Nonrandom Association Patterns in Parasite Infections Caused by the Host Life Cycle: Empirical Evidence from Kudoa camarguensis (Myxosporea) and Aphalloides coelomicola (Trematoda)

2002 ◽  
Vol 88 (4) ◽  
pp. 817
Author(s):  
C. Pampoulie ◽  
S. Morand
Keyword(s):  
Life Cycle ◽  
Empirical Evidence ◽  
Association Patterns ◽  
Parasite Infections ◽  
Host Life

The Relationship between Advertising and Product Quality over the Product Life Cycle: A Contingency Theory

1988 ◽  
Vol 25 (1) ◽  
pp. 64-71 ◽  
Author(s):  
Gerard J. Tellis ◽  
Claes Fornell
Keyword(s):  
Life Cycle ◽  
Product Quality ◽  
Empirical Evidence ◽  
Product Life Cycle ◽  
Lower Cost ◽  
Empirical Test ◽  
Consumer Response ◽  
Product Life ◽  
Controversial Topic ◽  
The Relationship

The relationship between advertising and product quality has been a controversial topic in the literature because of conflicting empirical evidence and divergent theories about advertising's effects. The authors present an integrative theory based on consumer response to advertising and the costs of producing quality products. The theory posits that the relationship between advertising and quality is stronger when (1) quality is produced at lower cost and (2) consumers are less responsive to advertising. Such a scenario is more likely during the latter stages of the product life cycle. An empirical test supports this argument.

scholarly journals Amblyomma rotundatum (Koch, 1844) (Acari: Ixodidae) two-host life-cycle on Viperidae snakes

2010 ◽  
Vol 19 (3) ◽  
pp. 174-178 ◽  
Author(s):  
Daniel Sobreira Rodrigues ◽  
Ricardo Maciel ◽  
Lucas Maciel Cunha ◽  
Romário Cerqueira Leite ◽  
Paulo Roberto de Oliveira
Keyword(s):  
Life Cycle ◽  
North America ◽  
Relative Humidity ◽  
Total Duration ◽  
Ixodid Tick ◽  
Natural Conditions ◽  
South Central ◽  
Controlled Conditions ◽  
In Captivity ◽  
Host Life

Amblyomma rotundatum is an ixodid tick that infests ectothermic animals and reproduces exclusively by parthenogenesis. This tick has been frequently reported to infest reptiles and amphibians, under natural conditions and sometimes in captivity. It was described in Brazil and several other countries of South, Central and North America. Although many studies have reported aspects of its biology, none of them has used regularly either ophidian as hosts, or controlled temperature, humidity and luminosity for parasitic stages. The objective of this experiment was to study the life cycle of A. rotundatum feeding on Viperidae snakes under room controlled conditions at 27 ± 1 ºC temperature, 85 ± 10% relative humidity and 12:12 hours photoperiod for parasitic stages, and under B.O.D incubator conditions at 27 ± 1 ºC temperature, 85 ± 10% relative humidity and scotophase for non-parasitic stages. The total duration of the life cycle ranged from 56 to 163 days (mean of 105 days). Two-host life cycle was observed for most of the ixodid population studied.

Shortening of the PLC—AN Empirical Test

1981 ◽  
Vol 45 (4) ◽  
pp. 76-80 ◽  
Author(s):  
William Qualls ◽  
Richard W. Olshavsky ◽  
Ronald E. Michaels
Keyword(s):  
Life Cycle ◽  
Empirical Evidence ◽  
Product Life Cycle ◽  
Empirical Test ◽  
Growth Stages ◽  
Household Appliances ◽  
Product Life

Analysis of changes in the length of the introductory and growth stages of the product life cycle of 37 household appliances over a 50-year period provides the first empirical evidence for the commonly held assumption that the cycle's length is decreasing.

The demise of a class of protists: taxonomic and nomenclatural revisions proposed for the protest phylum Myxozoa Grassé, 1970

1994 ◽  
Vol 72 (5) ◽  
pp. 932-937 ◽  
Author(s):  
M. L. Kent ◽  
L. Margolis ◽  
J. O. Corliss
Keyword(s):  
Life Cycle ◽  
Tubifex Tubifex ◽  
Salmonid Fishes ◽  
Myxobolus Cerebralis ◽  
Aquatic Oligochaetes ◽  
As Species ◽  
Collective Group ◽  
Host Life ◽  
Myxosporean Species ◽  
Species Inquirendae

The phylum Myxozoa has been considered to comprise two classes, Myxosporea Bütschli, 1881 (primarily of fishes) and Actinosporea Noble in Levine et al., 1980 (primarily of aquatic oligochaetes). About 10 years ago it was demonstrated that the life cycle of Myxobolus cerebralis Hofer, 1903 (Myxobolidae: Platysporina) of salmonid fishes requires transformation of the myxosporean into an actinosporean stage in the oligochaete worm Tubifex tubifex (Tubificidae), and that the stage infective to fish is the actinosporean spore. This type of two-host life cycle has now been demonstrated or strongly implicated for 14 myxosporean species, belonging to 6 genera in 4 families. In light of these findings, the taxonomy of the Myxozoa is revised. We propose the following: suppression of the newer class Actinosporea and the order Actinomyxidia Štolc, 1899; and suppression of all families in the Actinosporea except Tetractinomyxidae. This family and its one genus, Tetractinomyxon Ikeda, 1912, are transferred to the order Multivalvulida Shulman, 1959 (Myxosporea). We also propose that actinosporean generic names be treated as collective-group names, thus they do not compete in priority with myxosporean generic names. Triactinomyxon dubium Granata, 1924 and Triactinomyxon gyrosalmo Wolf and Markiw, 1984 are suppressed as junior synonyms of Myxobolus cerebralis. The myxosporean stage of no other previously named actinosporean has been identified. Other actinosporean species are therefore retained as species inquirendae until their myxosporean stages are identified. A revised description of the phylum Myxozoa is provided that includes our proposed taxonomic and nomenclatural changes.

Encystment site affects the reproductive strategy of a progenetic trematode in its fish intermediate host: is host spawning an exit for parasite eggs?

Parasitology ◽  
2011 ◽  
Vol 138 (9) ◽  
pp. 1183-1192 ◽  
Author(s):  
KRISTIN K. HERRMANN ◽  
ROBERT POULIN
Keyword(s):  
Life Cycle ◽  
Intermediate Host ◽  
Body Cavity ◽  
Life Cycles ◽  
Temperature Changes ◽  
Fish Spawning ◽  
Second Intermediate Host ◽  
Host Life ◽  
Major Factors ◽  
Fish Hosts

SUMMARYEach transmission event in complex, multi-host life cycles create obstacles selecting for adaptations by trematodes. One such adaptation is life cycle abbreviation through progenesis, in which the trematode precociously matures and reproduces within the second intermediate host. Progenesis eliminates the need for the definitive host and increases the chance of life cycle completion. However, progenetic individuals face egg-dispersal challenges associated with reproducing within metacercarial cysts in the tissues or body cavity of the second intermediate host. Most progenetic species await host death for their eggs to be released into the environment. The present study investigated temporal variation of progenesis in Stegodexamene anguillae in one of its second intermediate fish hosts and the effect of the fish's reproductive cycle on progenesis. The study involved monthly sampling over 13 months at one locality. A greater proportion of individuals became progenetic in the gonads of female fish hosts. Additionally, progenesis of worms in the gonads was correlated with seasonal daylight and temperature changes, major factors controlling fish reproduction. Host spawning events are likely to be an avenue of egg dispersal for this progenetic species, with the adoption of progenesis being conditional on whether or not the parasite can benefit from fish spawning.

Plagioporus sinitsini (Digenea: Opecoelidae): A One-Host Life Cycle

2000 ◽  
Vol 86 (1) ◽  
pp. 150 ◽  
Author(s):  
Michael A. Barger ◽  
Gerald W. Esch
Keyword(s):  
Life Cycle ◽  
Host Life

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.

Using the giant Australian cuttlefish (Sepia apama) mass breeding aggregation to explore the life cycle of dicyemid parasites

2013 ◽  
Vol 58 (4) ◽  
Author(s):  
Sarah Catalano ◽  
Ian Whittington ◽  
Stephen Donnellan ◽  
Bronwyn Gillanders
Keyword(s):  
Life Cycle ◽  
South Australia ◽  
Life Cycle Stage ◽  
Maximum Amount ◽  
Energy Costs ◽  
Huge Number ◽  
Short Lifespan ◽  
Sepia Apama ◽  
Host Life ◽  
Seawater Samples

AbstractDicyemid mesozoan parasites, microscopic organisms found with high intensities in the renal appendages of benthic cephalopods, have a complex, partially unknown life cycle. It is uncertain at which host life cycle stage (i.e. eggs, juvenile, adult) new infection by the dispersive infusoriform embryo occurs. As adult cephalopods have a short lifespan and die shortly after reproducing only once, and juveniles are fast-moving, we hypothesize that the eggs are the life cycle stage where new infection occurs. Eggs are abundant and sessile, allowing a huge number of new individuals to be infected with low energy costs, and they also provide dicyemids with the maximum amount of time for survival compared with infection of juvenile and adult stages. In our study we collected giant Australian cuttlefish (Sepia apama) eggs at different stages of development and filtered seawater samples from the S. apama mass breeding aggregation area in South Australia, Australia, and tested these samples for the presence of dicyemid DNA. We did not recover dicyemid parasite cytochrome c oxidase subunit I (COI) nucleotide sequences from any of the samples, suggesting eggs are not the stage where new infection occurs. To resolve this unknown in the dicyemid life cycle, we believe experimental infection is needed.

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