Life History Studies on Trematodes of the Subfamily Reniferinae

Parasitology ◽  
1933 ◽  
Vol 25 (4) ◽  
pp. 518-545 ◽  
Author(s):  
S. Benton Talbot
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Life Histories ◽  
Life Cycles ◽  
Small Fish ◽  
Intermediate Hosts ◽  
Natural Group ◽  
Remarkable Similarity ◽  
Physella Gyrina ◽  
Mother Sporocyst

1. The life histories of Lechriorchis primus Stafford, L. tygarti n.sp. and Caudorchis eurinus n.gen. et sp. have been experimentally completed in three hosts, the first complete life histories to be worked out for species of the subfamily Reniferinae.2. The definitive hosts of the three forms were found to be two species of garter snakes, Thamnophis sauritus and T. sirtalis.3. Three species of snails, Physella gyrina, P. parkeri, and P. ancillaria, have been found to serve as the first intermediate host in the life cycles of Lechriorchis primus and Caudorchis eurinus n.gen. et sp., and two species of snails, Physella gyrina and P. heterostropha, in the life cycle of Lechriorchis tygarti n.sp.4. The tadpoles of two species of frogs, Rana clamitans and R. pipiens, were found to serve as the second intermediate hosts in the life cycles of all three trematodes. The cercariae penetrate larvae of Triturus and small fish, but live only a short time in these animals.5. Every stage in the life history of Lechriorchis primus, including egg, miracidium, mother sporocyst, daughter sporocyst, cercaria, metacercaria, and developmental stages in the definitive host, has been described in detail.6. The mother sporocyst of forms having a stylet cercaria is described for the first time.7. The flame cell pattern of the cercariae of L. primus, L. tygarti n.sp., and Caudorchis eurinus n.gen. et sp. has been determined to be of the “2 × 6 × 3’ type. Also the adult stage of C. eurinus was determined to have the same type.8. It has been pointed out that the life histories of the members of the subfamily are uniform in that their life history stages display a remarkable similarity.9. It has been suggested that this uniform type of life cycle and remarkable similarity of larval stages offer the most logical basis for establishing the subfamily Reniferinae as a natural group.

Coevolutionary interactions between host life histories and parasite life cycles

Parasitology ◽  
1998 ◽  
Vol 116 (S1) ◽  
pp. S47-S55 ◽  
Author(s):  
J. C. Koella ◽  
P. Agnew ◽  
Y. Michalakis
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Life Histories ◽  
Life History Traits ◽  
Evolutionary Ecology ◽  
Life Cycles ◽  
Microsporidian Parasite ◽  
History Of ◽  
Host Life ◽  
Host Parasite

SummarySeveral recent studies have discussed the interaction of host life-history traits and parasite life cycles. It has been observed that the life-history of a host often changes after infection by a parasite. In some cases, changes of host life-history traits reduce the costs of parasitism and can be interpreted as a form of resistance against the parasite. In other cases, changes of host life-history traits increase the parasite's transmission and can be interpreted as manipulation by the parasite. Alternatively, changes of host's life-history traits can also induce responses in the parasite's life cycle traits. After a brief review of recent studies, we treat in more detail the interaction between the microsporidian parasite Edhazardia aedis and its host, the mosquito Aedes aegypti. We consider the interactions between the host's life-history and parasite's life cycle that help shape the evolutionary ecology of their relationship. In particular, these interactions determine whether the parasite is benign and transmits vertically or is virulent and transmits horizontally.Key words: host-parasite interaction, life-history, life cycle, coevolution.

Challenges for Diadromous Fishes in a Dynamic Global Environment

2009 ◽  
Keyword(s):  
Life Cycle ◽  
Life Histories ◽  
Life Cycles ◽  
Partial Migration ◽  
Environmental Stochasticity ◽  
Species Dynamics ◽  
Life Cycle Pattern ◽  
Aquatic Sciences ◽  
Diversity Of Life

<em>Abstract</em>.-In the study of species life histories and the structure of diadromous populations, an emerging trend is the prevalence of life cycle diversity-that is, individuals within populations that do not conform to a single life cycle pattern. A rapid rise in publications documenting within-population variability in life cycles has resulted in the use of numerous terms and phrases. We argue that myriad terms specific to taxa, ecosystem types, and applications are in fact describing the same phenomenon-life cycle diversity. This phenomenon has been obscured by the use of multiple terms across applications, but also by the overuse of typologies (i.e., anadromy, catadromy) that fail to convey the extent of life cycle variations that underlay population, metapopulation, and species dynamics. To illustrate this, we review migration and habitat-use terms that have been used to describe life cycles and life cycle variation. Using a citation index (Cambridge Scientific Abstracts © Aquatic Sciences and Fisheries Abstracts), terms were tallied across taxonomic family, ecosystem, type of application, analytical approach, and country of study. Studies on life cycle diversity have increased threefold during the past 15 years, with a total of 336 papers identified in this review. Most of the 40 terms we identified described either sedentary or migratory lifetime behaviors. The sedentary-migratory dichotomy fits well with the phenomenon of partial migration, which has been commonly reported for birds and Salmonidae and is postulated to be the result of early life thresholds (switch-points). On the other hand, the lexicon supports alternate modes of migration, beyond the simple sedentary-migratory dichotomy. Here more elaborate causal mechanisms such as the entrainment hypothesis may have application. Diversity of life cycles in fish populations, whether due to partial migration, entrainment, or other mechanisms, is increasingly recognized as having the effect of offsetting environmental stochasticity and contributing to long-term persistence.

scholarly journals Endocrine Control of Life-Cycle Stages: A Constraint on Response to the Environment?

The Condor ◽  
2000 ◽  
Vol 102 (1) ◽  
pp. 35-51 ◽  
Author(s):  
Jerry D. Jacobs ◽  
John C. Wingfield
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Control Systems ◽  
Life Cycles ◽  
Environmental Cues ◽  
Endocrine Control ◽  
Theoretical Approaches ◽  
Life Cycle Stages ◽  
Wide Range ◽  
Breeding Seasons

Abstract Most organisms live in seasonal environments that fluctuate on a predictable schedule and sometimes unpredictably. Individuals must, therefore, adjust so as to maximize their survival and reproductive success over a wide range of environmental conditions. In birds, as in other vertebrates, endocrine secretions regulate morphological, physiological, and behavioral changes in anticipation of future events. The individual thus prepares for predictable fluctuations in its environment by changing life-cycle stages. We have applied finite-state machine theory to define and compare different life-history cycles. The ability of birds to respond to predictable and unpredictable regimes of environmental variation may be constrained by the adaptability of their endocrine control systems. We have applied several theoretical approaches to natural history data of birds to compare the complexity of life cycles, the degree of plasticity of timing of stages within the cycle, and to determine whether endocrine control mechanisms influence the way birds respond to their environments. The interactions of environmental cues on the timing of life-history stages are not uniform in all populations. Taking the reproductive life-history stage as an example, arctic birds that have short breeding seasons in severe environments appear to use one reliable environmental cue to time reproduction and they ignore other factors. Birds having longer breeding seasons exhibit greater plasticity of onset and termination and appear to integrate several environmental cues. Theoretical approaches may allow us to predict how individuals respond to their environment at the proximate level and, conversely, predict how constraints imposed by endocrine control systems may limit the complexity of life cycles.

The Life-Cycle and Morphology of Stemmatostoma-Pearsoni, Gen Et Sp-Nov, With Notes on the Morphology of Telogaster-Opisthorchis Macfarlane (Digenea, Cryptogonimidae)

1986 ◽  
Vol 34 (2) ◽  
pp. 279 ◽  
Author(s):  
TH Cribb
Keyword(s):  
Life Cycle ◽  
Intermediate Host ◽  
Freshwater Fish ◽  
Oral Sucker ◽  
Intermediate Hosts ◽  
Redial Generation ◽  
Adult Morphology ◽  
Mother Sporocyst ◽  
First Intermediate Host ◽  
Prosobranch Snail

Stemmatostoma pearsoni, gen. et sp. nov., is described from the intestine of Leiopotherapon unicolor (Gunther) and Macquaria novemaculeata (Steindachner) in Queensland. Stemmatostoma is placed within the Neochasminae and is distinguished by its long oesophagus, compact ovary, short caeca, pre-ovarian vitellaria, simple gonotyl and funnel-shaped oral sucker. The diagnosis of the Neochasminae is emended excluding Parspina Pearse. Telogaster opisthorchis Macfarlane is recorded from the intestine of Anguilla reinhardtii Steindachner from Victoria. The spinose oral suckers of S. pearsoni and T. opisthorchis are capable of being retracted into tegumental pockets. It is postulated that this arrangement may be widespread amongst spinose cryptogonimids. The first intermediate host of S. pearsoni is Posticobia brazieri (Smith), a prosobranch snail. The second intermediate hosts are freshwater fish: Hypseleotris galii (Ogilby), H. compressus (Krefft), Mogurnda mogurnda (Richardson), M. adspersa (Castelnau), Philypnodon grandiceps (Krefft), Gobiomorphus australis (Krefft), and Pseudomugil signifer Kner. Within the snail there is a mother sporocyst generation, a redial generation and a cercarial generation. Development of the mother sporocyst is similar to that described for other opisthorchioids. Cryptogonimid cercariae are characterized by 16 flame-cells, pre-vesicular penetration glands, dorso-ventral caudal finfolds and absence of body pigmentation. On the basis of cercarial and adult morphology it is proposed that Pseudexorchis Yamaguti be excluded from the Cryptogonimidae.

Life history variation in plants: an exploration of the fast-slow continuum hypothesis

1996 ◽  
Vol 351 (1345) ◽  
pp. 1341-1348 ◽  
Keyword(s):  
Life History ◽  
Life Histories ◽  
Sexual Maturity ◽  
Life History Traits ◽  
Continuum Hypothesis ◽  
Adult Mortality ◽  
Life Cycles ◽  
Differential Mortality ◽  
Life History Variation ◽  
Net Reproductive Rate

Several empirical models have attempted to account for the covariation among life history traits observed in a variety of organisms. One of these models, the fast-slow continuum hypothesis, emphasizes the role played by mortality at different stages of the life cycle in shaping the large array of life history variation. Under this scheme, species can be arranged from those suffering high adult mortality levels to those undergoing relatively low adult mortality. This differential mortality is responsible for the evolution of contrasting life histories on either end of the continuum. Species undergoing high adult mortality are expected to have shorter life cycles, faster development rates and higher fecundity than those experiencing lower adult mortality. The theory has proved accurate in describing the evolution of life histories in several animal groups but has previously not been tested in plants. Here we test this theory using demographic information for 83 species of perennial plants. In accordance with the fast-slow continuum, plants undergoing high adult mortality have shorter lifespans and reach sexual maturity at an earlier age. However, demographic traits related to reproduction (the intrinsic rate of natural increase, the net reproductive rate and the average rate of decrease in the intensity of natural selection on fecundity) do not show the covariation expected with longevity, age at first reproducion and life expectancy at sexual maturity. Contrary to the situation in animals, plants with multiple meristems continuously increase their size and, consequently, their fecundity and reproductive value. This may balance the negative effect of mortality on fitness, thus having no apparent effect in the sign of the covariation between these two goups of life history traits.

The Life-history of a Marine Trematode, Hamacreadium Mutabile Linton, 1910

Parasitology ◽  
1929 ◽  
Vol 21 (1-2) ◽  
pp. 220-225 ◽  
Author(s):  
Oliver R. McCoy
Keyword(s):  
Life History ◽  
General Relationship ◽  
Small Fish ◽  
Intermediate Hosts ◽  
Marine Snail ◽  
Pyloric Caeca ◽  
The Family ◽  
History Of ◽  
Relationship Of ◽  
Gray Snapper

A cotylocercous cercaria occurring in the marine snail, Astraea americana, at Tortugas, Florida, was found to encyst in small fish as second intermediate hosts.Fish experimentally infested with the cysts were fed to the gray snapper, Neomaenis griseus, and adult worms developed in the intestine and pyloric caeca which were identified as Hamacreadium mutabile Linton, 1910, a member of the sub-family Allocreadiinae.A general relationship of the cotylocercous cercariae to the family Allocreadiidae is discussed.

scholarly journals The helminth infracommunities of the wood mouse (Apodemus sylvaticus) two years after the fire in Mediterranean forests

2013 ◽  
Vol 50 (1) ◽  
pp. 27-38 ◽  
Author(s):  
I. Torre ◽  
A. Arrizabalaga ◽  
C. Feliu ◽  
A. Ribas
Keyword(s):  
Species Richness ◽  
Life Cycle ◽  
Wood Mouse ◽  
Final Host ◽  
Life Cycles ◽  
Helminth Species ◽  
Mediterranean Forests ◽  
Intermediate Hosts ◽  
Wood Mice ◽  
Short Period

AbstractParasites have been recognized as indicators for natural or man-induced environmental stress and perturbation. In this article, we investigated the role of two non-exclusive hypotheses on the response of helminths of wood mice to fire perturbation: 1) a reduction of the helminth infracommunity (species richness) in post-fire areas due to the temporal lack of worms with indirect (complex) life cycles linked to intermediate hosts that are more specialized than the final host, and 2) an increase of the abundance of helminths with direct (simple) life cycles as a response of increasing abundances of the final host, may be in stressful conditions linked to the post-fire recolonization process.We studied the helminth infracommunities of 97 wood mice in two recently burned plots (two years after the fire) and two control plots in Mediterranean forests of NE Spain. Species richness of helminths found in control plots (n = 14) was twice large than in burned ones (n = 7). Six helminth species were negatively affected by fire perturbation and were mainly or only found in unburned plots. Fire increased the homogeneity of helminth infracommunities, and burned plots were characterised by higher dominance, and higher parasitation intensity. We found a gradient of frequency of occurrence of helminth species according to life cycle complexity in burned areas, being more frequent monoxenous (66.6 %), than diheteroxenous (33.3 %) and triheteroxenous (0 %), confirming the utility of helminths as bioindicators for ecosystem perturbations. Despite the short period studied, our results pointed out an increase in the abundance and prevalence of some direct life cycle helminths in early postfire stages, whereas indirect life cycle helminths were almost absent. A mismatch between the final host (that showed a fast recovery shortly after the fire), and the intermediate hosts (that showed slow recoveries shortly after the fire), was responsible for the loss of half of the helminth species.

Experimental life-cycle studies of Raillietiella gehyrae Bovien, 1927 and Raillietiella frenatus Ali, Riley and Self, 1981: pentastomid parasites of geckos utilizing insects as intermediate hosts

Parasitology ◽  
1983 ◽  
Vol 86 (1) ◽  
pp. 147-160 ◽  
Author(s):  
J. H. Ali ◽  
J. Riley
Keyword(s):  
Life Cycle ◽  
Early Development ◽  
Post Infection ◽  
Egg Production ◽  
Fat Body ◽  
Life Cycles ◽  
Stage Larva ◽  
Intermediate Hosts ◽  
Selective Filter ◽  
Complete Development

SUMMARYThe life-cycles of two closely related cephalobaenid pentastomids, Raillietiella gehyrae and Raillietiella frenatus, which utilize geckos as definitive hosts and cockroaches as intermediate hosts, have been investigated in detail. Early development in the fat-body of cockroaches involves 2 moults to an infective, 3rd-stage larva which appears from 42–44 days post-infection. Complete development in geckos involves a further 5 moults in the case of males and 6 for females. Males mature precociously and copulation is a once-in-a-lifetime event which occurs around day 80 post-infection when both sexes are the same size but the uterus of the female is undeveloped. Sperm, stored in the spermathecae, is used to fertilize oocytes which slowly accumulate in the developing saccate uterus. Patency commences when the uterus carries approximately 4000–5500 eggs but only 25–36 % of these contain fully developed primary larvae. Since only mature eggs are deposited, we postulate that the vagina (?) of the female must be equipped with a selective filter that allows through large eggs but retains smaller, immature eggs. Thus the only limit on fecundity is the total number of sperms in the spermathecae and this is precisely the same factor that constrains egg production in the advanced order Porocephalida.

scholarly journals Circulation Pathways of Trematodes of Freshwater Gastropod Mollusks in Forest Biocenoses of the Ukrainian Polissia

2019 ◽  
Vol 53 (1) ◽  
pp. 13-22 ◽  
Author(s):  
E. P. Zhytova ◽  
L. D. Romanchuk ◽  
S. V. Guralska ◽  
O. Yu. Andreieva ◽  
M. V. Shvets
Keyword(s):  
Life Cycle ◽  
Life Cycles ◽  
Trematode Species ◽  
Intermediate Hosts ◽  
Alaria Alata ◽  
Gastropod Mollusks ◽  
Second Intermediate Host ◽  
Host Life ◽  
Taxonomic Groups ◽  
Diversity Of Life

Abstract This is the first review of life cycles of trematodes with parthenitae and larvae in freshwater gastropods from forest biocoenoses of Ukrainian Polissia. Altogether 26 trematode species from 14 families were found circulating in 13 ways in molluscs from reservoirs connected with forest ecosystems of the region. Three-host life cycle is typical of 18 trematode species, two-host life cycle has found in 7 species, and four-host cycles has found in one species. Alaria alata Goeze, 1782, has three-host (Shults, 1972) and four-host cycles. Opisthioglyphe ranae (Froehlich, 1791) can change three-host life cycle to two-host cycle replacing the second intermediate host (Niewiadomska et al., 2006) with the definitive host. Species with primary two-host life cycle belong to Notocotylidae Lühe, 1909, Paramphistomidae Fischoeder, 1901 and Fasciolidae Railliet, 1758 families. Trematodes with three-host cycle have variable second intermediate hosts, including invertebrates and aquatic or amphibious vertebrates. Definitive hosts of trematodes are always vertebrates from different taxonomic groups. The greatest diversity of life cycles is typical for trematodes of birds. Trematodes in the forest biocoenoses of Ukrainian Polissia infect birds in six ways, mammals in three, amphibians in four, and reptiles in one way. The following species have epizootic significance: Liorchis scotiae (Willmott, 1950); Parafasciolopsis fasciolaemorpha Ejsmont, 1932; Notocotylus seineti Fuhrmann, 1919; Catatropis verrucosa (Frölich, 1789) Odhner, 1905; Cotylurus cornutus (Rudolphi, 1808); Echinostoma revolutum (Fröhlich, 1802) Dietz, 1909; Echinoparyphium aconiatum Dietz, 1909; Echinoparyphium recurvatum (Linstow, 1873); Hypoderaeum conoideum (Bloch, 1782) Dietz, 1909; Paracoenogonimus ovatus Kasturada, 1914; Alaria alata Goeze, 1782.

The Experimental Production of Life Cycles in Ciliates

1930 ◽  
Vol 7 (2) ◽  
pp. 132-142
Author(s):  
HUGH H. DARBY
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Culture Medium ◽  
Life Cycles ◽  
Ion Concentration ◽  
Experimental Production ◽  
Optimum Conditions ◽  
Gradual Decline ◽  
Division Rate

Constant division rate in ciliates can be maintained by keeping the culture medium at constant optimum H-ion concentration. The variations in division rate found in the typical protozoan life history, including gradual decline and death, can be reproduced experimentally by altering the pH of the medium. When cultures are maintained under optimum conditions, encystment and conjugation can take place at any age; the life cycle disappears. An explanation based on experiment is given for the apparently contradictory findings of Maupas. Neither conjugation nor endomixis has any effect on the division rate under constant conditions. The length of the endomictic period is affected by the H-ion concentration of the medium.

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