基于18S rRNA基因部分序列探讨四种蛙类多盘科吸虫分类地位

分析了寄生于蛙类膀胱的4种多盘虫科Polystomatidae吸虫:石林双睾吸虫Diplorchis shilinensis、锯腿树蛙多盘吸虫Polystoma carvirostris和分别寄生于昭觉林蛙Rana chaochiaoensis、华西雨蛙Hyla a.annectans的2未定种的分类地位,并利用18S rRNA基因部分序列进行了系统发育重建.结果表明:4种多盘科吸虫为多盘虫属Polystoma和双睾虫属Diplorchis的4个分类单元,其中2未定种为多盘虫属未记录种;肠管、生殖系统、后吸器、大钩和生殖棘等为多盘虫属属内种定种的可靠性状.基于18S rRNA基因序列,4种多盘科吸虫呈现以下进化关系:1)寄生于昭觉林蛙和华西雨蛙的多盘虫属2未定种进入欧非混合进化支;2)锯腿树蛙多盘吸虫位于多盘虫属进化支的最基部;3)石林双睾吸虫进入澳洲进化支.     

中国海产鱼类的扇盘吸虫属的研究

本文记载我国寄生于海产鱼类的扇盘吸虫属 Rhipidocotyle Diesing 1858,共有4种,两种为已有记载的杖形扇盘吸虫R.baculum(Linton,1905)Eckmann,1932与侧杖扇盘吸虫 R.adbaculum Manter,1940, 这两种为我国的新纪录;另两个为新种:大黄鱼扇盘吸虫R.croceae,sp.nov.与棒囊扇盘吸虫 R.clavivesiculum,sp.nov. 。     

寄生于锯腿树蛙多盘吸虫属单殖吸虫一新种记述

记述了锯腿树蛙多盘吸虫Polystoma carvirostris sp.nov.。新种宿主为锯腿树蛙Rhacophorus carvirostris Guenther,1868,采自云南屏边县。新种中央大钩基部截形,国外近似种大钩基部分叉状。新种虫体全长平均5·07mm,体型小于屏边多盘吸虫Polystoma pingbianensis和斑腿树蛙多盘吸虫P.leucomystax。新种肠管内侧盲肠分支多数过腹中线,且于中后部交叉联合成网状;屏边多盘吸虫P.pingbianensis肠管内侧盲肠分支多数过中线,仅1个肠联合;斑腿树蛙多盘吸虫P.leucomystax肠管内侧盲肠分支均过中线,肠联合与分支肠管交错排列。     

寄生于牛蛙的拟后盘属吸虫一新种（复殖目：重盘科）

寄生于广州市郊牛蛙消化道中的一种复殖类吸虫,经鉴定为拟后盘吸虫属一新种,命名为中华拟后盘吸虫。     

黑龙江省扎赉特旗牛羊胰阔盘吸虫病流行病学及病原生物学的研究

一、前言 牛羊胰脏吸虫病是我国各农牧区中常见而且危害严重的一种吸虫病,国内此吸虫病的病原主要有胰阔盘吸虫(Eurytrema pancreaticum(Janson)、腔阔盘吸虫(E.coelomaticum(Giard et Billet)及枝睾阔盘吸虫(E.cladorchis Chin,Li et Wei)三种,其中以胰阔盘吸虫的分布区最大。关于本类吸虫的生物学问题近年来经国内外蠕虫学者的探讨而逐渐被了解(唐仲璋,1950;唐仲璋、唐崇惕,1975、1977;Basch,1965;Ksembaeva,1967;1973等)。国内在福建已详细观察了腔阔盘吸虫和枝睾阔盘吸虫生活史全过程,并经试验证实了它们的贝类宿主及不同的昆虫宿主的种类。胰阔盘吸虫的生活史虽亦经阐明,但     

窄口螺侧殖吸虫的发育史及早熟现象

1．本文描述从福州闽江泥滩采集的图氏窄口螺体中发现一新种侧殖吸虫,定名为窄口螺侧殖吸虫(Asymphylodora stenothyrae sp.nov．)并与其他相近虫种作详细比较。2．窄口螺侧殖吸虫的生活史各期发育经详细观察,本文简单介绍其各发育期形态特征。3．本文对窄口螺侧殖吸虫早熟现象及其他吸虫类的提早发育现象进行讨论,并将复殖吸虫亚纲曾经发现有提早发育现象的虫种及其中间宿主列表比较。我们的结论：早熟现象在吸虫类中是相当普遍的一种现象。     

窄口螺侧殖吸虫的发育史及早熟现象

1.本文描述从福州闽江泥滩采集的图氏窄口螺体中发现一新种侧殖吸虫,定名为窄口螺侧殖吸虫(Asymphylodora stenothyrae sp.nov.)并与其他相近虫种作详细比较。2.窄口螺侧殖吸虫的生活史各期发育经详细观察,本文简单介绍其各发育期形态特征。3.本文对窄口螺侧殖吸虫早熟现象及其他吸虫类的提早发育现象进行讨论,并将复殖吸虫亚纲曾经发现有提早发育现象的虫种及其中间宿主列表比较。我们的结论:早熟现象在吸虫类中是相当普遍的一种现象。       

福建北部山区耕牛枝睾阔盘吸虫的研究

枝睾阔盘吸虫(Eurytrema cladorchis Chin,Li et Wei,1965)也是寄生在牛羊等反刍动物胰管能严重引致病害的一种双腔类吸虫。目前尚只见报道于我国贵州、福建等地(金大雄等,1965)。关于它在国内外分布情况尚未了解,此虫种的生活史各期发育情况及其中间宿主种类都是以往科学上未经阐明的问题。我们于1976年得知,在我省北部浦城县九牧公社耕牛和羊只普遍感染枝睾阔盘吸虫,受害很严重。我们立即开展本项研究     

内蒙东部地区绵羊中华双腔吸虫生物学和流行病学的研究

中华双腔吸虫(Dicrocoelium chinensis Tang et Tang,1978)的生活史虽经研究,但本吸虫在第二中间宿主及终末宿主体内发育的情况尚未经阐明(唐崇惕等,1980).内蒙科右前旗附近数个旗县是本吸虫的流行区,1980—1981年我们在那里进行本项工作,从     

倪氏复口吸虫和湖北复口吸虫生活史的研究Ⅰ．早期幼虫的实验生态

本文比较研究了倪氏复口吸虫(Diplostomum niedashui pan＆Wang)和湖北复口吸虫(Diplostomum hupehensis pan＆Wang)早期生活史的实验生态,包括温度、光照度对它们直接和间接的影响及某些数量的变化。     

The egg bundles of the monogenean Dionchus remorae and their attachment to the gills of the remora, Echeneis naucrates

Gills of three remoras, Echeneis naucrates L., from Heron Island, Queensland, Australia had few adults but many attached egg bundles of the monogenean, Dionchus remorae. Studies of fresh, and preserved and cleared, primary gill lamellae bearing egg bundles and investigations with scanning electron microscopy and serial wax sections reveal proliferated host epithelium surrounding and embedding part of a loop of egg-shell material to which eggs are tethered, but eggs in each bundle hang free of gill tissue. This hyperplasia appears to anchor egg bundles to the host's gills. However, hyperplasia will take time to develop and cannot play a part in tethering newly laid egg bundles. Possible advantages to the parasite by attaching eggs to the gills of its host include improved oxygenation of the eggs, and a reduced risk of egg predation. Egg attachment by D. remorae to their remora hosts seems well adapted to successful larval invasion of fish which exhibit phoresy.     

Can host body size explain the parasite species richness in tropical freshwater fishes?

Summary The variability of monogenean gill ectoparasite species richness in 19 West African cyprinid species was analyzed using the following seven predictor variables: host size, number of drainage basins, number of sympatric cyprinid species, host diversity, association with mainland forest, host ecology, and monogenean biological labelling. The size of the host species accounted for 77% of the variation in the number of parasite species per host, and host ecology an additional 8%. Together the effects of host size and host ecology accounted for 85% of the variation in monogenean species richness. This study shows that the deciding factors for explaining monogenean species richness in West African cyprinid fishes are host species size and host ecology. These results were compared with main factors responsible for parasite species richness in fish communities. Other possible explanations of monogenean community structure in west African cyprinids are discussed.     

Colonization of Pacific islands by parasites of low dispersal ability: phylogeography of two monogenean species parasitizing butterflyfishes in the South Pacific Ocean

Aim To investigate the phylogeographical patterns of two poorly dispersing but widely distributed monogenean species, Haliotrema aurigae and Euryhaliotrematoides grandis, gill parasites of coral reef fishes from the family Chaetodontidae. Location South Pacific Ocean (SPO). Methods Sequence data from the mitochondrial cytochrome oxidase subunit I (COI) gene were obtained from samples from five localities of the SPO (Heron Island, Lizard Island, Moorea, Palau and Wallis) for the two parasite species. Phylogenetic and genetic diversity analyses were used to reconstruct phylogeographical patterns, and dates of cladogenetic events were estimated. Results Overall, 50 individuals of 17 Haliotrema aurigae and 33 of Euryhaliotrematoides grandis were sequenced from five localities of the SPO for COI mtDNA (798 bp). Our results revealed a deep phylogeographical structure in the species Euryhaliotrematoides grandis. The molecular divergence between individuals from Moorea and individuals from the remaining localities (7.7%) may be related to Pleistocene sea‐level fluctuations. In contrast, Haliotrema aurigae shows no phylogeographical patterns with the presence of most of the mitochondrial haplotypes in every locality sampled. Main conclusions Our study shows contrasting phylogeographical patterns of the two monogenean parasite species studied, despite many shared characteristics. Both parasites are found on the same host family, share the same geographical range and ecology, and are phylogenetically close. We propose two hypotheses that may help explain the diparity: the hypotheses involve differences in the evolutionary age of the parasite species and their dispersal capabilities. Additionally, the lack of phylogeographical structure in Haliotrema aurigae contrasts with its apparently restricted dispersion, which is likely to occur during the egg stage of the life cycle, inducing a passive dispersal mechanism in butterflyfish monogeneans.     

A nested parasite species subset pattern in tropical fish: host as major determinant of parasite infracommunity structure

The number of monogenean gill parasite species associated with fish hosts of different sizes is evaluated for 35 host individuals of the West African cyprinid Labeo coubie. The length of host individuals explains 86% of the total variation in monogenean species richness among individuals. Larger hosts harbour more species than smaller ones. The existence of a hierarchical association of parasite species in individuals of L. coubie is demonstrated. Monogenean infracommunities on larger fish hosts consist of all species found on smaller hosts plus those restricted to the larger size categories, suggesting some degree of compositional persistence among host individuals. The findings provide strong support for an interpretation of the relationship between monogenean parasite species richness and host body size in terms of a nested species subset pattern, thus providing a new record of repetitive structure and predictability for parasite infracommunities of hosts.After 15/01/1995, ORSTOM, BP 165 97323 Cayenne cedex Guyane France     

Parasite fauna of introduced pumpkinseed fish Lepomis gibbosus: first British record of Onchocleidus dispar (Monogenea)

A survey of pumpkinseed Lepomis gibbosus from a stillwater fishery in southern England revealed infections by the ancyrocephalid monogenean Onchocleidus dispar at 100% prevalence. Host specificity of O. dispar to North American centrarchid fish suggests that it is a non-native parasite, introduced to Britain with L. gibbosus. Mean intensity of O. dispar was significantly higher in male (25.5 parasites) compared to female (15) and immature (7) hosts, but was not influenced by host standard length or sampling time. This sex-biased parasitism is likely to be related to both ecological and physiological factors, such as differential exposure to infective stages during nest building, or higher susceptibility to infection due to enhanced host stress levels. O. dispar significantly dominated the external surfaces and the outer gill arches. Analysis of the spatial distribution of the parasite between the 9 regions of gill surface determined that as density increased, higher numbers of parasites were found on the anterior and central gill regions compared to posterior (distal) regions. Apparent microhabitat selection is discussed in terms O. dispar life cycle, maximising oxygen availability, avoiding unstable areas and increasing intraspecific contact. The absence of O. dispar in the gills of roach, rudd and gudgeon sampled from the same fishery supports the assumption that this parasite is currently of little threat to native fish populations.     

The niche of Salsuginus thalkeni, a gill parasite of Fundulus zebrinus

Distribution of a monogenean parasitic helminth Salsuginus thalkeni on the gills of the fish Fundulus zebrinus is described by calculation of mean positions and niche breadths on the linear spatial resource gradients gill filament length, gill arch length and arch number. All distributions are given for parasites in the presence and absence of various combinations of potential competitors, namely the 6 other parasite species that occupy the same host species. Filament niche breadth was narrowest in the absence of potential competitors; breadth on arch was widest in the presence of potential competitors. Breadth on both resources was correlated positively with mean number of parasites per individual. Arch breadth exhibited cyclic seasonal changes, being lowest in early to mid-summer. Mean position exhibited no repeated pattern of variation on either resource. The results are considered consistent with predictions about the niche structures of species in unsaturated noninteractive specialist communities.     

How to evade a coevolving brood parasite: egg discrimination versus egg variability as host defences

Arms races between avian brood parasites and their hosts often result in parasitic mimicry of host eggs, to evade rejection. Once egg mimicry has evolved, host defences could escalate in two ways: (i) hosts could improve their level of egg discrimination; and (ii) negative frequency-dependent selection could generate increased variation in egg appearance (polymorphism) among individuals. Proficiency in one defence might reduce selection on the other, while a combination of the two should enable successful rejection of parasitic eggs. We compared three highly variable host species of the Afrotropical cuckoo finch Anomalospiza imberbis, using egg rejection experiments and modelling of avian colour and pattern vision. We show that each differed in their level of polymorphism, in the visual cues they used to reject foreign eggs, and in their degree of discrimination. The most polymorphic host had the crudest discrimination, whereas the least polymorphic was most discriminating. The third species, not currently parasitized, was intermediate for both defences. A model simulating parasitic laying and host rejection behaviour based on the field experiments showed that the two host strategies result in approximately the same fitness advantage to hosts. Thus, neither strategy is superior, but rather they reflect alternative potential evolutionary trajectories.     

The microhabitat distribution of two Dactylogyrus species parasitizing the gills of the barbel, Barbus barbus

The microhabitat distribution of two congeneric species Dactylogyrus carpathicus and D. malleus (Monogenea) parasitizing the gills of the barbel (Barbus barbus L.) was investigated. We tested whether congeneric species exhibited microhabitat preference and whether interspecific interactions could be attributed to the microhabitat segregation of congeners. The outlying mean index method was used to evaluate species microhabitats. Gill variables (different microhabitats within gills) were used as environmental factors characterizing the gills. When abundances of both species were highest, and no significant difference was found between the abundance of the two species, the gill segments and gill areas were the most important factors segregating the Dactylogyrus species on the gills. Niche overlap was low within each of the four gill arches, and parasites were segregated in the same microhabitats within each gill arch. When abundances of both species were low, each monogenean species was segregated at the level of the gill arches. When abundances of both species increased, the niche and overlap between species increased. The distribution of both congeneric species confirmed microhabitat preference within the gills. The results suggest that microhabitat preference is dependent on species abundances, species being segregated in the case of low abundance, possibly to increasing mating opportunities. Both niche and overlap between species increased with species abundance. In the case of the high abundance of both species, microhabitat preference seems to be related to interspecific interactions between monogenean species, as previously found for endoparasitic species.     

The "third eye"-- a new concept of trans-differentiation of pineal gland into median eye in amphibian tadpoles of Bufo melanostictus

Median third eye was found to develop from transplanted pineal gland of external gill stage tadpoles in the recipient 5 toe stage tadpoles of Bufo melanostictus. Pineal gland along with a bit part of brain tissue of the donor external gill stage tadpole was cut out and transplanted into a pit made between two lateral eyes of 5 toe stage recipient tadpoles. Half of the operated tadpoles were treated with vitamin A (15 IU/ml.) for 15 days. Median "third eye" was found to develop in the both untreated and vitamin A treated tadpoles. However, vitamin A increased the percentage of the development of median eyes. Morphological and histological study revealed that newly transformed median eyes were similar to that of normal functional eyes. A stalk like structure developed which connects the median eye to the brain. The median third eye could not develop when pineal gland of 5 toe stage mature tadpole was transplanted into the tadpole of the same age.     

Population dynamics of Philureter trigoniopsis (Monogenea: Ancyrocephalinae) from urinary organs of Galaxias maculatus (Osmeriformes: Galaxiidae) in a cold temperate Andean Patagonian lake (Argentina)

Philureter trigoniopsis parasitizes the ureters and urinary bladder of Galaxias maculatus in Patagonian Andean lakes. To investigate factors associated with variation in the prevalence and intensity of this monogenean, fish were sampled periodically over 2 yr in Lake Gutiérrez. Prevalence and mean intensity are higher in smaller fishes than in larger ones. A seasonal pattern was observed, with peak recruitment and peak mean intensity occurring in early spring (September), followed by lows in late summer (January-February). Galaxias maculatus length classes are spatially segregated due to seasonal migrations, so the annual infection cycle is characterized by higher prevalence and intensity from late winter to early summer in the smaller fish from the deep zone of the lake.