Observations on the Life History of Triodontophorus tenuicollis, a Nematode Parasite of the Horse

1925 ◽  
Vol 3 (1) ◽  
pp. 1-14 ◽  
Author(s):  
R. J. Ortlepp
Keyword(s):  
Buccal Capsule ◽  
Stage Larva ◽  
Fourth Stage ◽  
Free Living ◽  
Larval Stages ◽  
Third Stage ◽  
History Of ◽  
Last Stage ◽  
Marked Resistance ◽  
Fourth Stage Larva

1. During the free-living development the larvæ of Triodontophorus tenuicollis undergo two moults separating three larval stages, the last stage remaining ensheathed in the cuticule of the previous stage.2. The development takes about four days when the eggs are cultured in horse fæces and charcoal at 26° C.3. The infective or third stage larvæ are climbers, and also show a marked resistance to desiccation ; they can also withstand variations in temperature from – 8° C. to 60° C.4. They do not penetrate skin.5. Infection of the host is probably via the mouth during grazing.6. The fourth-stage larva is described. It is free in the lumen of the colon, possesses a well-marked larval buccal capsule and three stout and pointed œsophageal teeth. Sex differences are now present.7. The adult buccal capsule develops in the form of a vesicle round the base of the larval buccal capsule.8. The probable mode of its parasitic development is given.9. A fourth-stage larva, probably that of either T. brevicauda or T. serratus, is described.

Studies on the life-history of Bunostomum phlebotomum (Railliet, 1900), a hookworm parasite of cattle

Parasitology ◽  
1946 ◽  
Vol 37 (3-4) ◽  
pp. 192-201 ◽  
Author(s):  
J. F. A. Sprent
Keyword(s):  
Infective Larva ◽  
Stage Larva ◽  
Fourth Stage ◽  
Larval Stages ◽  
The Third ◽  
Third Stage ◽  
History Of ◽  
Time Required ◽  
Cutaneous Blood ◽  
Fourth Stage Larva

A description is given of the processes of copulation, formation of the egg and spermatozoon, cleavage, embryogeny and hatching in B. phlebotomum. These processes were found to be essentially similar to those in other strongyle nematodes.The anatomy of the first three larval stages is described and the observations of Conradi & Barnette (1908) and Schwartz (1924) were largely confirmed.Penetration of the skin of calves by the infective larva was observed histologically. The larvae were found to have reached the dermis within 30 min. and to have penetrated the cutaneous blood vessels within 60 min. of application to the skin. The larvae were found in the lung where the third ecdysis was in progress 10 days after penetration of the skin. A description is given of the growth of the third-stage larva in the lung, the changes which take place during the third ecdysis, and the anatomy of the fourth-stage larva.The fourth-stage larvae exsheath in the lungs and travel to the intestine. After a period of growth in which sexual differentiation takes place, the fourth ecdysis occurs and the adult parasite emerges. The time required for the attainment of maturity was found to be somewhere between 30 and 56 days after penetration of the skin.This paper was written at the Ministry of Agriculture and Fisheries Veterinary Laboratories, Wey-bridge, and the writer would like to express his gratitude to the Director, Prof. T. Dalling, also to Dr W. R. Wooldridge, chairman of the Council of the Veterinary Educational Trust for their help and encouragement. The writer's thanks are also due to Dr H. A. Baylis, Prof. R. T. Leiper and Dr E. L. Taylor for their advice and help on technical points, and to Mr R. A. O. Shonekan, African laboratory assistant, for his able co-operation.

Some Stages in the Development of Œsophagostomum dentatum from the Pig

1926 ◽  
Vol 4 (4-5) ◽  
pp. 191-198 ◽  
Author(s):  
T. Goodey
Keyword(s):  
Life History ◽  
Buccal Capsule ◽  
Stage Larva ◽  
Infective Stage ◽  
Free Living ◽  
Larval Stages ◽  
Oesophagostomum Dentatum ◽  
General Plan ◽  
History Of

In an earlier paper (Goodey, 1924), the writer has given an account of the morphology of the adults of Œsophagostomum dentatum, the development and structure of the free-living larvæ and the biology of the ensheathed infective stage. So far, however, the parasitic larval stages have not been described. In the present paper some of the gaps in our knowledge of the complete life-history of the worm represented by these stages are filled in, not as completely as could be desired owing to the absence from the material of specimens showing the 3rd and 4th ecdyses. The worms found, however, show that the 4th stage larva has a provisional buccal capsule essentially similar to that found in 4th stage larvæ of O. radiatum (Marotel, 1908) and O. columbianum (Veglia, 1924), and in this respect is in line with certain other 4th stage larvæ of the Strongyloidea such as Ancylosloma duodenale (Looss, 1897), and Triodontophorus tenuicollis (Ortlepp, 1925), in which provisional buccal capsules built on the same general plan have been observed.

The life history of Hysterothylacium analarum Rye and Baker, 1984 (Nematoda: Anisakidae) in Lepomis gibbosus (Pisces: Centrarchidae) in southern Ontario, Canada

1992 ◽  
Vol 70 (8) ◽  
pp. 1576-1584
Author(s):  
Leslie A. Rye ◽  
Michael R. Baker
Keyword(s):  
Seasonal Pattern ◽  
Late Summer ◽  
Intestinal Lumen ◽  
Lepomis Gibbosus ◽  
Fourth Stage ◽  
Larval Stages ◽  
Second Stage ◽  
Third Stage ◽  
History Of ◽  
Gravid Females

Larval stages of Hysterothylacium analarum are described from Lepomis gibbosus in Dawson Pond, Ontario (45°10′N, 78°50′W). Second-stage larvae were easily distinguished from all other stages by the presence of a conical boring tooth. Third-stage larvae lacked both a boring tooth and lips. Fourth-stage larvae had well-developed lips. The ratio of ventricular appendage length to intestinal caecum length varied greatly between larval stages and adults. Prevalence and intensity of larval stages and adult H. analarum showed a distinct seasonal pattern, with one generation of adult worms per year. In spring, third-stage larvae left nodules on the intestinal serosa of L. gibbosus and migrated to the intestinal lumen, where they rapidly moulted to the fourth-stage and then to adult worms. Eggs collected from gravid females developed to second stage larvae in approximately 5 days under laboratory conditions. In natural infections in the late summer second-stage larvae were found in nodules on the serosa and in the mesentery. Larvae apparently moulted to the third stage and overwintered in the nodules as third-stage larvae.

Morphological description of the pupa and redescription of the adults and larva of Culex (Culex) apicinus Philippi (Diptera: Culicidae)

Zootaxa ◽  
2008 ◽  
Vol 1941 (1) ◽  
pp. 31-42 ◽  
Author(s):  
GUSTAVO CARLOS ROSSI ◽  
MAGDALENA LAURITO ◽  
WALTER RICARDO ALMIRÓN
Keyword(s):  
Species Distribution ◽  
Male Genitalia ◽  
Stage Larva ◽  
Morphological Description ◽  
Fourth Stage ◽  
Available Information ◽  
First Time ◽  
Fourth Stage Larva

The adult, fourth-stage larvae and the male genitalia of Culex (Culex) apicinus Philippi is redescribed. The pupa is described for the first time. The male genitalia, pupa and fourth-stage larva are illustrated. The available information on the taxonomy and distribution of the species is also included, extending the species distribution in Argentina. Bionomics and distributional data are provided for Culex apicinus.

The life cycle of Paraquimperia tenerrima: a parasite of the European eel Anguilla anguilla

2005 ◽  
Vol 79 (2) ◽  
pp. 169-176 ◽  
Author(s):  
J.A. Shears ◽  
C.R. Kennedy
Keyword(s):  
Life Cycle ◽  
Intermediate Host ◽  
Anguilla Anguilla ◽  
European Eel ◽  
Temperature Dependent ◽  
Free Living ◽  
Freshwater Invertebrate ◽  
Third Stage ◽  
History Of ◽  
Whole Life Cycle

AbstractPrevious studies on the life history of the nematode eel specialist Paraquimperia tenerrima (Nematoda: Quimperiidae) have failed to determine whether an intermediate host is required in the life cycle. In the laboratory, eggs failed to hatch below 10°C, hatching occurring only at temperatures between 11 and 30°C. Survival of the free-living second stage larvae (L2) was also temperature dependent, with maximal survival between 10 and 20°C. Total survival of the free-living stages (eggs and L2) is unlikely to exceed a month at normal summer water temperatures, confirming that parasite could not survive the 6 month gap between shedding of eggs in spring and infection of eels in early winter outside of a host. Eels could not be infected directly with L2, nor could a range of common freshwater invertebrate species. Third stage larvae (L3) resembling P. tenerrima were found frequently and abundantly in the swimbladder of minnows Phoxinus phoxinus from several localities throughout the year and were able to survive in this host in the laboratory for at least 6 months. Third stage larvae identical to these larvae were recovered from minnows experimentally fed L2 of P. tenerrima, and eels infected experimentally with naturally and experimentally infected minnows were found to harbour fourth stage larvae (L4) and juvenile P. tenerrima in their intestines. Finally, the whole life cycle from eggs to adult was completed in the laboratory, confirming that minnows are an obligate intermediate host for P. tenerrima.

ON THE FOURTH STAGE LARVA OF CHABERTIA OVINA

1936 ◽  
Vol 14d (11) ◽  
pp. 168-171
Author(s):  
Henry J. Griffiths
Keyword(s):  
Stage Larva ◽  
Fourth Stage ◽  
Common Parasite ◽  
Fourth Stage Larva

The structure of the early fourth stage larva of Chabertia ovina, a common parasite of ruminants, is described in detail.

LABORATORY STUDIES ON THE TOXICITY OF INSECTICIDES TO THE BERTHA ARMYWORM (MAMESTRA CONFIGURATA) (LEPIDOPTERA: NOCTUIDAE)

1975 ◽  
Vol 107 (8) ◽  
pp. 865-872 ◽  
Author(s):  
C. R. Harris ◽  
S.A. Turnbull
Keyword(s):  
Direct Contact ◽  
Developmental Stages ◽  
Contact Toxicity ◽  
Mamestra Configurata ◽  
Larval Stages ◽  
Large Numbers ◽  
Third Stage ◽  
History Of ◽  
Dual Objectives ◽  
Bertha Armyworm

AbstractThis study had dual objectives: to select a series of insecticides toxic to the bertha armyworm, Mamestra configurata (Walk.), and to determine susceptibility of the various developmental stages to insecticides. Pupae were collected from infested rapeseed fields in Alberta and a laboratory rearing procedure suitable for production of large numbers of insects was devised. The direct contact toxicity of 50 insecticides to third-stage larvae was assessed. Methomyl and DDT were included as standard insecticides. None of the experimental insecticides was as toxic as methomyl but about one half were more toxic than DDT. Tests with representative organochlorine, organophosphorus, and carbamate insecticides indicated that all caused rapid knockdown of third-stage larvae. There was no evidence of subsequent recovery. After the life history of the bertha armyworm under controlled environmental conditions was determined, tests were conducted to ascertain the susceptibility of the various developmental stages to methomyl, chlorpyrifos, leptophos, and methidathion. Eggs and first and second stage larvae were more susceptible to direct contact applications of the insecticides than were the later larval stages, pupae, and adults.

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