Species composition, host association and niche differentiation in fleas of small mammals in the Ilmen-Volkhov lowland

Species composition, abundance, annual cycles, and host association of fleas parasitizing small mammals were investigated. The problem of niche differentiation in these insects is considered on the base of the comparative analysis of their annual cycles. The annual cycles of the fleas are revealed to be similar in the case of few number of flea species in parasite community. Thus, two species parasitizing Sorex araneus (Doratopsylla dasycnema and Palaeopsylla soricis), as well as three species associated with Apodemus uralensis (Megabothris turbidus, Ctenophthalmus agyrtes, and Ct. uncinatus) have equal phenology of parasitizing. The fleas community of Clethrionomys glareolus is characterized by a large species number and high diversity of the annual cycles. The differentiation by the seasons of parasitizing is observed most clearly in the dominant flea species, namely Amalaraeus penicilliger, Ct. uncinatus, and Peromyscopsylla bidentata. The periods of imaginal life are overlapped significanly in these species, but they are differed by the season of dominance. Ct. uncinatus predominates in spring and summer, while P. bidentata predominates in autumn, and A. penicilliger predominates in winter and early spring. It may be noted also, that niche partitioning was not observed in the fleas having wide range of hosts. The imaginal life of such fleas usually does not go beyond the warm season.     

The seasonal dynamics of fleas (Siphonaptera) on bank voles (Clethrionomys glareolus) in the north part of Novgorod region

The twelve flea species were revealed on bank voles. Only four of them (Amalaraeus penicillige, Ctenophthalmus uncinatus, Megabothris turbidus, Peromescopsylla bidentata) were abundant in some seasons of the year. Four other species (Ct. agyrtes, Hystrichopsylla talpae, P. silvatica, Rhadinopsylla integella) are the parasites of bank vole too but their numbers were always low in the study area. The four last species (Amphypsylla rossica, M. walkeri, Doratopsylla dasycnema, Palaeopsylla soricis) are not peculiar to bank vole. They occurs on it occasionally from other animals--the voules of Mucrotus and shrews. The most species diversity of fleas on bank vole was observed at the period from August to October, the least one--in late winter, spring and early summer. The total abundance indices of fleas on the voles (mean number of the insects per host) ranged in different months from 0.17 to 5.65. The time of minimum flea numbers was August-September. The peak abundance was reached in springtime (March-April).     

Studies on the biology of the Pygmy shrew Sorex minutus in the West of Ireland

Pygmy shrews were snap-trapped over one year in grassland and occasionally in other habitats. The bodies yielded data on tooth-wear, body and skull dimensions, moulting, reproduction, food and parasites. The shrews appeared equally abundant in grassland and woodland and were more active in the day. The breeding season, population turnover, and winter body and skull regression were similar to those of other Sorex species. However, cranial regression was more marked: this may be associated with the animal's exceptionally small size. Moulting extended in autumn from August to November, and in spring from March to May, the latter in males starting earlier and perhaps lasting longer. Simultaneous and patch moults were also recorded. The litter size dropped as the breeding season progressed. The main foods were beetles, woodlice, Diptera and insect larvae; all except Diptera were eaten consistently over the year. There was a wide variety of other foods, many showing seasonal fluctuations. The commonest flea was Doratopsylla dasycnema. Palaeopsylla soricis, a common shrew-flea, widespread in the British Isles, is at least locally absent. Pygmy shrews may be the principal host of Hystrichopsylla talpae in Ireland. Rates of infestation by the trematodes and one cestode appeared to increase as the hosts aged. The tapeworm Hymenolepis scutigera, however, was commonest in juveniles. It is postulated that Doratopsylla dasycnema is its intermediate host, allowing infection of young before they leave the nest. Sorex araneus is sympatric with Sorex minutus over most of its range, but not in Ireland. In its absence, S. minutus may have been able to exploit its niche, the apparent abundance of the latter in woodland and wider variety of food consumed providing grounds for such a hypothesis.     

Structure and seasonal dynamics of an ectoparasite community on the common shrew (Sorex araneus) in the Il'men'-Volkhov lowland

Species composition, seasonal dynamics, and a load of ectoparasites per individual and population of the common shrew Sorex araneus have been examined in coniferous and mixed forests of the Ilmen'-Volkhov lowland (a neighbourhood of Oskuy village, Chudovo district, Novgorod Province) during the period 1999-2003. Trapping of mammals was carried monthly, with exception of few accidental gaps. The Gero traps were used for catching micromammalian hosts. The lines of trap were checked 2 times a day, places of lines changed each 3-5 day. Total number of micromammalians collected during the period of study is 3215, including 1115 specimens of the common shrew S. araneus and 246 ones of the pigmy shrew S. minutus. Parasite fauna on the common shrew included 23 ectoparasite species: fleas--12, ixodid ticks--2, gamasid mites--7, and myobiid mites--2 species. Among recorded species, 9 fleas species and some gamasid species are accidental parasites. These accidental ectoparasite species are common to the bank vole Clethrionomys glareolus in the territory investigated. Species composition, occurrence and abundance indices of parasites changed during the year. In total, about 55% shrew specimens are infected with ectoparasites. The infracommunity of ectoparasites on the common shrew usually consists of 6 species or less. Mean number of all ectoparasite individuals per one host specimens varies from 4 to 83. The greatest number of parasites (50 and 83) was recorded on the shrews, which carried 5 and 4 parasites species, respectively. Biodiversity of parasite species in the ectoparasite community on the common shrew and the load of parasites per one host specimen are lower than those in the bank vole. In forest biotopes explored, the most part of temporary ectoparasite species found on the common shrew was also recorded on other small mammals, which could have contacts with this host. It is possible to conclude that among the parasite supracommunity in the explored ecosystem, the temporary ectoparasites represent a "fond" of temporary parasites, which are common for most small mammal species. A role of different shrew and rodent species as main of additional hosts changes depending on a population density of potential mammalian hosts and other environment factors.     

Structure of populations and ecological nishes of ectoparasites in the parasite communities of small forest mammals

The paper reports the results of eight-year investigations on the ectoparasites of rodents and insectivores carried out in southern taiga of the Ilmen-Volkhov lowland (Novgorod Region) and Kurgolovsky reserve (Leningrad Region). Twelve species of small mammals were captured including three dominate species--bank vole Clethrionomys glareolus (2722 specimens), common shrew Sorex araneus (1658 specimens), and wood mouse Apodemus uralensis (367 specimens). Parasite community of the bank vole comprises 34 species of mites, ticks, and insects, the community of common shrew comprises 25 species, and the community of A. uralensis includes 28 species. Taxonomic diversity of the ectoparasite communities was shown to be based on the diversity of types of parasitism and ecological nishes of the host body. Permanent ectoparasites are found to be represented by 2 species of lie and 14 species of acariform mites. The group of temporary parasites includes 13 species of fleas, 10 species of gamasid mites. 3 ixodid species and 1 Trombiculidae. There is a common pool of temporary parasites of small mammals in the ecological system of taiga. Significance of different shrew and rodent species as hosts were found to be dependent on the population density in possible hosts and many other factors. Species diversity in the parasite communities of different small mammal species is dependent on the number of possible ecological nishes in the host body. Actual infill of these nishes by ectoparasites is usually lesser than potential one. Species composition of temporary parasites, their occurrence and abundance changes according to season. Interspecific competition in the temporary parasite species can decrease because of the seasonal disjunction of their population peaks. Diversification of the ecological niches of ectoparasites allow simultaneous feeding of more parasite individuals on one host, than in the case of parasitising of single species or several species with similar ecological nishes. The distribution of parasites on their hosts was also studied. The aggregative distribution has been found in ixodid larvae only, and the distribution of fleas was close to the Poisson distribution. Deviations from the aggregative distribution can be an effect of several independent factors, including limited ability of small mammals for providing numerous parasites with food. On the most part of hosts simultaneous parasitizing of no more than 1-3 individuals of each tick, mite, and flea species was registered. Excessive infestation by ectoparasites may probably be limited by effective reactions of self-purification in the mammal hosts.     

Zum auftreten von Kleinsäuger-Flöhen auf ihren wirten in Abhängigkeit von Jahreszeit und Höhenstufen

Zusammenfassung Die jahreszeitlich und höhenabhängigen Veränderungen des Flohbefalls alpiner Kleinsäuger werden dargestellt. Die Daten basieren auf einer in 3 Untersuchungsgebieten Tirols zwischen 1966 und 1969 durchgeführten Untersuchung in verschiedenen Höhenstufen der Alpen (625 Muridae und Soricidae, 1136 Siphonaptera). Durch den Vergleich der Aufsammlungen aus Tallagen und aus der subalpinen-alpinen Stufe sowie aus den verschiedenen Jahreszeiten können für einige Arten (z. B. Doratopsylla dasycnema, Palaeopsylla soricis, Ctenophthalmus orphilus, Amphipsylla sibirica sepifera, Peromyscopsylla bidentata und P. fallax) nähere Einzelheiten über deren Abundanzmaxima gegeben werden. Die Kleinsäuger der subalpinen-alpinen Stufe erwiesen sich als weniger befallen als die der Talregion, in der warmen Jahreszeit war die Flohausbeute reichhaltiger als während der Wintermonate. Die Befallsextensität und-intensität war bei Soriciden erheblich größer als bei den Muriden.

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The flea infestation of small alpine mammals and its dependence on the time of the year and altitude

Summary The infestation of small alpine mammals with fleas during the year and at different altitudes was investigated. The data are based on an investigation carried out between 1966 and 1969 in Tirol (Austria) in different altitudinal zones of the alps, 1136 fleas having been collected from 625 insectivores and rodents. By comparing the collections from the lower and higher regions and from different seasons of the year details of the pattern of distribution can be given for some species of fleas (e.g. for Doratopsylla dasycnema, Palaeopsylla soricis, Ctenophthalmus orphilus, Amphipsylla sibirica sepifera, Peromyscopsylla bidentata, P. fallax). The hosts in the subalpine and alpine zone proved to be less infested by fleas than the mammals of the lower regions, during the warm season the hosts harboured more parasites than during winter. Extensiveness and intensity of infestation were constantly higher in Soricidae than in Muridae.

     

The seasonal dynamic of fleas (Siphonaptera) abundance on apodemus uralensis in the northen part of Novgorod Region

Seven fleas species were revealed on Apodemus uralensis. Only three of them (Ctenophthalmus agyrtes, Ct. uncinatus, Megabothris turbidus) are the main parasites of this rodent species and have similar phenology of imago. They appear in April, parasitise during spring and summer periods and disappear in autumn, in September-October. The abundance of all three species shows two peaks in a year, which correspond to two generations. Four species (Amalaraeus penicilliger, Ct. bisoctodentatus, Peromyscopsylla bidentata, P. silvatica) are not peculiar to Apodemus uralensis. They pass on this host species occasionally from other animals inhabiting forest biotopes.     

Host range and distribution of small mammal fleas in South Africa,with a focus on species of medical and veterinary importance

The host range and distribution of flea species on rodents and insectivores across multiple vegetation types in South Africa were investigated. Habitat suitability for flea species considered as important vectors of disease in humans and domestic animals was modelled. Data originated from fleas that were recovered from small mammals captured at 29 localities during 2009–2013 and published literature searched for flea records. Climate‐based predictor variables, widely used in arthropod vector distribution, were selected and habitat suitability modelled for 10 flea vector species. A total of 2469 flea individuals representing 33 species and subspecies were collected from 1185 small mammals. Ten of each of the flea and rodent species are plague vectors and reservoirs, respectively. Multiple novel flea–host associations and locality records were noted. Three vector species were recorded from insectivores. Geographic distributions of flea species ranged from broad, across‐biome distributions to narrower distributions within one or two biomes. Habitat suitability models performed excellently for the majority of flea vectors and identified regions of summer and all‐year rainfall as representing suitable habitats for most vector species. Current knowledge of vector and disease ecology can benefit from similar sampling approaches that will be important not only for South Africa, but also for the sub‐region.     

Parasite-host relationship of flies and small mammals in the Omsk region

A generalized analysis of data on a flea fauna, range of their hosts in various natural zones, and features of parasite-host relationships between fleas and small mammals obtained in the Omsk province during long term researches in 1963-1997 is given. 35 flea species are recorded. The most mass species both on animals and in their nest is Ctenophthalmus assimilis; the numerous species are Amalareus penicilliger, Megabothros rectangulatus, M. walkeri, Peromyscopsylla silvatica, Ctenophthalmus unciatus, Palaropsylla sorecis, Doratopsilla birulai, Neopsylla pleskei, Hystrichopsylla talpae; the usual species--Ceratopsyllus garei, M. calcarifer, M. turbidus, Frontopsylla elata, Amphipsylla sibirica, A. kuznetzowi, Peromyscopsylla dasycnema, Radinopsylla integella, Catalagia dacenkoi. Other species are less numerous or infrequent. The general infection rate of the flea populations on rodents and insectivores makes 30.4%. For certain species it reaches 65.1% (on red-backed vole Cletrionomys rutilus), for regular groups--86.9% (on shrews of the genus Sorex). The greatest variety of the flea populations is observed on Microtus arvalis, the least one--on Sorex caecutiens and S. daphaenodon. In the nests of small mammals the variety of fleas is significantly lower. Based on the index of flea species relative "loyalty" to small mammals and their nest we have recognized 6 groups of fleas.     

Flea species infesting dogs in Spain: updated spatial and seasonal distribution patterns

This entomological survey examines the spatial and seasonal distribution patterns of flea species infesting dogs in Spain. Bioclimatic zones covering broad climate and vegetation ranges were surveyed according to size. In a cross‐sectional spatial survey carried out from late May 2013 to mid‐July 2015, 1084 dogs from 42 different locations were examined. A total of 3032 fleas were collected and identified as belonging to the following species: Ctenocephalides felis (Siphonaptera: Pulicidae) (81.7%, 2476 fleas); Ctenocephalides canis (11.4%, 347 fleas); Pulex irritans (Siphonaptera: Pulicidae) (6.9%, 208 fleas), and Echidnophaga gallinacea (Siphonaptera: Pulicidae) (0.03%, one flea). Variables observed to have effects on flea abundance were animal weight, sex, length of hair and habitat. In the seasonal survey conducted from June 2014 to June 2015, 1014 fleas were collected from 239 dogs at 30 veterinary practices across Spain. Peaks in C. felis abundance were observed in early summer and late autumn, whereas high numbers of P. irritans and C. canis were recorded in autumn. Numbers of fleas detected in winter were low overall. Based on these findings, the present study updates the spatial and seasonal distributions of flea species in Spain and assesses the impacts of host and habitat variables on flea infestation.     

Abundance patterns of two Oropsylla (Ceratophyllidae: Siphonaptera) species on black-tailed prairie dog (Cynomys ludovicianus) hosts.

Behavioral, genetic, and immune variation within a host population may lead to aggregation of parasites whereby a small proportion of hosts harbor a majority of parasites. In situations where two or more parasite species infect the same host population there is the potential for interaction among parasites that could potentially influence patterns of aggregation through either competition or facilitation. We studied the occurrence and abundance patterns of two congeneric flea species on black-tailed prairie dog (Cynomys ludovicianus) hosts to test for interactions among parasite species. We live-trapped prairie dogs on ten sites in Boulder County, CO and collected their fleas. We found a non-random, positive association between the two flea species, Oropsylla hirsuta and O. tuberculata cynomuris; hosts with high loads of one flea species had high loads of the second species. This result suggests that there is no interspecific competition among fleas on prairie dog hosts. Host weight had a weak negative relationship to flea load and host sex did not influence flea load, though there were slight differences in flea prevalence and abundance between male and female C. ludovicianus. While genetic and behavioral variation among hosts may predispose certain individuals to infection, our results indicate apparent facilitation among flea species that may result from immune suppression or other flea-mediated factors.     

Host associations and origin in the formation of the Caucasian fauna of fleas (Siphonaptera)

Results of analysis of the Caucasian fauna of fleas and their association with mammal and avian hosts are reported. The Caucasian fauna of potential flea hosts comprises about 130 species of mammals and about 470 species of birds. Most of the flea species in the Caucasian fauna (88 out of 155) parasitize rodents, 51 species of which are permanent hosts of different flea species; 13 flea species occur on 11 species of insectivores; 13 flea species, on 13 species of chiropterans; 14 flea species, on 20 species of carnivores. Only 2 flea species parasitize artiodactyles. 54 species of birds are permanent hosts of 23 species of fleas from 4 genera in the Caucasus. Ten types of ranges of flea species are distinguished; host associations of the Caucasian flea species from these groups are discussed. The greatest numbers of hosts from the families Cricetidae, Muridae, and Sciuridae are associated with fleas with Euro-Asian (extra-Siberian), European, Turanian, and Iranian ranges. Soricidae are known as hosts of flea species with European and Euro-Turanian ranges. Four major groups of flea taxa are represented in the Caucasian fauna. The distribution of the first group is determined by the influence of the palaeofauna of the ancient European continent in the early Cenozoic; that of the second group, by the influence of the fauna of the ancient Asian continent during the Paleogene and part of the Neogene; the third, by the influence of the fauna of southern Europe starting with the Miocene. The fourth group comprises the species which immigrated from northern Europe and Asia in the Late Neogene (2–3 mln years ago).     

Quantitative estimation of population numbers of shrews (mammalia,insectivora) after wintering

Autumn-winter mortality in shrews (Sorex araneus, S. caecutiens, S. minutus) was estimated on the basis of long-term (12 years) live-trapping on the permanent transect lines in Tver oblast. Relative as well as absolute population numbers were estimated. Lesser shrew (S. minutus) has permanently low population numbers. Fall in this species made 40.1%, and it was scattered through this term. Common shrew (Sorex araneus) lose 89.3% of population and in masked shrew (S. caecutiens) those lost was 73.6%. The most lost was found in autumn and winter fall was as least as 38,2% and 30.4% in the latter two species. The mortality is positively dependent on population density in preceding summer and with severity of winter.     

An investigation of the population ecology of syntopic shrews inhabiting water-cress beds

The population ecology of the shrews Neomys fodiens, Sorex araneus and S. minutus living syntopically in an area of commercial water-cress beds was investigated by live-trapping over a two-year period. The shrew population comprised 52% 5. araneus , 31% N. fodiens and 17% S. minutus. Sorex araneus was the most numerous species in all seasons. Peak numbers of shrews occurred in summer with low numbers in the ensuing winter. Input of new individuals was high, especially of N. fodiens which exceeded 60% in most months. Survival in the study area never exceeded 8 months in N. fodiens and 11 months in S. araneus. Both species suffered approximately 50% mortality and emigration in the first two months of life. Apart from a few, more nomadic, shrews, N. fodiens and S. araneus seemed quite sedentary during trapping periods, moving a mean distance of 13.7 m and 17.2 m between successive captures, respectively. The relatively low numbers of recaptures of N. fodiens at successive trapping periods indicated nomadic behaviour. Both species were more active during darkness than during daylight, and were more active in spring and summer than in winter. High turnover of the shrew population was attributed to mortality and emigration. Emigration was possibly encouraged by competition for space, particularly for nesting sites.     

Ectoparasitic "jacks-of-all-trades": relationship between abundance and host specificity in fleas (Siphonaptera) parasitic on small mammals

Animal species with larger local populations tend to be widespread across many localities, whereas species with smaller local populations occur in fewer localities. This pattern is well documented for free-living species and can be explained by the resource breadth hypothesis: the attributes that enable a species to exploit a diversity of resources allow it to attain a broad distribution and high local density. In contrast, for parasitic organisms, the trade-off hypothesis predicts that parasites exploiting many host species will achieve lower mean abundance on those hosts than more host-specific parasites because of the costs of adaptations against multiple defense systems. We test these alternative hypotheses with data on host specificity and abundance of fleas parasitic on small mammals from 20 different regions. Our analyses controlled for phylogenetic influences, differences in host body surface area, and sampling effort. In most regions, we found significant positive relationships between flea abundance and either the number of host species they exploited or the average taxonomic distance among those host species. This was true whether we used mean flea abundance or the maximum abundance they achieved on their optimal host. Although fleas tended to exploit more host species in regions with either larger number of available hosts or more taxonomically diverse host faunas, differences in host faunas between regions had no clear effect on the abundance-host specificity relationship. Overall, the results support the resource breadth hypothesis: fleas exploiting many host species or taxonomically unrelated hosts achieve higher abundance than specialist fleas. We conclude that generalist parasites achieve higher abundance because of a combination of resource availability and stability.     

Host traits,identity, and ecological conditions predict consistent flea abundance and prevalence on free-living California ground squirrels

Understanding why some individuals are more prone to carry parasites and spread diseases than others is a key question in biology. Although epidemiologists and disease ecologists increasingly recognize that individuals of the same species can vary tremendously in their relative contributions to the emergence of diseases, very few empirical studies systematically assess consistent individual differences in parasite loads within populations over time. Two species of fleas (Oropsylla montana and Hoplopsyllus anomalous) and their hosts, California ground squirrels (Otospermophilus beecheyi), form a major complex for amplifying epizootic plague in the western United States. Understanding its biology is primarily of major ecological importance and is also relevant to public health. Here, we capitalize on a long-term data set to explain flea incidence on California ground squirrels at Briones Regional Park in Contra Costa County, USA. In a 7 year study, we detected 42,358 fleas from 2,759 live trapping events involving 803 unique squirrels from two free-living populations that differed in the amount of human disturbance in those areas. In general, fleas were most abundant and prevalent on adult males, on heavy squirrels, and at the pristine site, but flea distributions varied among years, with seasonal conditions (e.g., temperature, rainfall, humidity), temporally within summers, and between flea species. Although on-host abundances of the two flea species were positively correlated, each flea species occupied a distinctive ecological niche. The common flea (O. montana) occurred primarily on adults in cool, moist conditions in early summer whereas the rare flea (H. anomalous) was mainly on juveniles in hot, dry conditions in late summer. Beyond this, we uncovered significantly repeatable and persistent effects of host individual identity on flea loads, finding consistent individual differences among hosts in all parasite measures. Taken together, we reveal multiple determinants of parasites on free-living mammals, including the underappreciated potential for host heterogeneity – within populations – to structure the emergence of zoonotic diseases such as bubonic plague.     

Seasonal and among‐site variation in the occurrence and abundance of fleas on California ground squirrels (Otospermophilus beecheyi)

An improved understanding of the ecology of fleas on California ground squirrels, Otospermophilus beecheyi, is warranted given the role of fleas in the transmission, and perhaps persistence, of the plague‐causing bacterium Yersinia pestis. We sampled O. beecheyi on a seasonal basis from three study sites, each representing a different land use type (preserve, pasture, and agriculture) in the San Joaquin Valley, CA. Overall, the abundance of fleas on squirrels was greatest in spring at the preserve site, in summer at the agriculture and pasture sites, and in winter at the pasture site. Hoplopsyllus anomalus, the species most frequently found on squirrels, was most abundant in spring at the preserve site and in summer at the agriculture and pasture sites. Oropsylla montana was most abundant in winter at the pasture site and on adult squirrels. Echidnophaga gallinacea was most abundant in fall on juvenile squirrels at the preserve site. All three flea species we encountered are known to be potential vectors of Y. pestis. Future efforts to predict flea species occurrence and abundance (and plague risk) at sites of concern should consider seasonal microclimatic conditions and the potential influence of human land use practices.     

Trait‐based and phylogenetic associations between parasites and their hosts: a case study with small mammals and fleas in the Palearctic

We investigated the associations between ecological (density, shelter structure), morphological (body mass, hair morphology) and physiological traits (basal metabolic rate) of small mammals and ecological (seasonality of reproduction, microhabitat preferences, abundance, host specificity) and morphological (presence and number of combs) traits of their flea parasites that shape host selection processes by fleas. We adapted the extended version of the three‐table ordination and linked species composition of flea assemblages of host species with traits and phylogenies of both hosts and fleas. Fleas with similar trait values, independent of phylogenetic affinities, were clustered on the same host species. Fleas possessing certain traits selected hosts possessing certain traits. Fleas belonging to the same phylogenetic lineage were found on the same host more often than expected by chance. Certain phylogenetic lineages of hosts harbored certain phylogenetic lineages of fleas. The process of host selection by fleas appeared to be determined by reciprocal relationships between host and flea traits, as well as between host and flea phylogenies. We concluded that the connection between host and flea phylogenies, coupled with the connection between host and flea traits, suggests that the species compositions of the host spectra of fleas were driven by the interaction between historical processes and traits.     

云南省玉龙鼠疫疫源地野外鼠形动物寄生蚤丰盛度影响因素分析

【目的】分析云南省玉龙鼠疫疫源地野外鼠形动物寄生蚤丰盛度的影响因素。【方法】选取云南省玉龙鼠疫疫源地3个海拔区域,按4个季节进行野外捕鼠,捕获的鼠形动物用梳检法收集体表寄生蚤并在显微镜下分类鉴定。通过实际测量和实地观察相结合的方式收集潜在影响鼠形动物寄生蚤丰盛度的因素包括鼠形动物特征变量指标(如种类、年龄、性别、体长、体重)、环境和气象因子(如海拔、季节)等数据。采用EpiData 3.02软件建立数据库,在R软件下使用跨栏负二项分布回归分析鼠形动物寄生蚤丰盛度的影响因素。【结果】从捕获的884只鼠形动物中检获寄生蚤9种484头,以特新蚤指名亚种、方叶栉眼蚤、无值大锥蚤、云南栉眼蚤为主(86.16%)。回归分析显示： 2 700-3 000 m和3 000 m以上海拔鼠形动物染蚤概率较2 400-2 700 m分别增加1.27和3.72倍;湿度高于70%时,鼠形动物染蚤概率较湿度≤70%时减少41%;与齐氏姬鼠的染蚤概率相比,中华姬鼠的染蚤概率降低50%,大绒鼠的染蚤概率增加79%;体长超过104 mm的鼠形动物染蚤概率较体长≤104 mm的鼠形动物染蚤概率增加76%;气温高于15℃时,鼠形动物染蚤数量较温度≤15℃时降低67%;成年鼠形动物的染蚤数量较未成年鼠形动物的染蚤数量增加2.25倍;与春季相比,夏季的染蚤数量增加2.00倍,秋季的染蚤概率减少48%,冬季的染蚤概率和染蚤数量分别增加1.44和1.06倍。【结论】玉龙鼠疫疫源地野外鼠形动物寄生蚤以特新蚤指名亚种、方叶栉眼蚤、无值大锥蚤、云南栉眼蚤为优势蚤种。鼠形动物寄生蚤丰盛度与海拔、季节、气温、湿度等环境气象因子及鼠形动物种类、体长、年龄等鼠形动物特征变量密切相关。     

Factors influencing the breeding of the rabbit flea (Spilopsyllus cuniculi): A spring-time accelerator and a kairomone in nestling rabbit urine with notes on Cediopsylla simplex, another "hormone bound" species

Accelerated impregnation and maturation of the rabbit flea coincides with the spring peak litter-size of the rabbit, but its breeding performance falls off before that of the domestic host. A kairomone nestling factor, which boosts copulation, impregnation and development of fleas feeding on the newborn young, is also present in relatively feeble amounts in baby rabbit urine. This urine boosts pairing of matured (="primed") fleas united in tubes away from a host, but impregnation is increased only if fleas are feeding on newborn young while exposed to the urine.
Undeveloped fleas matured on the pregnant doe require a transfer to another host before they will pair, whereas fleas matured on the nestlings copulate without a transfer. A variable time-lag between transfer and copulation of fleas, dependent on the "priming" qualities of the preparatory host, suggests that a chemical intermediary is involved.
If the antennae of the females are coated with vaseline, the maturation of these fleas is delayed feeding on nestlings, but not on the prepartum doe. This delay is less marked during the spring acceleration than at other times of the year.
The breeding of a North American species of hare flea ( Cediopsyllu simplex (Baker)) parasitizing Sylvilagus floridanus (Allen) is also controlled by the sex hormones of the host.