Life cycle ofTrichostrongylus retortaeformisin its natural host, the rabbit (Oryctolagus cuniculus)

2002 ◽  
Vol 76 (3) ◽  
pp. 189-192 ◽  
Author(s):  
F. Audebert ◽  
H. Hoste ◽  
M.C. Durette-Desset
Keyword(s):  
Life Cycle ◽  
Oryctolagus Cuniculus ◽  
Life Cycles ◽  
Prepatent Period ◽  
Natural Host ◽  
Patent Period ◽  
Free Living ◽  
The Third ◽  
Significant Difference ◽  
The Relationship

AbstractThe chronology of the life cycle ofTrichostrongylus retortaeformis(Zeder, 1800) (Nematoda, Trichostrongyloidea) is studied in its natural hostOryctolagus cuniculus. The free living period lasted 5 days at 24°C. Worm-free rabbits were each infectedper oswithT. retortaeformislarvae. Rabbits were killed at 12 h post-infection (p.i.) and every day from one day to 13 days p.i. By 12 h p.i., all the larvae were exsheathed and in the small intestine. The third moult occurred between 3 and 5 days p.i. and the last moult between 4 and 7 days p.i. The prepatent period lasted 12 to 13 days. The patent period lasted five and a half months. The four known life cycles of species ofTrichostrongylusin ruminants were compared with that ofT. retortaeformis. No significant difference was found except in the duration of the prepatent period. These similarities in the life cycles confirm the previously formulated hypotheses on the relationship between the parasites of the two host groups ().

Temporal variation in the weight-size relationship of the mangrove crab Ucides cordatus L. (Decapoda: Ucididae) in relation to its life cycle phases

2014 ◽  
Vol 64 (4) ◽  
pp. 333-342 ◽  
Author(s):  
Marcos de Miranda Leão Leite ◽  
Cynthia Yuri Ogawa ◽  
Carla Ferreira Rezende ◽  
José Roberto Feitosa Silva
Keyword(s):  
Life Cycle ◽  
Condition Factor ◽  
River Estuary ◽  
Total Weight ◽  
Northeastern Brazil ◽  
Annual Life Cycle ◽  
Ucides Cordatus ◽  
Mangrove Crab ◽  
Significant Difference ◽  
The Relationship

The relationship between weight and size of individuals can be used to evaluate the status of a population, which is particularly useful for natural populations that are being exploited. Ucides cordatus occurs on the Atlantic coast of the American continent, from Florida (USA) to Santa Catarina (Brazil). This species is economically very important, most of all in the Northeastern area of Brazil, as well as in the Dominican Republic and Suriname. The objective of this study was to analyze life phases (‘fattening’, ‘matumba’, ‘milk-crab’, ‘maturation’ and ‘walking’) by use of the weight-length relationships, as well as temporal variations in this condition factor for each sex of U. cordatus. For this purpose, individuals were sampled monthly for twenty-four months at the Jaguaribe River estuary, Ceará State, Northeastern Brazil. The relationship between total weight and cephalothorax width was established using regression analysis, adjusted by a power equation. The dynamics of the condition factor were analyzed for each sex using the variation of its averages related to annual life cycle; this was done for each of the previously-mentioned phases. The relationship between total weight and cephalothorax width showed an isometric growth in males and negative allometric growth in females suggesting that, for the same reference size, males are heavier than females. When considering the average of the female condition factors, these were greater than those for males during the annual life cycle, except during the ‘maturation’ phase, which is the phase with a higher demand of energetic reserves for males. Annual variation of the condition factor in females presented no significant difference.

Observing microscopic phases of lichen life cycles on transparent substrata placed in situ

2005 ◽  
Vol 37 (5) ◽  
pp. 373-382 ◽  
Author(s):  
William B. SANDERS
Keyword(s):  
Life Cycle ◽  
Developmental Stages ◽  
Life Cycles ◽  
Potential Significance ◽  
Free Living ◽  
Lichen Community ◽  
One Year ◽  
The One ◽  
Observation Period

The utility of plastic cover slips as a substratum for in situ study of lichen developmental stages is further explored in a neotropical foliicolous lichen community and in a European temperate corticolous community. Twenty-one months after placement in the tropical forest, the cover slips bore foliicolous lichen thalli with several species producing characteristic ascocarps and ascospores, indicating the suitability of the substratum for completion of the life cycle of these lichens. On cover slips placed within the temperate corticolous community, lichen propagules anchored to the substratum with relatively short attachment hyphae but did not develop further within the one year observation period. Intimately intermixed microbial communities of short-celled, mainly pigmented fungi and chlorophyte algae developed upon the transparent substratum. Among the algae, Trebouxia cells, often in groups showing cell division and without associated lichenizing hyphae, were commonly observed. The potential significance of the free-living populations in the life cycle of Trebouxia and in those of Trebouxia-associated lichen fungi is discussed.

Autonomy and integration in complex parasite life cycles

Parasitology ◽  
2016 ◽  
Vol 143 (14) ◽  
pp. 1824-1846 ◽  
Author(s):  
DANIEL P. BENESH
Keyword(s):  
Life Cycle ◽  
Holistic Approach ◽  
Life Cycles ◽  
Complex Life Cycle ◽  
Functional Specialization ◽  
Life Stages ◽  
Free Living ◽  
New Host ◽  
Complex Life Cycles ◽  
Life Cycle Stages

SUMMARYComplex life cycles are common in free-living and parasitic organisms alike. The adaptive decoupling hypothesis postulates that separate life cycle stages have a degree of developmental and genetic autonomy, allowing them to be independently optimized for dissimilar, competing tasks. That is, complex life cycles evolved to facilitate functional specialization. Here, I review the connections between the different stages in parasite life cycles. I first examine evolutionary connections between life stages, such as the genetic coupling of parasite performance in consecutive hosts, the interspecific correlations between traits expressed in different hosts, and the developmental and functional obstacles to stage loss. Then, I evaluate how environmental factors link life stages through carryover effects, where stressful larval conditions impact parasites even after transmission to a new host. There is evidence for both autonomy and integration across stages, so the relevant question becomes how integrated are parasite life cycles and through what mechanisms? By highlighting how genetics, development, selection and the environment can lead to interdependencies among successive life stages, I wish to promote a holistic approach to studying complex life cycle parasites and emphasize that what happens in one stage is potentially highly relevant for later stages.

Life Cycles

2001 ◽  
Author(s):  
Jan A. Pechenik
Keyword(s):  
Life Cycle ◽  
Genetic Material ◽  
Life Cycles ◽  
Offspring Size ◽  
Free Living ◽  
Complex Life Cycles ◽  
Volume Number ◽  
Larval Stages ◽  
Underlying Mechanisms ◽  
Life Cycle Evolution

I have a Hardin cartoon on my office door. It shows a series of animals thinking about the meaning of life. In sequence, we see a lobe-finned fish, a salamander, a lizard, and a monkey, all thinking, “Eat, survive, reproduce; eat, survive, reproduce.” Then comes man: “What's it all about?” he wonders. Organisms live to reproduce. The ultimate selective pressure on any organism is to survive long enough and well enough to pass genetic material to a next generation that will also be successful in reproducing. In this sense, then, every morphological, physiological, biochemical, or behavioral adaptation contributes to reproductive success, making the field of life cycle evolution a very broad one indeed. Key components include mode of sexuality, age and size at first reproduction (Roff, this volume), number of reproductive episodes in a lifetime, offspring size (Messina and Fox, this volume), fecundity, the extent to which parents protect their offspring and how that protection is achieved, source of nutrition during development, survival to maturity, the consequences of shifts in any of these components, and the underlying mechanisms responsible for such shifts. Many of these issues are dealt with in other chapters. Here I focus exclusively on animals, and on a particularly widespread sort of life cycle that includes at least two ecologically distinct free-living stages. Such “complex life cycles” (Istock 1967) are especially common among amphibians and fishes (Hall and Wake 1999), and within most invertebrate groups, including insects (Gilbert and Frieden 1981), crustaceans, bivalves, gastropods, polychaete worms, echinoderms, bryozoans, and corals and other cnidarians (Thorson 1950). In such life cycles, the juvenile or adult stage is reached by metamorphosing from a preceding, free-living larval stage. In many species, metamorphosis involves a veritable revolution in morphology, ecology, behavior, and physiology, sometimes taking place in as little as a few minutes or a few hours. In addition to the issues already mentioned, key components of such complex life cycles include the timing of metamorphosis (i.e., when it occurs), the size at which larvae metamorphose, and the consequences of metamorphosing at particular times or at particular sizes. The potential advantages of including larval stages in the life history have been much discussed.

scholarly journals FORECASTING THE EFFICIENCY OF ELECTRICAL PRODUCTS TAKING INTO ACCOUNT THE STAGES OF THEIR LIFE CYCLE

2021 ◽  
pp. 63-70
Author(s):  
Alina Martynenko
Keyword(s):  
Life Cycle ◽  
Regression Model ◽  
Forecast Model ◽  
Life Cycles ◽  
Influential Factors ◽  
Consumer Value ◽  
Multifactor Regression ◽  
The Impact ◽  
The Relationship ◽  
Comprehensive Indicator

In the conditions of accelerated scientific and technological progress and social development, products can lose consumer value and, therefore, be ousted from the consumer market by other goods with a higher consumer value. In this regard, the importance of predicting product life cycles and their effectiveness is increasing. The aim of the article is to study the issue of forecasting the efficiency of electrical products taking into account the stages of their life cycle by constructing a multifactor regression model. The method of correlation-regression analysis was used to build a forecast model and determine the most influential factors for a particular motor, which determined the relationship between the comprehensive indicator and individual indicators of product efficiency. Thus, the article investigated the issue of forecasting the efficiency of electrical products taking into account the stages of their life cycle. On the example of the electric motor AIR 80 PJSC «Kharkiv Electrotechnical Plant «Ukrelectromash»» a multifactor regression model for the stage of decline is built, which includes the most important indicators of the impact on the comprehensive indicator of efficiency and allows to predict its dynamics.

scholarly journals Hubungan Siklus Hidup Perusahaan dan Manajemen Laba: Good Corporate Governance sebagai Variabel Moderating

2020 ◽  
Vol 3 (2) ◽  
pp. 158
Author(s):  
Suwarno Suwarno
Keyword(s):  
Corporate Governance ◽  
Life Cycle ◽  
Earnings Management ◽  
Structural Equation ◽  
Sampling Technique ◽  
Life Cycles ◽  
Equation Modeling ◽  
Management Actions ◽  
Good Corporate Governance ◽  
The Relationship

The purpose of this study is to determine the relationship of the corporate life cycles to earnings management and analyze Good Corporate Governance to moderate the relationship between the corporate life cycles with earnings management. This research use as quantitative approach using secondary data. The sampling technique uses purposive sampling method. The total sample used in this study were 75 company samples. The analysis technique used in this study is the Structural Equation Modeling-Partial Leasr Square (SEM-PLS) method using WarpPLS Version 5.0 Software. The results showed that the company’s life cycle variables influence earnings management and GCG can moderate the company’s life cycle relationship with earnings management so as to waked earnings management actions.

Seasonal variability in the gut ultrastructure of the parasitic copepod Neoergasilus japonicus (Copepoda, Poecilostomatoida)

2004 ◽  
Vol 82 (10) ◽  
pp. 1655-1666 ◽  
Author(s):  
A Baud ◽  
C Cuoc ◽  
J Grey ◽  
R Chappaz ◽  
V Alekseev
Keyword(s):  
Life Cycle ◽  
Stable Isotope ◽  
Physiological Activity ◽  
Parasitic Copepod ◽  
Free Living ◽  
The Family ◽  
Neoergasilus Japonicus ◽  
Structure And Ultrastructure ◽  
The Relationship ◽  
Isotope Analyses

The gut structure and ultrastructure of Neoergasilus japonicus (Harada, 1930), a copepod from the family Ergasilidae (Copepoda, Poecilostomatoida) and a parasite of fish, were compared at different periods of the life cycle: in free-living specimens in October and after attaching to fish in January and June. Differences in the depth of the intestinal epithelium were prominent and other cellular characteristics appeared seasonally variable. We relate these to changes in the physiological activity. Preliminary data from stable-isotope analyses of attached specimens suggest nutritional contribution from parasitism. The possibility of a diapause in the life cycle, as well as the relationship between the morphology of the gut and early evolutionary parasitism of N. japonicus, are discussed.

Research on Life Cycle Engineering Based on the Onstraint-Satisfaction Method

2012 ◽  
Vol 160 ◽  
pp. 190-194
Author(s):  
De Qiang Zhou
Keyword(s):  
Life Cycle ◽  
Environmental Protection ◽  
Life Cycles ◽  
Mutual Correlation ◽  
Life Cycle Engineering ◽  
Satisfactory Method ◽  
The Relationship

When researching on a global feasible products solutions, we need to consider the product of manipulation, practical, environmental protection, social demanding performances and so on. The several life cycles of a product determines and implements these performances.And the several cycles are mutual correlation, mutual restrict.Every link is crucial, so we must coordinate the relationship among them. The purpose of this paper is to simulate and solve the problem of life cycle by using different, restrictive,and satisfactory method.

EXPERIMENTAL STUDIES ON STRONGYLOIDES AGOUTII IN THE GUINEA PIG

1940 ◽  
Vol 18d (9) ◽  
pp. 307-324 ◽  
Author(s):  
Henry J. Griffiths
Keyword(s):  
Guinea Pig ◽  
Guinea Pigs ◽  
Mixed Type ◽  
Experimental Studies ◽  
Prepatent Period ◽  
Acquired Immunity ◽  
Patent Period ◽  
Free Living ◽  
Mode Of Development ◽  
One Year

The suitability and tolerance of the guinea pig to infection with Strongyloides agoutii presented an opportunity for the study of the bionomics of this species in an experimental host.Serial transfer of this nematode through the guinea pig yielded a mixed type (free males and filariform larvae) of free-living development in faecal cultures which occasionally reverted to the indirect mode common to S. agoutii. A reversion to the indirect mode of development was produced when ova from faeces of guinea pigs infected with S. agoutii were cultured in sterile agouti faeces.The termination of the prepatent period of S. agoutii in the guinea pig was shown to range from 7 to 10 days, and 71% of 58 animals were positive by faecal test by the eighth day. The patent period ranged from three to eight weeks.The guinea pig was shown to develop an absolute acquired immunity to re-infection with S. agoutii. This resistance has been retained over a period of at least 6 to 13 months. An age resistance was not observed in animals one year old and over.

The first known riodinid ‘cuckoo’ butterfly reveals deep-time convergence and parallelism in ant social parasites

2020 ◽  
Author(s):  
Lucas A Kaminski ◽  
Luis Volkmann ◽  
Curtis J Callaghan ◽  
Philip J DeVries ◽  
Roger Vila
Keyword(s):  
Life Cycle ◽  
Social Parasitism ◽  
Social Parasites ◽  
Free Living ◽  
Deep Time ◽  
The Third ◽  
The Family ◽  
History Of ◽  
Ant Nest ◽  
Evolutionary Pathways

Abstract Mutualistic interactions between butterflies and ants can evolve into complex social parasitism. ‘Cuckoo’ caterpillars, known only in the Lycaenidae, use multimodal mimetic traits to achieve social integration into ant societies. Here, we present the first known ‘cuckoo’ butterfly in the family Riodinidae. Aricoris arenarum remained in taxonomic limbo for > 80 years, relegated to nomen dubium and misidentified as Aricoris gauchoana. We located lost type material, designated lectotypes and documented the morphology and natural history of the immature stages. The multifaceted life cycle of A. arenarum can be summarized in three phases: (1) females lay eggs close to honeydew-producing hemipterans tended by specific Camponotus ants; (2) free-living caterpillars feed on liquids (honeydew and ant regurgitations); and (3) from the third instar onward, the caterpillars are fed and tended by ants as ‘cuckoos’ inside the ant nest. This life cycle is remarkably similar to that of the Asian lycaenid Niphanda fusca, despite divergence 90 Mya. Comparable eco-evolutionary pathways resulted in a suite of ecomorphological homoplasies through the ontogeny. This study shows that convergent interactions can be more important than phylogenetic proximity in shaping functional traits of social parasites.

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