridula , three taxa are recognized: var. viridula , var. bergrothii and var. pulchella . A key to the taxa is presented. The distribution of the taxa in Finland is presented, and their ecology is briefly discussed.     

利用红外相机技术对九连山国家级自然保护区兽类和鸟类资源的初步调查

九连山国家级自然保护区是我国中亚热带与南亚热带常绿阔叶林的过渡地带,动植物种类丰富多样。为进一步掌握该保护区野生动物资源现状,我们于2014年11月至2015年7月在保护区布设了31个红外相机监测点,对大中型兽类和林下活动鸟类进行了初步摸底调查。相机累计工作4 692个捕获日,共获得有动物的独立有效照片3 341张,鉴定出鸟兽物种共10目16科33种（兽类12种,鸟类21种）。属于国家Ⅱ级重点保护动物有斑灵狸（Prionodon pardicolor）、白鹇（Lophura nycthemera）和灰脸鵟鹰（Butastur indicus）等。兽类以赤腹松鼠（Callosciurus erythraeus）、白腹鼠种类（Niviventer rats）、小泡巨鼠（Leopoldamys edwardsi）和倭松鼠（Tamiops maritimus）等物种的相对丰富度指数较高。相对丰富度指数较高的鸟类物种依次为白鹇、紫啸鸫（Myophonus caeruleus）和黑领噪鹛（Garrulax pectoralis）等。结合以往记录,灰头绿啄木鸟（Picus canus）、乌灰鸫（Turdus cardis）、绿翅金鸠（Chalcophaps indica）、白眉鸫（Turdus obscurus）和白冠燕尾（Enicurus leschenaulti）等为保护区的鸟类新记录种。本研究的调查结果为进一步在九连山自然保护区开展鸟兽资源的长期监测奠定了基础。     

赤腹松鼠一新亚种

在查对中国南部赤腹松鼠标本(401号)的基础上,发现分布于云南东北部昭通地区的赤腹松鼠与赤腹松鼠其他亚种有明显的区别.毛色特征:背部棕黄色,背中央区域稍带黑色;腹部至前胸栗红色;喉、颏部棕灰色;尾毛背腹无明显差异,尾毛末端棕黄、次末端黑,尾末端具棕黄色(稍黄白)区域;前后足背棕褐色,稍带黑色.进一步对头骨可量性状数据进行分析(差异系数),结果表明:分布于该地区的赤腹松鼠分别与赤腹松鼠其他13个亚种两两之间至少有一项差异系数大于1.28,系一新亚种Callosciurus erythraeus zhaotongensis subsp.nov..     

Ixodid tick species recovered from domestic dogs in Japan

The species of ixodid ticks (Acari: Ixodidae) recovered from domestic dogs in Japan between September to November 2000 and April to June 2001 were identified. A total of 4122 ticks, including 1624 larvae, 1200 nymphs, 1016 females and 282 males were removed from 1221 dogs during these periods. Haemaphysalis longicornis (Neumann) was the most frequently found (40.3% of dogs), followed by H. flava (Neumann) (16.1% of dogs), Rhipicephalus sanguineus (Latreille) (4.8% of dogs) and Ixodes ovatus (Neumann) (4.1% of dogs). Small numbers of H. hystricis (Supino), H. campanulata (Warburton), H. japonica (Warburton), H. ias (Nakamura and Yajima), I. persulcatus (Schulze), I. nipponensis (Kitaoka and Saito) and Amblyomma testudinarium (Koch) were also recovered. In the spring sample, a total of 1408 ticks (78 larvae, 411 nymphs, 792 adult females and 127 adult males) were recovered from 570 dogs. The autumn sample included a larger proportion of larval stage and fewer adult ticks (1546 larvae, 789 nymphs, 224 adult females and 155 adult males). Haemaphysalis longicornis, H. flava and I. ovatus showed a wide geographical distribution from northern to southern Japan, whereas R. sanguineus were mainly distributed in the subtropical Okinawa prefecture with a few exceptions. Dogs in rural areas more frequently carried H. longicornis, H. flava and I. ovatus than dogs in urban or suburban areas, whereas R. sanguineus was more associated with the dogs in urban/suburban areas. Exposure to a garden was significantly associated with R. sanguineus and exposure to woodland was significantly associated with H. flava and I. ovatus. This is the first systematic survey of canine ticks in Japan.     

Identification of potential hosts and vectors of scrub typhus and tick-borne spotted fever group rickettsiae in eastern Taiwan

Scrub typhus and tick-borne spotted fever group (SFG) rickettsioses are transmitted by chiggers (larval trombiculid mites) and hard ticks, respectively. We assessed exposure to these disease vectors by extensively sampling both chiggers and ticks and their small mammal hosts in eastern Taiwan during 2007 and 2008. The striped field mouse Apodemus agrarius Pallas (Rodentia: Muridae) was the most common of the small mammals (36.1% of 1393 captures) and presented the highest rate of infestation with both chiggers (47.8% of 110 760) and ticks (78.1% of 1431). Leptotrombidium imphalum Vercammen-Grandjean & Langston (Trombidiformes: Trombiculidae) and immature Rhipicephalus haemaphysaloides Supino (Ixodida: Ixodidae) were the most abundant chiggers (84.5%) and ticks (>99%) identified, respectively. Immunofluorescent antibody assay revealed high seropositive rates of rodents against Orientia tsutsugamushi Hyashi (Rickettsiales: Rickettsiaceae), the aetiological agent of scrub typhus (70.0% of 437 rodents), and tick-borne SFG rickettsiae (91.9% of 418 rodents). The current study represents a first step towards elucidating the potential hosts and vectors in the enzootic transmission of O. tsutsugamushi and tick-borne SFG rickettsiae in Taiwan. Further studies should focus on characterizing pathogens in L. imphalum and R. haemaphysaloides, as well as the proclivity of both vectors to humans. Uncovering the main hosts of adult ticks is also critical for the prevention of SFG rickettsial infections.     

赤腹松鼠血清肝肾功能指标的测定

以捕自四川荥经县的161只成体赤腹松鼠(Callosciurus erythraeus,雄鼠76只,雌鼠85只)为研究对象,从2015年2月至12月分四个季节测定了雌、雄鼠血清中反映肝肾功能的14项指标,并分析了妊娠对各项指标的影响。结果显示:(1)肝肾功能指标均无显著的性别差异。(2)白蛋白、胆碱酯酶和肌酐在春季有升高的趋势,但无明显的季节差异。(3)总蛋白、球蛋白及尿酸含量春季低于其他季节,总胆红素、直接胆红素、间接胆红素和尿素氮含量春季高于其他季节,前白蛋白、丙氨酸氨基转移酶、天冬氨酸氨基转移酶和γ-谷氨酰转移酶春季高于其他季节,夏季显著下降,冬季最低。(4)妊娠鼠血清胆碱酯酶含量高于未妊娠鼠,尿素氮、肌酐和尿酸含量低于未妊娠鼠。结果表明,雌、雄赤腹松鼠肝肾功能指标无性别差异且季节变化趋势相同,大多数在春季变化显著且妊娠影响较小,这可能与雌、雄的繁殖状态及在多变性环境条件下的生理适应能力有关。