Influence of Benthos Life History upon the Estimation of Secondary Production

1979 ◽  
Vol 36 (12) ◽  
pp. 1425-1430 ◽  
Author(s):  
T. F. Waters

Synchrony of cohorts is one of the life history features having most important effects upon the estimation of benthic secondary production, because most methods depend heavily upon recognition of discrete cohorts. The Hynes method, intended to circumvent the necessity of cohort distinction, still depends upon determination of trophic level, voltinism, minimum and maximum sizes, and length of aquatic life. Knowledge of preferred habitat, distribution, and behavior are essential for accurate production estimates. Use of the production:mean standing stock (P/B) ratio (fairly constant at about 5 for cohort P/B of benthic invertebrates) to approximate production from standing stock data, also must account for trophic level, voltinism, and length of aquatic life. Various life history features are compared as to their probable effect on production estimation; in addition, they are compared to the effect of sampling errors. Key words: benthos, life history, production, secondary production, productivity

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.


1960 ◽  
Vol 92 (1) ◽  
pp. 10-20 ◽  
Author(s):  
J. Raine

Since 1947, when the bramble leafhopper, Ribautiana tenerrima (H.-S.) (rubi Hardy, misella 13011.), was first reported in North America near Victoria, B.C., it has become a serious pest in cane fruit plantings on southern Vancouver Island and the lower Fraser Valley. Hoth nymphs and adults suck the sap from the leaves, producing a white stippling on the upper surfaces (Fig. 1). In a dry season a severe infestation causes many leaves to become curled and appear burned. The canes lack vigor and the size of the fruit is reduced. This is a report on a study of the life history and behavior of the species conducted at Victoria from 1953 to 1957.


10.2307/4682 ◽  
1984 ◽  
Vol 53 (3) ◽  
pp. 1037
Author(s):  
H. N. Southern ◽  
R. A. Powell
Keyword(s):  

Genetics ◽  
1993 ◽  
Vol 134 (2) ◽  
pp. 465-474 ◽  
Author(s):  
T E Johnson ◽  
E W Hutchinson

Abstract We have examined crosses between wild-type strains of Caenorhabditis elegans for heterosis effects on life span and other life history traits. Hermaphrodites of all wild strains had similar life expectancies but males of two strains had shorter life spans than hermaphrodites while males of two other strains lived longer than hermaphrodites. F1 hermaphrodite progeny showed no heterosis while some heterosis for longer life span was detected in F1 males. F1 hybrids of crosses between two widely studied wild-type strains, N2 (var. Bristol) and Berg BO (var. Bergerac), were examined for rate of development, hermaphrodite fertility, and behavior; there was no heterosis for these life history traits. Both controlled variation of temperature and uncontrolled environmental variation affected the length of life of all genotypes. Significant G x E effects on life span were observed in comparisons of N2 and Berg BO hermaphrodites, or N2 hermaphrodites and males, or N2 and a Ts mutant strain (DH26). Nevertheless, within an experiment, environmental variation was minimal and life spans were quite replicable.


2019 ◽  
Vol 6 ◽  
Author(s):  
Olle Hjerne ◽  
Susanna Hajdu ◽  
Ulf Larsson ◽  
Andrea S. Downing ◽  
Monika Winder

Spring phytoplankton blooms contribute a substantial part to annual production, support pelagic and benthic secondary production and influence biogeochemical cycles in many temperate aquatic systems. Understanding environmental effects on spring bloom dynamics is important for predicting future climate responses and for managing aquatic systems. We analyzed long-term phytoplankton data from one coastal and one offshore station in the Baltic Sea to uncover trends in timing, composition and size of the spring bloom and its correlations to environmental variables. There was a general trend of earlier phytoplankton blooms by 1–2 weeks over the last 20 years, associated with more sunshine and less windy conditions. High water temperatures were associated with earlier blooms of diatoms and dinoflagellates that dominate the spring bloom, and decreased diatom bloom magnitude. Overall bloom timing, however, was buffered by a temperature and ice related shift in composition from early blooming diatoms to later blooming dinoflagellates and the autotrophic ciliate Mesodinium rubrum. Such counteracting responses to climate change highlight the importance of both general and taxon-specific investigations. We hypothesize that the predicted earlier blooms of diatoms and dinoflagellates as a response to the expected temperature increase in the Baltic Sea might also be counteracted by more clouds and stronger winds. A shift from early blooming and fast sedimenting diatoms to later blooming groups of dinoflagellates and M. rubrum at higher temperatures during the spring period is expected to increase energy transfers to pelagic secondary production and decrease spring bloom inputs to the benthic system, resulting in lower benthic production and reduced oxygen consumption.


Hydrobiologia ◽  
2019 ◽  
Vol 847 (2) ◽  
pp. 443-456 ◽  
Author(s):  
Nathan C. Dorff ◽  
Debra S. Finn

1974 ◽  
Vol 108 (964) ◽  
pp. 805-817 ◽  
Author(s):  
Henry M. Wilbur ◽  
Donald W. Tinkle ◽  
James P. Collins

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