The Genus Proteocephalus in the Netherlands

1969 ◽  
Vol 43 (1-2) ◽  
pp. 207-222 ◽  
Author(s):  
J. J. Willemse
Keyword(s):  
The Netherlands ◽  
Intermediate Host ◽  
Host Specificity ◽  
Host Species ◽  
Perca Fluviatilis ◽  
Anguilla Anguilla ◽  
Intestinal Wall ◽  
Original Host ◽  
Osmerus Eperlanus ◽  
High Degree

The present paper deals with investigations on the occurrence in Netherlands' fresh water fishes and host specificity of tapeworms belonging to the genus Proteocephalus. The species involved are:P. tetrastomus (Rudoiphi, 1810) in smelt, Osmerus eperlanus.P. longicollis (Zeder, 1800) in smelt, Osmerus eperlanus.P. cernuae (Gmelin, 1790) in pope, Acerina cernua.P. ocellatus (Rudolphi, 1802) in perch, Perca fluviatilis.P. macrocephalus (Creplin, 1825) in eel, Anguilla anguilla.Seasonal cycles were found in P. telrastomus and P. ocellalus; in the latter species this was certainly induced by low winter temperatures.Experimental infections showed that a high degree of host specificity exists in all species considered. Infections of an alien host were never successful. Two kinds of infections were carried out: (a) feeding plerocercoids (in the intermediate host), coming from a known source, to a number of fishes, belonging to several species including the original host species, and (b) transplanting worms, collected from the intestine of a fish, to the intestines of a number of other fishes, belonging to several species including the original host species.Notwithstanding the high degree of host specificity, worms may survive for one or two days, but usually in a bad condition, in the intestine of an alien host. Occasionally they survived up to 14 days: e.g. P. tetratomus in Anguilla anguilla. Consequently sometimes dissections of predator fishes or carrion eating fishes may produce dubious host records because actually Proteocephalus from their prey are recorded. We are convinced that P. tetrastomus found in Salmo trutta, Platichihys flesus and Perca fluviatilis originate from Osmerus eperlanus having been eaten by these species.Additionally cannibalism may be responsible for the fact that large specimens of some fish species, e.g. smelt, are heavily infected with Proteocephalus while they hardly eat any Cyclops, the intermediate host. This is clearly demonstrated by the transplantation experiments, transplanting worms to the proper host.From the data recorded it is apparent that representatives of the genus Proteocephalus are not harmful to commercially important fishes in the Netherlands. In these fishes natural infection with the proper species of Proteocephalus is low and successful infection with other species, showing a high incidence in less valuable fishes, is prevented by the high degree of host specificity. Additionally worms of the species studied did not injure the tissues of the intestinal wall by the action of their suckers and piercing of the intestinal wall never occurred. Even smelts infected with large numbers of worms-more than 50 in a single 20 cm. specimen-did not show any abnormalities in genital development or in the amount of fat in the body cavity.

The Influence of Various Definitive Hosts on the Development ofDiplostomum phoxini(Strigeida, Trematoda)

1960 ◽  
Vol 34 (3-4) ◽  
pp. 205-210 ◽  
Author(s):  
A. D. Berrie
Keyword(s):  
Intermediate Host ◽  
Host Specificity ◽  
Host Species ◽  
Freshwater Snail ◽  
Herring Gull ◽  
Lymnaea Peregra ◽  
First Intermediate Host

.1. Infection withDiplostomulum phoxiniis very common among minnows in the Glasgow area of Scotland.2. The first intermediate host of the parasite in this area is shown to be the freshwater snailLymnaea peregra.3. Adult flukes were obtained experimentally in mice, ducklings and herring-gull chicks.4. Significant differences are shown to occur between adult flukes recovered from different host species.5. The implications of these findings in relation to the host specificity and the classification of the Strigeida are briefly discussed.

The life-cycle of Bucephaloides gracilescens (Rudolphi, 1819) Hopkins, 1954 (Digenea: Gasterostomata)

Parasitology ◽  
1974 ◽  
Vol 68 (1) ◽  
pp. 1-12 ◽  
Author(s):  
R. A. Matthews
Keyword(s):  
Life Cycle ◽  
Intermediate Host ◽  
Host Specificity ◽  
Comparative Morphology ◽  
Rock Pools ◽  
Second Intermediate Host ◽  
High Degree ◽  
First Time ◽  
First Intermediate Host

The cercaria and sporocyst of Bucephaloides gracilescens are described from Abra alba (Wood). Observations were made on the behaviour of the cercaria and the mechanism of release from the first intermediate host. The metacercaria was obtained experimentally for the first time using Ciliata mustela (L.), a species of Gadidae from rock pools, as second intermediate host. It has not previously been recorded from this fish. Unsuccessful attempts were made to infect species of fishes from three other families, namely, Bothidae, Pleuronectidae and Gobiidae, confirming the high degree of host specificity of the metacercaria to Gadidae. The metacercaria, its development and effect on the host are briefly discussed. It was linked with the adult on the basis of comparative morphology and ecology of the hosts.

scholarly journals THE RELATIONSHIP BETWEEN THE FUSARIUM YELLOWS DISEASES OF SUGAR BEET AND SPINACH.

HortScience ◽  
1991 ◽  
Vol 26 (5) ◽  
pp. 488d-488
Author(s):  
Ray D. Martyn ◽  
C. M. Rush ◽  
E. A. Dillard ◽  
D. H. Kim
Keyword(s):  
Sugar Beet ◽  
Host Specificity ◽  
Genetic Similarity ◽  
Rflp Markers ◽  
Original Host ◽  
Pathogenicity Tests ◽  
High Degree ◽  
The Relationship ◽  
Mtdna Rflp ◽  
Yellows Diseases

Twenty isolates of Fusarium oxysporum recovered from diseased sugar beet and spinach (Chenopodiaceae) or red-root pigweed (Amaranthaceae) were examined using pathogenicity, isozyme, and mtDNA RFLP markers to determine genetic similarity among isolates from different hosts. Pathogenicity tests defined several levels of host specificity. Most isolates were specific to their original host; however, a few primarily were pathogenic to their original host but also caused some wilt on other hosts. Two isolates were pathogenic on all three hosts and six were not pathogenic to any of the hosts. Differences in isozymes and mtDNA RFLPs corresponded with differences in pathogenicity. Three main polymorphic groups based on host specificity were identified along with three sub-groups corresponding to aggressiveness of the isolates. These data suggest that while most isolates display a high degree of host specificity isolates exist within the population that lack such specificity and cross over to other species.

Introduction

2017 ◽  
Author(s):  
Detlef Pollack ◽  
Gergely Rosta
Keyword(s):  
The Netherlands ◽  
Western Europe ◽  
West Germany ◽  
World Today ◽  
The World ◽  
Degree Of Stability ◽  
Important Exception ◽  
High Degree ◽  
Religious Landscape

In recantation of his earlier approach, Peter L. Berger now claims: ‘The world today, with some exceptions […], is as furiously religious as it ever was, and in some places more so than ever.’ The most important exception that Berger refers to is Western Europe. The introduction to Part II provides an overview of the religious landscape in Western Europe. The data show that the current religious situation in the countries of Western Europe is in fact subject to considerable variation. It would therefore be erroneous to describe Western Europe as secularized. At the same time, the data reveal that there have been clear secularization tendencies over the last few decades. To grasp the diversity of religious tendencies, Part II deals with three cases: West Germany with moderate downward tendencies, Italy with a considerably high degree of stability, and the Netherlands displaying disproportionately strong secularizing tendencies.

scholarly journals Co-extinct and critically co-endangered species of parasitic lice, and conservation-induced extinction: should lice be reintroduced to their hosts?

Oryx ◽  
2014 ◽  
Vol 49 (1) ◽  
pp. 107-110 ◽  
Author(s):  
Lajos Rózsa ◽  
Zoltán Vas
Keyword(s):  
Endangered Species ◽  
Host Specificity ◽  
Host Species ◽  
Conservation Status ◽  
Iucn Red List ◽  
Red List ◽  
Published Data ◽  
Common Phenomenon ◽  
Global Extinction

AbstractThe co-extinction of parasitic taxa and their host species is considered a common phenomenon in the current global extinction crisis. However, information about the conservation status of parasitic taxa is scarce. We present a global list of co-extinct and critically co-endangered parasitic lice (Phthiraptera), based on published data on their host-specificity and their hosts’ conservation status according to the IUCN Red List. We list six co-extinct and 40 (possibly 41) critically co-endangered species. Additionally, we recognize 2–4 species that went extinct as a result of conservation efforts to save their hosts. Conservationists should consider preserving host-specific lice as part of their efforts to save species.

Host specificity in the host-seeking larva of the dipteran parasitoidMallophora ruficaudaand the influence of age on parasitism decisions

2014 ◽  
Vol 104 (3) ◽  
pp. 295-306 ◽  
Author(s):  
M.E. Barrantes ◽  
M.K. Castelo
Keyword(s):  
Host Specificity ◽  
Host Species ◽  
Instar Larva ◽  
Distribution Area ◽  
Host Acceptance ◽  
Chemical Stimulus ◽  
Chemical Cue ◽  
Behavioural Flexibility ◽  
White Grubs ◽  
Host Seeking

AbstractLarvae of the robber flyMallophora ruficaudaare ectoparasitoids of white grubs and adults are an important apiculture pest in Argentina. Females oviposit on tall grasses and the second instar larva actively searches and locates hosts. There are nine potential hosts in the distribution area of this parasitoid andCyclocephala signaticollis(Coleoptera: Scarabaeidae) is the most parasitized in the field. However,M. ruficaudahas a certain degree of behavioural flexibility towards different host species, and not being a strict specialist. The conditions under which the parasitoid orientates and accepts different hosts’ species are unknown. We studied the host specificity ofM. ruficaudatowards three species ofCyclocephalagenus and we determined whether this specificity depends on larval age. We also evaluated whether larva orientation towardsCyclocephalaspecies changes with chemical cue concentration. We assessed host specificity measuring the orientation and acceptance behaviours towards kairomones extracts and live individuals ofCyclocephalaspecies usingM. ruficaudalarvae of low and high life expectancy (i.e., young and aged second instar larvae). We observed that young larvae orientated only towardsC. signaticollischemical stimulus, whereas aged larvae orientated also towardsC. modesta, and the same was observed with increasing stimuli's concentration. Both young and agedM. ruficaudalarvae orientate towards liveC. signaticollisandC. putridaspecies and rejectedC. modesta. Also, we found that larvae accepted allCyclocephalahosts. In conclusion, our results indicate that specificity in the laboratory, observed through host orientation and host acceptance behaviours, depends not only on the availability of host species, but also on the nature of the host's stimuli combined with parasitoid age.

The influence of second intermediate host species on the infectivity of metacercarial cysts of Echinoparyphium recurvatum

1999 ◽  
Vol 73 (2) ◽  
pp. 143-145 ◽  
Author(s):  
A.M. McCarthy
Keyword(s):  
Intermediate Host ◽  
Definitive Host ◽  
Host Species ◽  
Post Infection ◽  
Rana Temporaria ◽  
Biomphalaria Glabrata ◽  
Reproductive Status ◽  
Intermediate Hosts ◽  
Potential Influence ◽  
Second Intermediate Host

The potential influence of second intermediate host species on the infectivity of metacercarial cysts of Echinoparyphium recurvatum to the definitive host Anas platyrhynchos was examined experimentally. Echinoparyphium recurvatum metacercarial cysts were obtained from the following experimentally infected second intermediate hosts 14 days post expsoure to cercariae: Lymnaea peregra; Physa fontinalis; L. stagnalis;Planorbis planorbis; Biomphalaria glabrata; tadpoles of the amphibian Rana temporaria. Metacercarial cysts from each of these hosts were fed, in doses of 50 cysts per individual, to separate groups composed of between four and eight, 3-day-old A. platyrhynchos ducklings. All A. platyrhynchos were necropsied 15 days post-infection and the number, size, and reproductive status of E. recurvatum worms in the intestine was recorded. Analyses of variance on the number (transformed log (x + 1)) and size of worms revealed no significant differences in worms originating from metacercariae formed in the different second intermediate hosts (worm number P > 0.05, and worm size P > 0.05). All worms recovered were found to be gravid. It is therefore concluded that the species of second intermediate host utilized does not influence the infectivity of the metacercarial cyst of E. recurvatum, nor the subsequent establishment and reproductive status of the parasite in A. platyrhynchos.

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