New data on nuclear transplantation in mammals

The results of studies on nuclear transplantation in mammals published in 1986 allow to suppose the causes of failure in experiments on mice and outline ways of overcoming these difficulties.     

Helminth communities in small mammals in southeastern New South Wales

• 1.1. Changes in the composition and abundance of 5 marsupial and 3 eutherian mammal species, and of their helminth communities pre- and post-perturbation by wildfire at Nadgee and Timbillica State Forests in southeastern coastal New South Wales during the period September 1977 to September 1985 are reported.
• 2.2.Dasyurid marsupials (Antechinus stuartii, Antechinus swainsonii and Sminthopsis leucopus), peramelid marsupials (Perameles nasuta and Isoodon obesulus) and native eutherian rodents (Rattus fuscipes and Rattus lutreolus) occurred pre-fire. These species and the introduced house mouse (Mus musculus) occurred post-fire.
• 3.3. All host taxa harboured a diverse helminth fauna dominated by nematodes. The helminth communities in A. stuartii, A. swainsonii, S. leucopus and R. lutreolus represented more than 70%, those in P. nasuta, R. fuscipes and M. musculus represented more than 50% and that in I. obesulus represented less than 40% of the total helminth faunas known to occur in these hosts throughout their geographic ranges in Australia.
• 4.4. Adult nematodes of Capillaria sp. 11 and Tetrabothriostrongylus mackerrasae occurred in all host groups, those of Peramelistrongylus skedastos occurred in both marsupial groups but not in rodents, larval stages of the ascaridoid nematode Ophidascaris robertsi occurred in all host groups and physalopterid nematode larvae believed to be Abbreviata spp. occurred in dasyurid marsupials and in rodents but not in peramelid marsupials.
• 5.5. Four helminth communities were recognised: one in the dasyurid marsupials, a second in the peramelid marsupials, a third in the native rodents and a fourth in the introduced house mouse.
• 6.6. Differences in the helminth communities in host taxa pre- and post-wildfire were associated with the ecological strategies of the hosts and their roles as opportunistic invaders (M. musculus), fire-enhanced species (S. leucopus) or slow recolonisers (P. nasuta) post-perturbation by wildfire.

     

试论动物考古中的小哺乳动物研究

小哺乳动物种类及其数量,在哺乳动物中占据大多数。它们是自然界生态链中非常重要的、不可缺少的环节。它们体质进化较快,大部分种类居住区域选择性强,种群活动范围比较小。所以研究小哺乳动物种群面貌及其生态特征,可以帮助我们判断古遗址相对时代,解析历史时期的生态演变。小哺乳动物的生态指示性,能够帮助我们准确复原和研究古遗址环境背景。它们的分布状况及很多生态规律,在帮助我们研究古遗址环境卫生及古居民住房条件等方面有独特作用。小哺乳动物种群变化与人类经济生产的互动性,以及它们与人类的伴栖关系、人类对小哺乳动物资源的开发和利用等,均是动物考古工作中应该重视和积极开展研究的内容。开展小哺乳动物研究,需要必要的工作计划、专业技术和实验设备。我国旧石器时代的小哺乳动物考古已取得丰硕成果,新石器时代及其以后的小哺乳动物考古尚有待加强。小哺乳动物研究工作的拓展,将会有力促进动物考古学进展,促使动物考古在考古学实践中发挥出更大作用。     

New data on late Miocene mammals of Kohfidisch, Austria

Cervids and bovids of the Early Turolian mammalian fauna of Kohfidisch (Austria) are reviewed. A new species, Micromeryx mirus sp. nov. (Moschidae) is described.     

New data on birds and mammals population of the Sette-Daban Mountain Ridge

Original materials on the fauna of the northern macroslope of the Sette-Daban Mountain Ridge are presented. Birds and mammals population in different habitats in the basin of the Allakh-Yun River are characterized.     

Cryptosporidium spp. from small mammals in the New York City watershed

The objective of this study was to assess the potential role that wildlife plays in environmental degradation of watersheds through the contamination of the water supply with zoonotic genotypes of Cryptosporidium. Cryptosporidium isolates recovered from wildlife in the New York City (NYC) watershed were examined to determine genotype using a polymerase chain reaction protocol targeting the 18-Small Subunit (SSU) rRNA locus. Seventy-seven DNA samples recovered from 12 wildlife host species captured in the NYC watershed were amplified and sequenced. Data on risk factors associated with the perpetuation of these genotypes also were collected and analyzed. Although many genotypes appeared to be host-specific, 38% of the samples examined were identified as Cryptosporidium parvum, indicating the presence of zoonotic Cryptosporidium. Adult animals were more likely to shed the zoonotic strains of Cryptosporidium spp. Animals captured in the fall and winter were more likely to be infected with C. parvum than those captured in spring and summer.     

Simulated removal trapping considered in connection with actual census data in small mammals

A record of simulated removal trapping of 50 samples drawn from N=50 under a design has been considered as to how it does contribute to practical censuses of small mammals. It follows that, for ordinary-density populations so far experienced, the removal census based on the theory may frequently lead to quite wrong estimates from single-plot data by the simplest method, and that the maximum likelihood method is doubtless better, but even this method may produce right estimates in about half of the cases, their standard error being of limited availability. Therefore pooling of data from many plots are desirous for such populations.     

New regression formula to estimate the whole population for recapture-addicted small mammals

We have devised a census formula of curvilinear regression suitable for capture-recapture data of recapture-addicted populations of the Japanese field vole (Microtus montebelli) obtained under a grid-plan with single-catch traps in order to estimate the whole population. The equation is founded on the assumption that the trappable population on the initial day is increased in way of an exponential curve until it reaches to the whole during one trapping period. The effect of trap-preoccupation by marked and multiple collisions is considered in the formula. As a result of its application to field data of the vole, it has turned out that the equation is required for the data gained under the trapping plan with trap spacing 10m, but not for those under the plan with spacing 5m, to estimate the whole. A convenient method of analysis of the formula is offered here, but we have been yet unable to introduce assymptotic variance of estimates.     

Trypanosomes of small mammals in Iran

Trypanosomes in the subgenera Herpetosoma, Schizotrypanom and Megatrypanum were found in 31 small mammals representing nine species of the orders Rodentia, Insectivora and Chiroptera in Iran.     

Polyphasic activity patterns in small mammals

Cathemeral species are routinely active during the day, the night and at twilight. For the majority of species it is advantageous to specialize on the environmental conditions of a particular phase of the 24-hour day, so this rather uncommon type of activity must be a consequence of specific constraints. Good examples are the polyphasic activity patterns found in some small mammals. In shrews, with small body size and extremely high metabolic rate, polyphasic activity represents a simple short-term hunger cycle. In voles the short-term rhythm is triggered by an additional endogenous ultradian clock that interacts with the common circadian system, which probably is functionally related to endosymbiont digestion of cellulose-rich food. The activity bouts of individuals are synchronized on the population level to spread predation risk. As cathemeral species, voles are not specifically adapted to particular light conditions, but they are also not restricted to a particular activity phase. Therefore, the benefits from flexible responses in activity timing to environmental challenges may compensate for the disadvantages of not being specialized.     

Isotopic partitioning by small mammals in the subnivium

In the Arctic, food limitation is one of the driving factors behind small mammal population fluctuations. Active throughout the year, voles and lemmings (arvicoline rodents) are central prey in arctic food webs. Snow cover, however, makes the estimation of their winter diet challenging. We analyzed the isotopic composition of ever‐growing incisors from species of voles and lemmings in northern Finland trapped in the spring and autumn. We found that resources appear to be reasonably partitioned and largely congruent with phylogeny. Our results reveal that winter resource use can be inferred from the tooth isotopic composition of rodents sampled in the spring, when trapping can be conducted, and that resources appear to be partitioned via competition under the snow.