Variation in life-history traits of Plasmodium mexicanum, a malaria parasite infecting western fence lizards: a longitudinal study

2000 ◽  
Vol 78 (7) ◽  
pp. 1230-1237 ◽  
Author(s):  
Rebecca J Eisen
Keyword(s):  
Growth Rate ◽  
Life History ◽  
Growth Rates ◽  
Life History Traits ◽  
Warm Season ◽  
Host Population ◽  
Sand Fly ◽  
Infected Host ◽  
Average Growth ◽  
History Of

The life history of malaria parasites (Plasmodium spp.) is directly related to their transmission, virulence, and population dynamics. I followed the life history of Plasmodium mexicanum in naturally infected western fence lizards (Sceloporus occidentalis) over a 4-year period, using a mark-recapture technique. The life-history traits measured included peak parasitemias and population growth rates of asexual forms, gametocytes, and total parasites. Among malaria infections, variation was high for all measured traits. Growth rates varied up to 11-fold, and among stable infections, average asexual parasitemias ranged from 0.2 to 13.2 and gametocytemias from 0.5 to 66.2 parasites per 1000 erythrocytes. This variation was not related to infection prevalences, which were similar among years and between male and female hosts. Host age and gender were not related to peak parasitemia or average growth rate of asexual forms. However, the growth rate of gametoctyes was higher in older lizards. Gametocytemia and parasitemia were significantly higher late in the warm season, when sand-fly vectors are active. These data reveal that life-history traits of P. mexicanum are highly variable within an infected host population, and that the variation is partially related to the age of the infected host or the time of year the host was examined.

scholarly journals Asexual reproduction and growth rate: independent and plastic life history traits in Neurospora crassa

2018 ◽  
Vol 13 (3) ◽  
pp. 780-788 ◽  
Author(s):  
Jennifer L. Anderson ◽  
Bart P. S. Nieuwenhuis ◽  
Hanna Johannesson
Keyword(s):  
Growth Rate ◽  
Life History ◽  
Neurospora Crassa ◽  
Asexual Reproduction ◽  
Life History Traits

Life history and environmental influences on population dynamics in sockeye salmon

2014 ◽  
Vol 71 (8) ◽  
pp. 1198-1208 ◽  
Author(s):  
Douglas C. Braun ◽  
John D. Reynolds
Keyword(s):  
Population Dynamics ◽  
Life History ◽  
Population Growth ◽  
Growth Rates ◽  
Environmental Conditions ◽  
Sockeye Salmon ◽  
Life History Traits ◽  
Relative Importance ◽  
Population Growth Rates ◽  
Habitat Variables

Understanding linkages among life history traits, the environment, and population dynamics is a central goal in ecology. We compared 15 populations of sockeye salmon (Oncorhynchus nerka) to test general hypotheses for the relative importance of life history traits and environmental conditions in explaining variation in population dynamics. We used life history traits and habitat variables as covariates in mixed-effect Ricker models to evaluate the support for correlates of maximum population growth rates, density dependence, and variability in dynamics among populations. We found dramatic differences in the dynamics of populations that spawn in a small geographical area. These differences among populations were related to variation in habitats but not life history traits. Populations that spawned in deep water had higher and less variable population growth rates, and populations inhabiting streams with larger gravels experienced stronger negative density dependence. These results demonstrate, in these populations, the relative importance of environmental conditions and life histories in explaining population dynamics, which is rarely possible for multiple populations of the same species. Furthermore, they suggest that local habitat variables are important for the assessment of population status, especially when multiple populations with different dynamics are managed as aggregates.

Early Life History of Fishes in the San Francisco Estuary and Watershed

2004 ◽  
Keyword(s):  
Growth Rate ◽  
San Francisco ◽  
Striped Bass ◽  
Growth Rates ◽  
Early Life History ◽  
San Francisco Estuary ◽  
Annual Growth ◽  
Factors Affecting ◽  
Juvenile Abundance ◽  
History Of

<em>Abstract.</em>—We investigated factors affecting growth of larval striped bass <em>Morone saxatilis </em>in the San Francisco Estuary from 1984 to 1993. We estimated ages and growth rates of larval striped bass from daily otolith increments. Mean annual growth rates of 6–14 mm standard length striped bass varied from 0.13 to 0.27mm/d, the lowest rate occurring in 1989 and the highest in 1992. The 1989 growth rate was significantly lower than all other years, and growth rates for 1992 and 1993 were significantly higher than all other years, but did not differ from one another. Differences in annual growth rates apparently were due mainly to differences in mean annual prey densities because growth rate increased as prey density increased. Compared to both laboratory measured growth rates and growth rates of field-caught Chesapeake Bay larvae, growth rates from the San Francisco Estuary appeared to be high for the food available, indicating that larvae can grow at relatively high rates even at low prey densities. Correlation analyses did not support density-dependent control of growth rates. Growth rate was not significantly related to mean annual conductivity, water temperature, mortality rates, or the juvenile abundance index, but was significantly and positively correlated with densities of 1-mm length-groups of 9–14-mm striped bass.

scholarly journals Life history traits of the temperate mini-maximalist Idiosepius notoides, (Cephalopoda: Sepioidea)

2003 ◽  
Vol 83 (6) ◽  
pp. 1297-1300 ◽  
Author(s):  
Sean R. Tracey ◽  
Mike A. Steer ◽  
Gretta T. Pecl
Keyword(s):  
Life History ◽  
Growth Rates ◽  
Sexual Maturity ◽  
Life History Traits ◽  
Mantle Length ◽  
Power Curve ◽  
Short Life ◽  
Gender Dimorphism ◽  
Cephalopod Species

Age, growth and maturation of the temperate ‘mini-maximalist’ Idiosepius notoides from Tasmania is described and compared with those of its tropical congener Idiosepius pygmaeus. Using statolith increment analysis, growth of I. notoides was best described by a power curve with a maximum age of 115 days recorded. Males have a shorter lifespan than females, however growth rates were similar between the sexes. Idiosepius notoides grows to a larger size than its tropical counterpart. Onset of maturity in I. notoides occurred at an age of approximately 68 days for males and 88 days for females compared to 45–60 days for I. pygmaeus. Size at onset of sexual maturity was analogous between the two species, with males mature at approximately 6·5 mm mantle length (ML) and females at 14·0 mm ML. Idiosepius notoides, like I. pygmaeus, is a small short-lived sepioid with significant gender dimorphism and the capacity to spawn multiple times throughout its short life. This research supports the concept of similar cephalopod species living longer and growing larger in cooler environments.

scholarly journals Erratum to: Life-history traits of Amur sleeper, Perccottus glenii, in the invaded Vistula River: early investment in reproduction but reduced growth rate

Hydrobiologia ◽  
2011 ◽  
Vol 683 (1) ◽  
pp. 311-311
Author(s):  
Joanna Grabowska ◽  
Dariusz Pietraszewski ◽  
Mirosław Przybylski ◽  
Ali Serhan Tarkan ◽  
Lidia Marszał ◽  
...  
Keyword(s):  
Growth Rate ◽  
Life History ◽  
Life History Traits ◽  
Amur Sleeper ◽  
Perccottus Glenii ◽  
Vistula River ◽  
Investment In Reproduction

The Natural History of Incidental Meningiomas

Neurosurgery ◽  
2003 ◽  
Vol 53 (1) ◽  
pp. 62-71 ◽  
Author(s):  
Makoto Nakamura ◽  
Florian Roser ◽  
Julia Michel ◽  
Cornelius Jacobs ◽  
Madjid Samii
Keyword(s):  
Growth Rate ◽  
Natural History ◽  
Tumor Growth ◽  
Growth Rates ◽  
Tumor Size ◽  
Annual Growth ◽  
Tumor Doubling Time ◽  
History Of ◽  
Doubling Times ◽  
Initial Tumor Size

Abstract OBJECTIVE Little information about the natural history of incidental meningiomas exists in the literature. The aim of this study was to determine the natural history of asymptomatic meningiomas by comparing different methods of growth rate calculation to establish a strategy for dealing with these tumors. METHODS In 47 asymptomatic patients, hospital charts, follow-up records, and imaging studies were reviewed. Of these patients, 6 underwent surgery. Tumor growth rates were determined by calculating the absolute and relative growth rates and the tumor volume doubling times. RESULTS In 41 patients with conservative management, the average tumor size was 9 cm3, and the majority (66%) of growth rates were less than 1 cm3/yr. The absolute growth rate ranged from 0.03 to 2.62 cm3/yr (mean, 0.796 cm3/yr). Relative annual growth rates ranged from 0.48 to 72.8% (mean, 14.6%). The tumor doubling time ranged from 1.27 to 143.5 years (mean, 21.6 yr). A moderate correlation between the age and growth rates was found. In young patients, annual growth rates tended to be higher and tumor doubling times shorter. There was no clear correlation between the initial tumor size and tumor doubling time. The mean annual growth rate of meningiomas with calcification was lower than in tumors without calcification. Also, tumors with hypointense or isointense T2 signals on magnetic resonance imaging had a lower growth rate. In the group of six patients with surgical excision, tumor growth rates were higher and tumor doubling times shorter than in the nonsurgical group. CONCLUSION The majority of incidental meningiomas show minimal growth; thus, they may be observed without surgical intervention unless specific symptoms appear. Tumor growth is associated with patient age. The initial tumor size is not considered a predictive factor for tumor growth. Radiological features, such as calcification or T2 signal intensity, may provide useful information to predict the growth potential of meningiomas.

scholarly journals Life history of a secondary bark beetle, Pseudips mexicanus (Coleoptera: Curculionidae: Scolytinae), in lodgepole pine in British Columbia

2009 ◽  
Vol 141 (1) ◽  
pp. 56-69 ◽  
Author(s):  
G.D. Smith ◽  
A.L. Carroll ◽  
B.S. Lindgren
Keyword(s):  
Life History ◽  
Bark Beetle ◽  
Pinus Contorta ◽  
Life History Traits ◽  
Lodgepole Pine ◽  
Degree Days ◽  
Northern Portion ◽  
History Of ◽  
Bark Beetle Associates

AbstractPseudips mexicanus (Hopkins) is a secondary bark beetle native to western North and Central America that attacks most species of pine (Pinus L. (Pinaceae)) within its range. A pair of life-history studies examined P. mexicanus in other host species, but until now, no work has been conducted on lodgepole pine (Pinus contorta Douglas ex Louden var. latifolia Engelm. ex S. Watson). Pseudips mexicanus in lodgepole pine was found to be polygynous. Galleries were shorter, offspring smaller, and the eggs laid per niche and the potential progeny fewer than in populations from California and Guatemala. Development from the time of female attack to emergence of adult offspring took less than 50 days at 26.5 °C, and the accumulated heat required to complete the life cycle was determined to be 889.2 degree days above 8.5 °C, indicating that in the northern portion of its range P. mexicanus is univoltine. Determination of these life-history traits will facilitate study of interactions between P. mexicanus and other bark beetle associates in lodgepole pine.

Life history, demography, diet and habitat associations in the southwestern earless lizard, Cophosaurus texanus scitulus from northern and southern limits of its geographical range

2007 ◽  
Vol 28 (1) ◽  
pp. 65-76 ◽  
Author(s):  
Fred Punzo
Keyword(s):  
Life History ◽  
Growth Rates ◽  
Diet Composition ◽  
Life History Traits ◽  
Geographic Range ◽  
Habitat Associations ◽  
Generalist Predators ◽  
Reproductive Condition ◽  
Age Classes ◽  
Adult Age

AbstractI studied life history traits, demography, diet composition and habitat associations in the southwestern earless lizard, Cophosaurus texanus scitulus. Individuals from various age classes were sampled from populations at the northern (FCM) and southern (CAS) boundaries of its geographic range (FCM, foothills of Chinati Mts., Texas, USA; CAS, Castonos, Coahuila, Mexico). Males had higher growth rates as compared to females between the juvenile-to-yearling stages at both sites. Significant differences were also found for yearlings, and between yearling-to-adult stages. Growth rates decreased as a function of increasing age and were lowest in adults, and highest during the juvenile-to-yearling and yearling age classes. Earliest date on which a female was found to contain oviductal eggs was 19 May and 10 June, for the CAS and FCM sites, respectively. No females with oviductal eggs were found between 01 March and mid-May. Most females in reproductive condition had a SVL of 53-61 mm, and 57-64 mm, at the CAS and FCM sites, respectively, indicating that most females attain maturity at an age of 10-11 months. Clutch sizes were significantly smaller for females from the FCM site. Sex ratio was significantly biased toward females Survivorship was highest between yearling and adult age classes. Most lizards were found in areas with creosote and mesquite. These lizards are generalist predators that feed on a wide variety of arthropods.

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