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1.
Mites in the genus Chorioptes cause a mild form of skin disease in both domestic and wild ruminants. In July 2006, dermatitis characterized by alopecia, marked lichenification, accumulation of crust, and fissuring was recognized in 14 out of 200 Holstein dairy cattle raised in the cattle farm of the National Institute of Animal Science in Cheonan, Republic of Korea. Skin lesions were distributed mainly over the tail base, and sacral and perineal regions. Microscopic examinations of skin scraping samples from severely affected areas revealed numerous mites of all developmental stages. Morphologically, pedicels of the mites were short and unjointed. The tarsal suckers occurred on the pedicels of all the legs in the male worm and on the first, second, and fourth pair of legs in the adult female worm. A single long seta at the tarsus of legs III and the length of legs II being about twice as long as legs IV in adult male mites were observed. Arising anterior to the inner-most spatulate seta was a short seta with an average of 26.4 ± 5.8 µm in length. Also, the length of setae #4 on the opisthosomal lobes was relatively short. Based on these observations, the mites were identified as Choriptes texanus. Although the chorioptic mange may not influence the mortality rate in the affected farm, reports indicate that a decline in milk production can be observed. This is the first report of chorioptic infestation in a cattle farm from Korea.  相似文献   

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This study is the first comprehensive documentation of the geographical range of Anguillicola crassus in its host, the European eel Anguilla anguilla, in the Republic of Ireland. The prevalence and intensity of infections across 234 sites and 93 river basins in Ireland comprising rivers, lakes and transitional waters (estuaries) were analysed. While only 32% of the river basins were affected by this nematode, they correspond to 74% of the total wetted area. Significant differences in infection levels among water body types were found with lakes and transitional waters yielding the highest values, which can be attributed to the proportions of juvenile (total length, LT < 300 mm) A. anguilla caught. There were no significant differences in infection levels between water body types for adult A. anguilla or between sexes for any water body type. Prevalence was significantly lower in juvenile compared with adult A. anguilla captured in rivers and a positive correlation between infection levels and host size‐classes was found. Future efforts should focus on monitoring the spread of A. crassus infections and assessing the swimbladder health of A. anguilla in Ireland.  相似文献   

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We describe the adult and metacercaria of a new species of digenetic trematode, Stephanostomum lophii sp. nov., an intestinal parasite of the angler fish, Lophius piscatorius . The species is distinguished from the similar Stephanostomum kovalevi by the numerous peristomial spines in the latter and from S. baccatum by the oral sucker being larger than the ventral sucker and by the fact that the principal intermediate hosts are gadids, not pleuronectids as in the case of Stephanostomum baccatum . We also report the prevalence of S. lophii metacercariae in various potential angler fish prey species caught off the coast of Galicia (NW Spain).  相似文献   

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Baseline information on the parasites of frequently caught species of the characids namely Hydrocynus vittatus , Alestes baremoze , Brycinus macrolepidotus and Brycinus leuciscus was investigated in Anambra River from August 2004 to July 2005. The parasites recovered were the Myxosporid, Myxobolus sp (Protozoa), Polyopistocotylids, Diplozoon ghanense and Neodipolzoon polycotyleus (Monogeneans), the Caryophyllid Caryophylleus sp (Cestoda) and Rhabdochona sp (Nematoda). The prevalence of Caryophylleus sp in B. macrolepidotus (14.2%) and A. baremoze (8.1%) as well as Rhabdochon sp and Myxobolus sp in H . vittatus (9.6% and 7.8% respectively) was relatively high (>7.0%); while the other parasite species Myxobolus sp in B. leuciscus (2%), D. ghanense in B. macrolepidotus (1.9%) and N. polycotyleus in A. baremoze (1.9%) had a much lower prevalence (2.7%). Distribution of parasites was clearly seasonal. Dissolved oxygen (8.0–14.0) mg l−1 and pH (5.5–7.0) influenced the occurrence of the parasites whereas temperature (20.1–27.5 DC) showed no much effect.  相似文献   

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本研究旨在揭示印度查谟柑桔潜叶蛾Phyllocnistis citrella Stainton为害甜橙Citrus sinensis的季节性变化,以及降雨量、相对湿度和温度等重要的气候因子对其种群的影响。本文对不同季节印度查谟的一个甜橙园里的柑桔潜叶蛾丰度进行了调查, 从2005年3月到2008年2月每两周调查一次。柑桔潜叶蛾在一年内有3个为害高峰,分别是4月中旬、7月中旬和9月中旬,这与甜橙新营养梢的生长期相吻合。相关分析表明,上午和下午的相对湿度和平均相对湿度与柑桔潜叶蛾的数量呈负相关;然而,平均降雨量、最高气温、最低气温和平均气温与柑桔潜叶蛾的数量呈正相关。降雨量和温度与柑桔潜叶蛾为害程度呈显著正相关。总之,柑桔潜叶蛾的数量不能简单地通过观察某一特殊地区的相对湿度来预测,而降雨量和温度在影响虫害方面均起着重要的作用。  相似文献   

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Snails of the genus Lymnaea are morphologically variable and their taxonomy is unclear. In particular, the forms peregra and ovata , distinguished by shell shape, are often considered variants of the same species, L. peregra. We studied a rare situation in a Swiss mountain lake where both forms are sympatric. First, we found that the forms shows complete separation for a number of allozymes. Second, we examined the response of the two snail forms to infection by the trematode Diplostomum phoxini . For the ovata form, there was a transitory, 10% increase in the growth of infected snails compared to uninfected controls. The peregra form showed no gigantism and had higher parasite-induced mortality. Third, we assessed differences between the forms in reproduction under different environmental conditions. Density negatively influenced egg production to the same degree in both forms. However, decreasing water levels, characteristic of part of the lake studied, led to a 30% decrease in egg production for the ovata form, but only a 10% decrease for the peregra form. These differences are discussed in relation to the microdistributions of the snails in the lake and we conclude that the two forms are almost certainly separate species.  相似文献   

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Fruit flies (Diptera: Tephritidae) are dipteran insects that cause high losses of fruits and vegetables in the tropical and subtropical regions of the world. As quarantine pests, fruit flies affect export markets because trade regulations hamper export of fruits from areas with occurrence of fruit flies. We compared the effectiveness of Oecophylla longinoda with the insecticide; imidacloprid for the control of Bactrocera dorsalis in a 6-year-old orchard of mango cultivar ‘Apple’. Mango samples at different developmental stages were collected between September and November in 2012 and between November 2013 and January 2014 at a three-week interval between sampling dates. Every fruit was cultured in a separate individual plastic container containing approximately 500?g sieved sterilised sand. Three weeks later, larvae and pupae were sieved from sand and counted. In both years, significantly higher (P?<?.0001) incidences and infestation rates were recorded in the control plots when compared to the trees protected with insecticides and O. longinoda. Incidences and infestation rates did not differ significantly (P?>?.05) between insecticide and weaver ants protected fruits, implying that O. longinoda was as effective as imidacloprid in suppressing the population of fruit flies. Peak fruit fly incidences and infestation rates coincided with the ripening stage of mango fruits. Our results have shown that the incidences and infestation rates on incubated mango fruits were lowest in the O. longinoda and the imidacloprid protected trees. Thus, O. longinoda is an effective bio-control agent that could be exploited to serve as a vital Integrated Pest Management component on mango orchards.  相似文献   

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Concurrent infections with vector-borne pathogens affected a cattle herd in Switzerland, and one of the pathogens was identified as Babesia bigemina, which had never been observed in this country before. Therefore, a survey of the occurrence of ruminant Babesia spp. and their tick vectors in Switzerland was conducted. A total of 2,017 ticks were collected from sheep, goats, cattle, and wild ruminants (deer, roe deer, and chamois) in southern parts of Switzerland and identified morphologically. The vast majority of the ticks (99.2%) were Ixodes ricinus, but 14 ticks from sheep and goats were identified as Dermacentor marginatus and two ticks from wild ruminants were identified as Hemaphysalis punctata. PCR analyses of 700 ticks revealed the presence of Babesia divergens (n = 6), Babesia sp. genotype EU1 (n = 14), and B. major (n = 2), whose suggested occurrence was confirmed in this study by molecular analysis, and the presence of novel Babesia sp. genotype CH1 (n = 4), which is closely related to B. odocoilei and to Babesia sp. genotype RD61 reported from North America. The identification of B. divergens and B. major in ticks collected from wild ruminants cast doubt on the postulated strict host specificity of these bovine Babesia species. Furthermore, the zoonotic Babesia sp. genotype EU1 was detected in ticks collected from domestic animals but was obtained predominantly from ticks collected from wild ruminants. More than one tick containing DNA of different Babesia spp. were collected from two red deer. Hence, the role of these game animals as reservoir hosts of Babesia spp. seems to be important but requires further investigation.  相似文献   

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Psoroptes mites are obligate ectoparasites of mammals that cause psoroptic mange in a number of domestic and wildlife species world-wide. Correct identification of species in this genus is important for eradication and quarantine programs. However, conflicting reports about species identity and host specificity within this morphologically conservative genus have raised questions regarding the usefulness of the taxonomic characters previously used to distinguish species. Records that rely only on host species do not provide accurate identification ofPsoroptes mites at the species level. This paper reviews the information available on life history, geographic distribution, and host specificity for this genus, with special reference to problems associated with identifying species in Australia.  相似文献   

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李志文  孙寒松 《昆虫学报》2016,(10):1123-1132
【目的】油茶象Curculio chinensis Chevrolat是我国特有木本油料树种——小果油茶Camellia meiocarpa Hu的专性蛀果害虫,常导致大量落果。在本研究样地,啮齿动物对落果及果内象虫具强烈捕食作用。本研究旨在揭示小果油茶、油茶象和啮齿动物三者间复杂的相互作用及其行为机制,为油茶象科学防控提供理论依据。【方法】2013年在湖南省益阳市赫山区小果油茶林于落果季节系统调查6 161个落果,检查油茶象寄生及啮齿动物捕食情况,并对果长、果径和壳厚进行了测量。用线性回归模型分析象蛀率与果径、壳厚和效费比以及油茶象死亡率与调查日期的相关性;用独立样本t检验分析啮齿动物捕食的象蛀落果与非象蛀落果大小差异性。【结果】象蛀落果2013年7月2日始至果实采收止,具明显高峰期,即同年8月16日至8月23日。啮齿动物捕食贯穿整个落果季节,其高峰期与象蛀落果高峰期一致。象蛀落果中4-5龄幼虫所占比例高达85.5%。油茶象寄生率与果径不相关,与壳厚显著线性负相关,与效费比显著线性正相关。象蛀果实脱落越早,果实发育受限越重,油茶象幼虫死亡率越高。被啮齿动物捕食的油茶果实中,小果实占76.9%,其种子被啮噬殆尽。啮齿动物对象蛀果实的捕食率为24.0%,此类果实中,象蛀种子多破损,非象蛀种子几乎不被捕食。啮齿动物啮噬果实中,象蛀果实的果长和果径均显著大于非象蛀果实的。【结论】本研究明确了研究样地小果油茶落果、象蛀落果及啮齿动物捕食的时间格局。象虫蛀食导致果实发育正常生理活动受阻是油茶果实脱落的根本原因,不支持主动防御假说。油茶象产卵行为在果实大小与壳厚两种矛盾的选择压力间存在权衡,其本质可能是亲代雌虫繁殖力与后代幼虫适合度间的权衡。产卵时间格局通过影响寄主果实发育最终对后代幼虫适合度产生影响。研究样地中,啮齿动物能准确探测并捕食大果实中油茶象幼虫,是油茶象重要的天敌控制因子。  相似文献   

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Israeli theridiid spiders of the genus Enoplognatha are revised. Five species, four of them new, each represented by the two sexes, are recognized, and their affinities with similar species from adjacent regions are discussed. All species previously described from this region have been re-examined. The occurrence of E. mandibularis , formerly reported from Israel, has been confirmed, while the record of E. ovata has proved erroneous. A key to the species is provided.  相似文献   

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The giant grasshopper Tropidacris collaris (Stoll, 1813) (Orthoptera: Romaleidae) is a Neotropical species that causes economic damage to diverse and unrelated crops. We report herein the occurrence of this grasshopper in orchards of dwarf cashew Anacardium occidentale L. (Anacardiaceae) located in the state of Ceará, one of the main cashew‐producing areas of Brazil. Nymphs and adults were observed feeding on cashew leaves during June and July 2016, causing partial or total defoliation of some plants. This report updates the feeding plants of T. collaris and its distribution in Brazil and serves as an early warning of possible future attacks by the pest on cashew orchards in the northeastern region of the country.  相似文献   

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Hybridization experiments between Haemonchus contortus from sheep and H. placei from cattle indicate that the H. placei vulvar morph type and the inability of the eggs to hatch and develop at 11°C were inherited as dominant traits in the hybrids. The size of the third stage larvae was similar to H. placei in hybrids from the mating of male H. placei × female H. contortus while larvae from the reciprocal mating were intermediate in size. Hybrids produced by the mating of thiabendazole resistant female H. contortus × non-resistant male H. placei were also resistant. The F1 males of the mating between male H. contortus and female H. placei were sterile. Male sterility did not occur in the reciprocal cross until the F2 generation. Female hybrids from these generations had a low level of fertility when backcrossed to males of either parent species. Cytological studies of the hybrid males indicated that sterility was due to several kinds of meiotic disturbance and that spermatogenesis stopped during metaphase I. The chromosomes in eggs of unfertilized females did not undergo meiosis and polar body formation; instead they increased in number by a process of endomitosis. Unfertilized eggs in the faeces were characterized by uneven cytoplasmic division and abnormal shape. It is proposed that hybrid sterility can lead to the local eradication of one species of Haemonchus by the other. Furthermore, the outcome of which species is eradicated can be influenced by such variables as initial population sizes, climate, and the local ratio of sheep to cattle.  相似文献   

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