Life history and distribution of mayflies (Ephemeroptera) in some acid streams in south central Ontario, Canada

1991 ◽  
Vol 69 (4) ◽  
pp. 899-910 ◽  
Author(s):  
Donna J. Giberson ◽  
Rosemary J. Mackay

Life histories and distribution of mayflies (Insecta: Ephemeroptera) were investigated in 11 streams in south central Ontario that ranged from highly acidic to circumneutral. At least 29 mayfly species were recorded from the streams, with 16 common enough for life history analysis. Mayfly distribution and diversity were correlated with pH regime and stream size. No mayflies were found in the smallest, most acid stream, and numbers of mayfly species and their relative abundances generally increased with both increasing stream size and stream pH. Incorporation of life cycle information with distributional data enabled us to determine the precise stream-water pH range encountered by different mayfly life stages in the study streams. Generally, during the period of greatest acid stress in the streams (pH depressions associated with spring snowmelt) the mayflies were present in large or dormant stages, which are believed to be more tolerant of lowered pH.

1983 ◽  
Vol 40 (10) ◽  
pp. 1737-1744 ◽  
Author(s):  
Christopher D. Wren ◽  
Hugh R. MacCrimmon

Growth rate and total mercury concentrations were determined in muscle tissue of pumpkinseed sunfish (Lepomis gibbosus) collected from 16 waters in south-central Ontario. Mean water pH ranged from 5.6 to 8.4. Growth rate is correlated positively with lake pH, whereas fish mercury levels are higher at lower pH. Differences in growth rate may be the result of both metal and acid stress in the lower pH waters. Pumpkinseed mercury levels can be accurately described by an equation incorporating chemical and physical lake variables.


2006 ◽  
Vol 34 (2) ◽  
pp. 471-492
Author(s):  
Tiiu Jaago

The article observes how critical times, conditioned by events concurrent with Soviet power and World War II, are currently reflected in life histories of newly independent Estonia. Oral history analysis comprises texts from southern Läänemaa: oral life history interview (2005), written responses to the Estonian National Museum’s questionnaire “The 1949 Deportation, Life as a Deportee” (1999) and a written life history sent to the Estonian Literary Museum’s relevant competition “One Hundred Lives of a Century” (1999). Aiming at historic context, materials from the Estonian Historical Archives and Läänemaa County Archives have been used. The treatment focuses on two issues. First, whether oral and written narratives only differ by the form of presentation or do they also convey different messages (ideologies). Secondly, whether memories and history documents solely complement each other or do they more essentially alter the imaginations obtained from the events. The public is presented with experience narratives on coping under difficult circumstances, both at practical and mental levels. Narratives are presented from a certain standpoint, pursuant to narrators’ convictions, with the main message remaining the same in different presentations. The addition of history sources enables to better observe the evolving of narrative tradition (narration rules) and highlight new questions (hidden in the narrative).


1998 ◽  
Vol 10 (1-3) ◽  
pp. 1-9
Author(s):  
Onno Boonstra ◽  
Maarten Panhuysen

Population registers are recognised to be a very important source for demographic research, because it enables us to study the lifecourse of individuals as well as households. A very good technique for lifecourse analysis is event history analysis. Unfortunately, there are marked differences in the way the data are available in population registers and the way event history analysis expects them to be. The source-oriented approach of computing historical data calls for a ‘five-file structure’, whereas event history analysis only can handle fiat files. In this article, we suggest a series of twelve steps with which population register data can be transposed from a five-file structured database into a ‘flat file’ event history analysis dataset.


Author(s):  
Maren N. Vitousek ◽  
Laura A. Schoenle

Hormones mediate the expression of life history traits—phenotypic traits that contribute to lifetime fitness (i.e., reproductive timing, growth rate, number and size of offspring). The endocrine system shapes phenotype by organizing tissues during developmental periods and by activating changes in behavior, physiology, and morphology in response to varying physical and social environments. Because hormones can simultaneously regulate many traits (hormonal pleiotropy), they are important mediators of life history trade-offs among growth, reproduction, and survival. This chapter reviews the role of hormones in shaping life histories with an emphasis on developmental plasticity and reversible flexibility in endocrine and life history traits. It also discusses the advantages of studying hormone–behavior interactions from an evolutionary perspective. Recent research in evolutionary endocrinology has provided insight into the heritability of endocrine traits, how selection on hormone systems may influence the evolution of life histories, and the role of hormonal pleiotropy in driving or constraining evolution.


2021 ◽  
pp. 025576142199115
Author(s):  
Tim Palmer ◽  
David Baker

This article explores the life histories of virtuoso classical music soloists with particular reference to conservatoire provision. Detailed life-history interviews were conducted with six virtuosi between May 2018 and January 2019. These participants were three singers, two cellists and a concert pianist. Resultant qualitative data were stored in an NVivo software database and understood through a process of analytic induction. Key findings spotlight the significance of Higher Education, a connection between broad creative and cultural interest and musical excellence, and a significant role for conservatoires in diversifying their training and easing transition into the career. The soloists also warned of dangers relating to controlling teachers, loss of autonomy and a need to convey their career realities to students.


2012 ◽  
Vol 22 (1) ◽  
pp. 79-115 ◽  
Author(s):  
Martin Scanlan

This study creates life history portraits of two White middle-class native-English-speaking principals demonstrating commitments to social justice in their work in public elementary schools serving disproportionately high populations of students who are marginalized by poverty, race, and linguistic heritage. Through self-reported life histories of these principals, I create portraits that illustrate how these practitioners draw motivation, commitment, and sustenance in varied, complicated, and at times contradictory ways.


Parasitology ◽  
1959 ◽  
Vol 49 (3-4) ◽  
pp. 374-386 ◽  
Author(s):  
R. J. Thomas

1. The life history of N. battus is described, and a comparative description of the life history of N. filicollis is given.2. The life histories of these two species are compared with those of N. spathiger and N. helvetianus, two closely related species, and are shown to follow the same basic pattern, with minor variations in timing which appear to be specific in nature, and not related to differences in culture methods or host species.3. The pathogenesis of Nematodirus species is discussed and related to the migration of larvae into the intestinal mucosa during development.


1932 ◽  
Vol 57 (1) ◽  
pp. 93-142 ◽  
Author(s):  
Elsie J. Cadman

Since 1860, in which year De Bary published his great work Die Mycetozoen, the investigation of the life-history of members of the Mycetozoa has aroused a considerable amount of interest, and a great deal of important research has been carried out in this connection. The group of organisms is particularly interesting, because it lies on the borderline between plant and animal kingdoms, and it is very possible that a detailed investigation of several species of the Mycetozoa might be of considerable assistance in elucidating certain obscure points in the life-histories of higher members of both the great natural groups. The term “Mycetozoa,” which we owe to De Bary, will be used throughout in preference to the older term “Myxogastres” invented by Fries (32, p. 2), and that of “Myxomycetes” first employed by Link (32, p. 2). “Mycetozoon,” or “fungus-like animal,” is a very appropriate description of a member of the group, since during part of its life-history it exhibits distinctly animal-like characters, and the individuals move rapidly by means of flagella, whilst later, during the development of the sporangium, a plant-like form is assumed. The combination of plant and animal characters has given rise to much discussion as to the position of the Mycetozoa in plant or animal kingdom, and the group has been claimed by both zoologists and botanists.


Author(s):  
Jeffrey A. Hutchings

Life histories describe how genotypes schedule their reproductive effort throughout life in response to factors that affect their survival and fecundity. Life histories are solutions that selection has produced to solve the problem of how to persist in a given environment. These solutions differ tremendously within and among species. Some organisms mature within months of attaining life, others within decades; some produce few, large offspring as opposed to numerous, small offspring; some reproduce many times throughout their lives while others die after reproducing just once. The exponential pace of life-history research provides an opportune time to engage and re-engage new generations of students and researchers on the fundamentals and applications of life-history theory. Chapters 1 through 4 describe the fundamentals of life-history theory. Chapters 5 through 8 focus on the evolution of life-history traits. Chapters 9 and 10 summarize how life-history theory and prediction has been applied within the contexts of conservation and sustainable exploitation. This primer offers an effective means of rendering the topic accessible to readers from a broad range of academic experience and research expertise.


Koedoe ◽  
2004 ◽  
Vol 47 (1) ◽  
Author(s):  
R.F. Terblanche ◽  
H. Van Hamburg

Due to their intricate life histories and the unique wing patterns and colouring the butterflies of the genus Chrysoritis are of significant conservation and aesthetic value. Thisoverview probes into practical examples of butterfly life history research applicable to environmental management of this relatively well-known invertebrate group in South Africa. Despite the pioneer work on life histories of Chrysoritis in the past, more should be done to understand the life history of the butterflies in the wild, especially their natural host plants and the behaviour of adults and larvae. A system of voucher specimens of host plants should be introduced in South Africa. Although various host plant species in nature are used by the members of Chrysoritis, including the Chrysoritis chrysaor group, the choice of these in nature by each species is significant for conservation management and in the case of Chrysoritis aureus perhaps even as a specific characteristic.A revision of the ant genus Crematogaster will benefit the conservation management of Chrysoritis species since some of these ant species may consist of a number of specieswith much more restricted distributions than previously thought. Rigorous quantified tudies of population dynamics of Chrysoritis butterflies are absent and the introductionof such studies will benefit conservation management of these localised butterflies extensively.


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