首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 671 毫秒
1.
2.
石河子紫泥泉种羊场的典型绢蒿荒漠放牧地作为重要的春秋牧场,承担两季的放牧压力,粪甲虫的活动会对粪便内的种子进行二次传播,此行为对草地植被恢复具有重要意义,为研究粪甲虫对粪便内不同尺寸种子水平、垂直传播距离,确定绢蒿荒漠中粪甲虫的季节性变化及物种多样性特征,于2019年4-10月,在石河子紫泥泉种羊场的典型绢蒿荒漠放牧地牛粪中采集到食粪昆虫14797头,其中捕获粪甲虫分属3科17种,蜉金龟科9种、金龟科7种、粪金龟科1种。6月物种丰富度最高,优势种为红亮蜉金龟。10月个体数量最大,优势种为直蜉金龟。在6和10月进行粪甲虫进驻粪便行为观察试验,结果显示6月粪便放置8 h粪甲虫数量到达高峰,10月粪便放置4 h粪甲虫数量到达高峰。随着粪甲虫进驻粪便时间的延长和数量的增加,粪便分解程度不断提高。粪甲虫对粪便中种子的分配与种子大小有关。以小(1.3 mm)、中(3.6 mm)、大(5.8 mm)3种尺寸的珠子作为种子模拟物。结果显示,80%的种子模拟物被埋藏在水平距离20 cm以内及0~10 cm的土壤深度中。有20%的种子模拟物被粪甲虫埋藏到10 cm以下或移动到水平范围20 cm以外。随着种子模拟物大小的增加,埋入种子模拟物的比例逐渐降低。研究结果显示粪甲虫对粪便内种子的二次传播有助于绢蒿荒漠的生态恢复。  相似文献   

3.
An involvement of Pilobolus species fungus in the dispersal of Dictyocaulus viviparus third stage larvae from dung to surrounding herbage under Irish conditions was investigated. The presence of Pilobolus kleinii on artificial dung pats containing first stage larvae of D viviparus was associated with a 19-fold increase (P less than 0.05) in numbers of third stage larvae recovered from the surrounding herbage. A subjective examination of natural dung pats showed that the presence of Pilobolus species was significantly correlated with hours of bright sunshine (r = -0.5, P less than 0.01), total rainfall (r = 0.41, P less than 0.05) and the height of herbage surrounding the pats (r = 0.31, P less than 0.001). A multiple regression analysis showed that meteorological parameters and the height of surrounding herbage accounted for 38 per cent of the variation in growth of Pilobolus species on dung pats. The incidence of extensive damage to natural dung pats within five days of deposition, caused by biotic factors, another possible cause of D viviparus third stage larvae dispersal, varied from 0 to 92 per cent of the pats depending on their degree of dryness.  相似文献   

4.
Culicoides (Avaritia) loxodontis sp. nov., is described and illustrated from both sexes collected in South Africa. It is the 5th species of the Imicola group of the subgenus Avaritia to be described from the Afrotropical Region, and is presently known only from the Kruger National Park where it has been collected in light-traps and reared from the dung of the African elephant (Loxodonta africana) on various occasions. A number of character states, and statistical analyses of antennal and palpal measurements, are used to separate the new species from its taxonomic congeners C. imicola Kieffer, 1913, C. pseudopallidipennis Clastrier, 1958, C. bolitinos Meiswinkel, 1989 and C. miombo Meiswinkel, 1991. It is suggested that the occurrence of the African elephant is the primary factor that determines the distribution of Culicoides loxodontis sp. nov., and that this close association, coupled with the fact that C. loxodontis sp. nov. can be locally abundant, may result in the cycling of certain arboviruses between this biting midge and the elephant.  相似文献   

5.
The viruses causing the economically important livestock diseases of African horse sickness (AHS) and bluetongue (BT) are transmitted by biting midges of the genus Culicoides (Diptera, Ceratopogonidae). In the Old World the most important vectors of these diseases are Culicoides imicola Kieffer, 1913, Culicoides brevitarsis Kieffer, 1917 and Culicoides bolitinos Meiswinkel, 1989. All three of these vectors belong to the Imicola complex of the subgenus Avaritia Fox, 1955. This species complex now comprises 12 sibling species; ten occur in sub-Saharan Africa and are difficult to identify (based mostly on subtle variations in the wing latterns) and so additional methods of reliable identification are needed. The pupal exuviae of the five commonest sibling species (C. imicola, C. bolitinos, Culicoides loxodontis Meiswinkel, 1992, Culicoides tuttifrutti Meiswinkel, Cornet & Dyce, 2003 and Culicoides sp. # 107) harvested from a variety of large herbivore dung types and from decaying fruits, are described and illustrated in detail. It is shown that they can be differentiated clearly on a number of morphological characters and, furthermore, are separable into two distinct groups based (principally) on the shape of the respiratory organ. A key for identifying and differentiating these five pupae is provided. Also, the pupa of the Oriental-Australasian C. brevitarsis was compared with its allopatric sister taxon, C. bolitinos. Because they share a common larval habitat (cattle and buffalo dung) and are almost inseparable in the adult phenotype, the question of their possible synonymy is raised. However, their respective pupae could not be differentiated on gross morphology and so it is argued that this unresolved problem requires a molecular solution.  相似文献   

6.
利用mtD NA的Cyt b基因全序列对39个鼩鼱属物种的系统分化进行分析,其中包括我国东北地区具有的9个鼩鼱属物种。计算了遗传距离和构建了系统进化树。分子系统学分析支持鼩鼱属应该分为主要分布于古北区的亚属和主要分布于新北区的亚属。Sorex亚属包括分布在古北区的鼩鼱属物种和分布在全北区的苔原鼩鼱和姬鼩鼱,以及分布在新北区的北极鼩鼱。Otisorex亚属包括分布在新北区的鼩鼱属物种和分布在古北区的堪察加鼩鼱和弗兰格尔鼩鼱。特氏鼩鼱-索绪尔鼩鼱类群高度特化,支持其与Otisorex亚属具有更近的系统进化关系。本文探讨了我国东北地区具有的9个鼩鼱属物种的系统分化和分类学问题,进而明确了其在鼩鼱属的系统发生地位。支持姬鼩鼱为全北区物种。扁颅鼩鼱在系统发生地位上较为特化。支持栗齿鼩鼱属于XY_1Y_2性染色体复杂种组。大鼩鼱是东北分布的鼩鼱属物种中最特化的一个物种。我国东北分布和日本北海道分布的细鼩鼱属于不同亚种。  相似文献   

7.
甘肃境内鼢鼠Eospalax亚属分子系统发育研究   总被引:1,自引:0,他引:1  
为了筛选评价甘肃境内鼢鼠凸颅亚属母性遗传多样性分子标记,研究该亚属的分子系统发育。测定了分布于甘肃11个不同地方31只属于鼢鼠中凸颅亚属的不同鼢鼠,其中包括:9只高原鼢鼠、9只甘肃鼢鼠、9只斯氏鼢鼠、4只秦岭鼢鼠的细胞色素b基因全序列1 140 bp。从GenBank获得包括平颅亚属在内的21个细胞色素b全序列总共52条全序列,用MEGA软件分别绘制出本研究的31条全序列和总共52条全序列的2个系统发育树。运用测定序列,结合相关软件分析31条细胞色素b基因全序列的变化特征;分析和探讨本试验的Eospalax亚属4个种的分类及系统发育。本研究为鼢鼠的系统发育提供了分子理论依据。  相似文献   

8.
Seeds of many plant species are secondarily dispersed by dung beetles, but the outcome of this interaction is highly context‐specific. Little is known about how certain anthropogenic disturbances affect this plant–animal interaction. The aims of this study were to assess the effect of dung type on secondary dispersal by dung beetles in a forest fragment, and to determine whether this interaction is affected by edge effects. Using pitfall traps, we captured dung beetles attracted to dung of 2 frugivorous mammals: woolly monkeys and howler monkeys. We found differences between both dung beetle assemblages, but these differences were not consistent in time. Using seeds surrounded by both dung types, we carried out a field experiment using seeds of 2 plant species. We found that the probability of secondary dispersal by dung beetles was higher for seeds placed in woolly monkey dung. Finally, we carried out a field experiment using plastic beads as seed mimics to assess edge effects. We found that secondary seed dispersal by dung beetles was negatively affected by edges. The disruption of plant–animal interactions along anthropogenic forest edges could have long‐term negative effects on forest dynamics by affecting processes of regeneration.  相似文献   

9.
Plant litter and livestock excreta are two important ways of carbon and nutrient input to soil in grassland grazing systems. Grazing livestock often deposit dung on plant litter, which may affect litter decomposition through a changing microenvironment. We assessed effects of yak dung on litter mixing effects on litter decomposition in a Tibetan alpine grassland. Six common species were selected, including low-quality litter species Kobresia capillifolia, Elymus nutans, and Ligularia virgaurea and high-quality litter species Anemone rivularis, Saussurea nigrescens, and Thermopsis lanceolata. Litter bags containing each species alone and all two-species combinations were allowed to decompose with and without experimental dung addition in the field. Mass loss of the leaf litter was measured after 6 and 12 mo. High-quality litter species had significantly greater mass loss than low-quality litter species. Dung significantly accelerated litter mass loss after both 6 and 12 mo for low-quality litter species, but only after 12 mo for high-quality litter species. Litter mixtures containing both high- and low-quality species showed positive nonadditive effects (NAEs) on mass loss after 6 mo but additive effects after 12 mo. Dung increased the strength of NAEs after 6 mo and shifted litter mixing effects from positive to negative NAEs after 12 mo. Our results support previous findings that litter mixing could produce NAEs on litter decomposition and that these NAEs could change with incubation time. Most importantly, we show that dung can modify NAEs, demonstrating that litter mixing effects are dependent on the microenvironment. Our findings also demonstrate that yak dung can influence soil processes by varying both single-species litter decomposition rates and litter interactions within mixtures. Furthermore, the results suggest yak dung is closely related to material and nutrient cycling, so we believe dung should remain and not be substantially removed from this grazing ecosystem.  相似文献   

10.
Ecology of Rhodococcus equi   总被引:7,自引:0,他引:7  
A selective broth enrichment technique was used to study the distribution of Rhodococcus equi in soil and grazing animals. Rhodococcus equi was isolated from 54% of soils examined and from the gut contents, rectal faeces and dung of all grazing herbivorous species examined. Rhodococcus equi was not isolated from the faeces or dung of penned animals which did not have access to grazing. The isolation rate from dung was much higher than from other samples and this was found to be due to the ability of R. equi to multiply more readily in dung. Delayed hypersensitivity tests were carried out on horses, sheep and cattle, but only horses reacted significantly. The physiological characteristics of R. equi and the nature of its distribution in the environment suggested that R. equi is a soil organism.  相似文献   

11.
Dung beetles are considered keystone species because of their role in decomposition, seed dispersal, and control of vertebrate parasites in grazed habitats. Despite the ecological importance of this group to pasture ecosystem functioning, still little is known about its relationship with grazing management activities. We evaluated the conservation value of protected areas for dung beetle diversity by comparing two different management conditions of Mediterranean savanna in central Spain. Four different sites with wild herbivory (red deer, roe deer) were sampled inside the Cabañeros National Park, and four sites with traditional agrosilvopastoral management were sampled in a sheep farm near the park. The dung beetle species richness was similar between savanna conditions, but the total dung beetle abundance and biomass were considerably greater in the park grasslands than in the grasslands of the sheep farm. Dung beetle species composition, species dominance, and abundance by functional groups from both park and farm sites were different, despite the high similarity among the sampled sites in both hydric content and dung availability. Onthophagus maki (Illiger 1803) and O. furcatus (Fabricius 1781) were the dominant species in the park, while O. furcatus, Aphodius foetidus (Herbst 1783), and Caccobius schreberi L. were the dominant species on the farm. Species richness and abundance of telecoprids were higher in the park than on the farm. Abundance of paracoprids was also higher in the park than on the farm, while no differences in species richness and abundance of endocoprids were observed between both conditions. These results suggest that management activities such as plowing and the use of veterinary substances affect soil structure and dung quality and could be important factors that alter dung beetle assemblages in terms of composition, abundance, and biomass on traditional farms.  相似文献   

12.
史威威  张佩  张涛 《草地学报》2018,26(4):959-963
为研究羊粪对燕麦(Avena sativa)种子萌发特性的影响,以不同浓度羊粪浸提液(0、25%、50%、75%、100%)处理的7个品种(‘燕王’、‘牧王’、‘爱沃’、‘枪手’、‘魅力’、‘领袖’和‘贝勒’)的燕麦种子进行萌发试验。结果表明:100%羊粪浸提液显著抑制枪手的发芽率(P<0.05),其他6个品种燕麦种子发芽率没有受羊粪浸提液的影响;羊粪浸提液显著降低‘牧王’、‘魅力’、‘领袖’和‘贝勒’的发芽势(P<0.05),且随着浸提液浓度的升高,种子发芽势逐渐降低;随着浸提液浓度的升高,各品种燕麦种子的发芽指数均有逐渐降低的趋势;100%浓度浸提液显著降低种子活力指数(P<0.05),而50%浸提液能显著提高‘燕王’、‘牧王’、‘领袖’和‘贝勒’的活力指数(P<0.05)。  相似文献   

13.
Objective To assess the toxicity to insects of drug residues excreted in cattle faeces following treatment with deltamethrin.
Design Bioassays were performed on one species of dung-breeding fly ( Musca vetustissima ) and two species of dung beetle ( Onthophagus binodis and Euoniticellus fulvus ).
Animals Cattle on properties near Kangaroo Valley, Canberra and Gundagai were treated with pour-on formulations of deltamethrin. Untreated animals acted as controls.
Procedures Faeces from treated and untreated cattle were inoculated with newly emerged fly larvae or fed to adults of two species of dung beetle. Percentage survival and duration of development provided measures of the toxicity of deltamethrin residues in faeces.
Results Residues of deltamethrin were excreted in concentrations sufficient to inhibit survival of larvae of M vetustissima for 1 to 2 weeks after treatment. Peak concentrations of 0.4mg deltamethrin/kg dry weight of faeces occurred 3 days after treatment and were sufficient to kill adult beetles for at least twice this period. With one of two formulations tested, there was evidence of a reduction in dung beetle fecundity and an increase in the duration of juvenile development. A model of the effect of deltamethrin on the breeding success of dung beetles in the field suggests that a single treatment, applied when most of the population is in a non-parous condition, may cause up to 75% reduction in beetle acitivity by the end of the season. Multiple treatments at 10 or 21 day intervals may drive local populations towards extinction.
Conclusion Depending on the time and frequency of treatment, the effect of deltamethrin on insects in cattle faeces may range from negligible to catastrophic.  相似文献   

14.
Rangeland dung beetles represent an important assemblage of insects for the Great Plains. In this study, we examine the effects of a postfire rangeland environment on a dung beetle assemblage in north-central Texas. We deployed baited pitfall traps to examine spring prescribed fire treatment, differences in vegetation visual obstruction, and dung density influence on dung beetle abundance and community composition. Using model-based multivariate methods, we did not find an influence of prescribed burning on the dung beetle assemblage. We report a negative influence of vegetation visual obstruction and no significant influence of dung density on dung beetle assemblages. These results suggest that prescribed fire may not negatively affect dung beetle species within the North American Great Plains; however, vegetation structure correlated to postfire rangeland environments may influence local beetle abundance.  相似文献   

15.
牦牛粪沉积下高寒草甸植物群落种间关联研究   总被引:1,自引:0,他引:1  
植物群落构成和种间关联,反映物种在空间上的分布及相互依存和制约关系。为探究牦牛粪沉积和植被斑块互作下草地植物群落演变趋势及稳定性机制,以青藏高原东北缘高寒草甸禾草/杂类草斑块和嵩草/杂类草斑块为对象,分析牦牛粪沉积下两种斑块中主要植物种的重要值(IV)、Jaccard种间关联指数和Spearman秩相关系数的变化规律。结果表明,1)粪沉积使禾草/杂类草斑块的建群种扁穗冰草的IV增加和西北针茅的IV降低,嵩草/杂类草斑块的建群种线叶嵩草的IV降低;2)禾草/杂类草斑块中,粪沉积(DP)和对照(CK)的正负关联种对比为0.61和0.63,显著联结种对为6.6%和6.4%;嵩草/杂类草斑块中,DP和CK的正负关联种对比为0.90和0.72,显著联结种对为2.8%和14.5%;且二者显著联结的种对多存在于优势种或亚优势种与伴生种之间;3)两种斑块中多数种对间联结性弱,群落处于不稳定阶段;粪沉积使嵩草/杂类草斑块的稳定性增强,利于禾草/杂类草斑块的演变;4)依据优势种对环境的适应方式和主导生态因子,将两种斑块的群落植物种划分为喜阳耐旱植物、喜阴喜湿植物和喜阳喜湿植物三大生态种组。  相似文献   

16.
SUMMARY Observations were made on the identity and activities of coprophagous arthropods in horse faeces at Moggill in southern Queensland. A number of families of arthropods were represented, but of these only members of the Scarabaeidae were involved in the dispersal of the faecal mass. Six species of indigenous dung beetles, all of the genus Onthophagus, utilised horse faeces as a food source. One of these, O granulatus, was present in large numbers, but it was unable to achieve complete dispersal of equine faecal masses. The introduced Afro-Asian dung beetle Onthophagus gazella is also well established at Moggill, and uses horse faeces as a food source. Unlike the indigenous species, this beetle is able to achieve complete breakdown of the structure of horse faecal masses in one night, leaving the fibrous remnants on the soil surface. However, this level of activity was restricted to the warmer months, from November to March, with faeces remaining largely undisturbed for the remainder of the year. It was noted that heavy rain also reduced the activity of dung beetles. A comparison was made between the recovery of infective strongyle larvae from herbage near faecal masses exposed to dung beetle activity, and from control faecal masses from which beetles were excluded by insect mesh envelopes. Reductions in recovery of the order of 60% were recorded at the peak of O. gazella activity in summer, but since much less reduction occurred for the remainder of the year, it was concluded that dung beetles are of little benefit in the control of equine strongylosis, in the absence of other measures to reduce pasture contamination.  相似文献   

17.
While resistance against many other classes of acaricides has been described, products containing benzoylphenyl urea are currently still successfully used against the pesticide-resistant blue tick (Boophilus decoloratus) in South Africa. In order to assess any adverse impact of these tickicides on the important dung beetle (Coleoptera: Scarabaeidae) fauna, a bioassay was undertaken on the ecotoxicological effects of a fluazuron (benzoylphenyl urea) pour-on formulation (Acatak) on the survival and reproduction of the African dung beetles species Onthophagus gazella (Fabricius). The experiment yielded no significant differences in adult or larval survival, egg production, fecundity and fertility between the control and treatment group following three beetle generations over. These results suggested that treatment of cattle with the fluazuron pour-on formulation Acatak was not detrimental to the selected dung beetle species in any notable way.  相似文献   

18.
A field trial was conducted to assess the rate at which dung becomes infested by fungi which parasitise nematodes (nematophagous fungi) after deposition. Sheep dung was placed on field plots of bare ground, ryegrass (Lolium perenne), browntop (Agrostis capillaris) and white clover (Trifolium repens) in summer (February) and autumn (April), and subsamples were examined at intervals for the presence of nematophagous fungi. Nematophagous fungi occurred in 71% of 129 samples recovered in February and 57% of 58 samples recovered in April. Arthrobotrys oligospora, Monacrosporium candidum and Nematoctonus spp. were the most frequently isolated nematode-trapping fungi in both seasons. The endoparasitic nematophagous fungus Harposporium leptospira also occurred frequently in dung deposited in February, but not April. Fungi entered dung quickly, with 83% and 58% of dung samples containing nematophagous fungi at 3 days after deposition in February and April, respectively. The percentage of dung infested by nematophagous fungi on plots of bare ground, ryegrass, white clover and browntop was 76%, 75%, 61% and 55%, respectively. Results suggest that a number of species of nematophagous fungi are able to enter dung soon after deposition on a variety of types of ground cover.  相似文献   

19.
According to European Union recommendations, a test method has been developed to evaluate the effects of veterinary pharmaceuticals on dung feeding insects. This test method was evaluated with the dung beetle Aphodius constans by using fecal residues of ivermectin after a pour-on administration. Dung of different age (and thus containing different concentrations of ivermectin) as well as mixtures of highly-contaminated spiked dung with untreated control dung were studied in five test runs in two laboratories. The concentration of ivermectin (active substance; a.s.) in the dung samples was verified analytically. The main test endpoint was the survival of first instar larvae. The LC50 using dung directly obtained from treated cattle ranged from 470 to 692 microg a.s. kg(-1) dung (dry weight; d.w.) and 67 to 97 microg a.s. kg(-1) dung (fresh weight; f.w.). Using mixtures, the outcome of two tests was almost identical: 770 to 781 microg a.s. kg(-1) dung (d.w.); 109 to 132 microg a.s. kg(-1) dung (f.w.). In comparison to the LC50 values obtained when ivermectin was spiked in control dung at several concentrations (LC50 880-985 microg a.s. kg(-1) dung (d.w.)), the LC50 values were again very similar. Three conclusions can be drawn from these results. The proposed test method seems to be robust and allows for the initiation of an international validation process (including ringtesting). Because of only small differences found in tests in which the test substance was spiked into control dung and those in which dung from treated cattle was applied, the use of a standard test method is proposed. The effects of ivermectin on ecologically relevant dung beetles obtained in a standardised test method reflect the results from field studies and are in the range of environmentally relevant concentrations.  相似文献   

20.
Objective To evaluate the safety of monepantel and its major metabolite for dung fauna. Monepantel is a new oral anthelmintic drug for use in sheep at a dose of 2.5 mg active ingredient/kg body weight. Hazard (toxicity) is related to the expected exposure. Design The methodology was based on the Organisation for Economic Cooperation and Development (OECD) draft guideline for testing of chemicals, so dung from cattle, not sheep, and eggs of the dung fly, Scathophaga stercoraria and larvae of the dung beetle Aphodius constans were used. Procedures Monepantel or its sulfone metabolite were mixed into bovine faeces in which either dung fly eggs or dung beetle larvae were placed and their development observed. The primary endpoint was survival. Real exposure data (faecal concentrations) for comparison with the generated laboratory data were taken from a kinetics study in sheep dung. Results The no-observed effect concentration (NOEC) for monepantel was >1000 mg/kg substrate for dung flies and 250 mg/kg for dung beetles. The sulfone metabolite was slightly more toxic, with a NOEC of 500 mg/kg for dung flies and 125 mg/kg for dung beetles. Conclusion A comparison of the results to the maximum concentrations of 15 mg monepantel and 4.5 mg sulfone per kg dung observed under an exaggerated dosing regime in sheep indicates that monepantel poses no risk to insect dung fauna when used as recommended. The study is considered valid because representatives of both genera were able to develop in bovine or ovine dung.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号