Further Observations on Tylenchinema oscinellœ Goodey, 1930, a Nematode Parasite of the Frit-fly

1931 ◽  
Vol 9 (3) ◽  
pp. 157-174 ◽  
Author(s):  
T. Goodey
Keyword(s):  
Life History ◽  
Living Condition ◽  
Nematode Parasite ◽  
Free Living ◽  
Male And Female ◽  
Winter Cereals ◽  
Two Generations ◽  
Fly Larvae ◽  
Complete Account

In the original paper dealing with this interesting nematode a fairly complete account was given of its discovery, its life-history in the free-living condition and within the host. In addition, its effect on the host, whereby flies of both sexes are sterilised owing to its presence, was also described. Its occurrence in both the stem and panicle generations of frit-flies attacking oats was recorded and figures were presented showing the incidence of infection in flies of these two generations. At the same time the inference was drawn that the parasite must also occur in the over-wintering generation of the frit-fly, larvæ of which attack wild grasses or winter cereals. Observations were therefore necessary on flies of this generation emerging during 1930 to prove conclusively the presence of the parasite. These observations are dealt with in the present paper and figures are given showing the degree of infestation in both male and female flies.

On the Morphology and Life History of Aproctonema entomophagum Keilin, a Nematode Parasite in the Larvae of Sciara pullula Winn. (Diptera—Nematocera)

Parasitology ◽  
1933 ◽  
Vol 25 (3) ◽  
pp. 285-295 ◽  
Author(s):  
D. Keilin ◽  
V. C. Robinson
Keyword(s):  
Life History ◽  
Systematic Position ◽  
Egg Laying ◽  
Nematode Parasite ◽  
Free Living ◽  
The Family ◽  
Two Generations ◽  
History Of ◽  
Decaying Wood

1. An account is given of Aproctonema entomophagum Keilin 1917, a Nematode parasite of the larvae of a Mycetophilid fly, Sciara pullula Winn., inhabiting decaying wood.2. The life history of this parasite is remarkable in the following respects:(a) The free-living stage is very short.(b) Both sexes are parasitic.(c) The usual host is the larva of the fly, from which the parasite escapes by actively breaking through the skin; but some parasites may be carried through to the imagines, from which they escape largely by the aid of the egg-laying movements provoked by them in the flies.3. Metamorphosis of the Sciara larva is delayed by the parasitism, so that at least two generations of Nematodes may be found in one host.4. All the parasitised imagines so far examined have been females.5. The systematic position of Aproctonema is discussed, the conclusion being that this worm and its near relative, Tetradonema plicans Cobb 1919, represent two closely allied genera of the family Mermithidae, but are not synonymous with Mermis. It is proposed to dispense with the family Tetra-donematidae Cobb.

On the Nematode Parasite of the frit-fly, Oscinella frit, L

1930 ◽  
Vol 8 (3) ◽  
pp. 123-132 ◽  
Author(s):  
T. Goodey
Keyword(s):  
Life History ◽  
Royal Society ◽  
Reproductive Organs ◽  
Body Cavity ◽  
The Body ◽  
Nematode Parasite ◽  
Plant Tissues ◽  
Present Communication ◽  
Large Numbers ◽  
Fly Larvae

In a paper recently published in the Philosophical Transactions of the Royal Society of London, the writer describes the discovery of certain small Tylenchoid nematodes in the swollen stems of the seedling oats suffering from frit-fly attack at Winches Farm, St. Albans. Adults of both sexes and larvæ undergoing the last two moults were found in the destroyed plant tissues surrounding the fly larvæ. The spermatized female worms were next discovered within the body-cavity of the frit-fly larvæ. In due course, they were obtained from pupæ of the fly, having increased in size, and finally were found within adult flies of both sexes lying coiled within the abdomen as comparatively large sausage-shaped worms. As a result of the presence of the worm, the flies are sterilised, being unable to develop their reproductive organs. The worms become viviparous and shed large numbers of larvæ into the body-cavity of the fly and these, after undergoing a certain amount of growth, make their way into the gut of the host and pass to the exterior via the anus. In the present communication a brief account is given of the principal observations on the new parasite, its life-history and the effects on the host, described in detail in the original paper.

Reproduction in Strongyloides (Nematoda): a life between sex and parthenogenesis

Parasitology ◽  
2007 ◽  
Vol 135 (3) ◽  
pp. 285-294 ◽  
Author(s):  
A. STREIT
Keyword(s):  
Life Cycle ◽  
Present Article ◽  
Free Living ◽  
Male And Female ◽  
Genomic Tools ◽  
Two Generations ◽  
Small Intestines ◽  
Parasitic Life Cycle ◽  
Key Questions

SUMMARYNematodes of the genus Strongyloides parasitize the small intestines of vertebrates. In addition to a parasitic life-cycle, which is generally considered to be parthenogenetic, Strongyloides can also have a facultative, free-living generation involving male and female worms. The purpose of the present article was to review the literature on the modes of reproduction, the routes of development in the two generations of Strongyloides, discuss the controversial opinions in the literature regarding these aspects and point to new opportunities for addressing key questions in relation to the biology of reproduction of members of the genus employing genetic and genomic tools.

Parastrongyloides winchesi gen. et sp. nov. A Remarkable New Nematode Parasite of the Mole and the Shrew

1928 ◽  
Vol 6 (2) ◽  
pp. 79-86 ◽  
Author(s):  
D. O. Morgan
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Nematode Parasite ◽  
Infective Stage ◽  
Parasitic Stage ◽  
Free Living ◽  
Nematode Genus ◽  
Males And Females ◽  
Chief Interest

The species of the Nematode genus Strongyloides are of considerable interest to helminthologists and extensive studies on the biology of their life-history have been carried out by various workers. Their chief interest lies in the fact that the parasitic stage consists of hermaphroditic forms only, while in the free-living stage there may be a differentiation into males and females before reaching the infective stage. This alternation in the life-cycle is also exhibited by the allied genus Rhabdias, with the exception that, according to Railliet (1899) and Goodey (1922), certain species from the snake do not appear to have this differentiation in the free-living stage.

scholarly journals On the lack of adaptation in the Tristichaceœ and Podostemaceœ

1914 ◽  
Vol 87 (598) ◽  
pp. 532-550 ◽  
Keyword(s):  
Life History ◽  
Morphological Structure ◽  
Living Condition ◽  
Flowering Plants ◽  
Natural Habitats ◽  
Dead Material ◽  
Dry Seasons ◽  
Great Uniformity ◽  
High Degree

With the exception of some of the parasitic orders, such as the Balanophoraceœ , there are probably no families of flowering plants—one might almost include flowerless—which are so completely transformed from the average or mesophytic type of the phanerogams into types which are so completely unique and peculiar, as the Tristichaceæ and still more the Podostemaceæ. Nor are there any in which, with such very great uniformity in the conditions of life, there is such remarkable variety in the morphological structure. The structure of the orders, or rather of their members, being unique, and the conditions under which they live being also unique, it has been taken for granted that the former is in a high degree adapted to the latter, the flat thallus-like expansions of stem or root being looked upon as admirably suited to the rushing water in which they live. So long as we were almost completely ignorant of the actual living plants, and content with dead material collected mainly in the dry seasons, this was all very well, but now that for 17 years I have devoted much attention to these plants,* have studied them in the living condition in their natural habitats in India, Ceylon, and Brazil, have followed them from germination right through their life-history, and in other ways become absolutely familiar with them, and as a result of all this have arrived at diametrically opposite conclusions, it will repay us to examine into the question in some detail.

On Crepidostomum farionis O. F. Müll. (= Stephanophiala laureata Zeder), a Distome Parasite of the Trout and Grayling. I. The Life History

Parasitology ◽  
1927 ◽  
Vol 19 (1) ◽  
pp. 86-99 ◽  
Author(s):  
F. J. Brown
Keyword(s):  
Life History ◽  
Gall Bladder ◽  
Excretory Vesicle ◽  
Intermediate Hosts ◽  
Larval Trematode ◽  
Sphaerium Corneum ◽  
Two Generations ◽  
History Of ◽  
Second Intermediate Host ◽  
Ephemera Danica

1. Crepidostomum farionis inhabits the gall bladder, as well as the intestine and pyloric caeca, of the trout and grayling.2. The life history of Crepidostomum farionis has been worked out and is based on the similarity of organisation of the cercaria, encysted larval trematode and the adult.3. The first intermediate hosts in the life history of this trematode are Pisidium amnicum (Müll.) and Sphaerium corneum (L.) though the latter is unusual.4. The second intermediate host is the larva of the mayfly, Ephemera danica (Müll.).5. There are two generations of rediae, the first gives rise to daughter rediae, which in turn produce cercariae.6. The rediae are characterised by the absence of ambulatory processes and a functional intestine.7. The cercaria (n.sp.) possesses “eye spots,” stylet and gland cells (salivary?), and the excretory vesicle is tube-shaped.8. The excretory system of the redia and the cercaria has been worked out in detail.9. The relation of the parasites to their respective hosts is discussed. On account of the need for further observations definite conclusions are held over for a later paper.

scholarly journals On Apogamy and the development of Sporangia upon fern prothalli

1898 ◽  
Vol 63 (389-400) ◽  
pp. 56-61
Keyword(s):  
Life History ◽  
Point Of View ◽  
The Other ◽  
Normal Life ◽  
Other Hand ◽  
General Importance ◽  
Two Generations ◽  
History Of ◽  
Alternation Of Generations

The two most important deviations from the normal life-history of ferns, apogamy and apospory, are of interest in themselves, but acquire a more general importance from the possibility that their study may throw light on the nature of alternation of generations in archegoniate plants. They have been considered from this point of view Pringsheim, and by those who, following him, regard the two generations as homologous with one another in the sense that the sporophyte arose by the gradual modification of individuals originally resemblin the sexual plant. Celakovsky and Bower, on the other hand, maintaint the view tha t the sporophyte, as an interpolated stage in the life-history arising by elaboration of the zygote, a few thallophytes.

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