Potential, realized, and actual fecundity in the crayfish Orconectes immunis from southwestern Ontario

1995 ◽  
Vol 73 (4) ◽  
pp. 672-677 ◽  
Author(s):  
Daniel P. M. Stechey ◽  
Keith M. Somers
Keyword(s):  
Life History ◽  
Abiotic Factors ◽  
Stage Iv ◽  
Reproductive Stage ◽  
Analysis Of Covariance ◽  
Biotic And Abiotic Factors ◽  
Reproductive Losses

Data on crayfish life history are limited to a few populations of only a few species. Herein we examine the size-specific fecundity of a population of Orconectes immunis from southwestern Ontario. We compare log–log regressions of ovarian egg counts, abdominal egg counts, and the number of independent stage IV juveniles with the size of females to estimate reproductive losses associated with egg extrusion and hatching. We contrast these results with data from a Michigan population. Slopes of the three allometric regressions for the Ontario population were significantly greater than zero (P < 0.05); however, the slope for the ovarian egg counts was significantly less than the hypothesized value of 3.0 (P < 0.05), suggesting that ovarian egg counts did not scale volumetrically with size of females. An analysis of covariance indicated that the slope for the ovarian egg counts differed significantly from the slopes for abdominal egg counts and the number of juveniles (P < 0.05), but the latter two regressions were parallel. The proportional decline in fecundity between ovarian and abdominal egg counts could not be estimated unequivocally because the slopes differed. By contrast, the Michigan population exhibited a 35% decline between these stages. A comparison of size-adjusted abdominal egg counts and the number of juveniles revealed a decline of 58% for the Ontario population. The observed differences in size-specific fecundity at each reproductive stage support the hypothesis that each of these parameters summarizes distinct life-history features. The roles of biotic and abiotic factors on crayfish life history warrant further study.

scholarly journals Relative effects of biotic and abiotic factors during early life history on recruitment dynamics: a case study

2017 ◽  
Vol 74 (7) ◽  
pp. 1125-1134 ◽  
Author(s):  
Fan Zhang ◽  
Kevin B. Reid ◽  
Thomas D. Nudds
Keyword(s):  
Life History ◽  
Yellow Perch ◽  
Lake Erie ◽  
Abiotic Factors ◽  
Zooplankton Abundance ◽  
Biotic Factors ◽  
Large Lakes ◽  
Middle Term ◽  
Biotic And Abiotic Factors ◽  
Juvenile Stages

The relative effects of biotic and abiotic factors, and the life-history stages upon which they act to affect fish recruitment, vary among species and ecosystems. We compared the effects of spawning stock biomass, and factors operating at early-term (encompassing the egg, yolk-sac larval, and first few days of swim-up larval stages), middle-term (including the swim-up larval and pelagic juvenile stages), and late-term (over the benthic juvenile stage) on recruitment by yellow perch (Perca flavescens) in the western basin of Lake Erie between 1999 and 2013. Variation of recruitment was mainly driven by middle-term effects. Then, abiotic factors, such as warming rate and wind speed, more strongly affected recruitment than did biotic factors. Among middle-term biotic factors, the top-down effect of yearling walleye (Sander vitreus) abundance was stronger than the bottom-up effect of zooplankton abundance. Similar to marine species, physical processes appear to strongly affect recruitment dynamics of Lake Erie yellow perch over its pelagic larval and juvenile stages, demonstrating the importance of physical and biological processes in understanding fish population dynamics in large lakes.

Differences in population parameters of Rattus norvegicus in urban and rural habitats of central Argentina

Mammalia ◽  
2013 ◽  
Vol 77 (2) ◽  
Author(s):  
Isabel E. Gómez Villafañe ◽  
Regino Cavia ◽  
María Victoria Vadell ◽  
Olga V. Suárez ◽  
María Busch
Keyword(s):  
Life History ◽  
Rattus Norvegicus ◽  
Abiotic Factors ◽  
Life History Strategies ◽  
Population Parameters ◽  
Biotic And Abiotic Factors ◽  
Central Argentina ◽  
Life History Characteristics

AbstractLife history characteristics are influenced by both biotic and abiotic factors of the environment. The aim of this study was to compare the life history strategies of

The characteristics of lifespan in Cheyletidae and its response to environmental factors

Zoosymposia ◽  
2021 ◽  
Vol 20 ◽  
Author(s):  
ZEHUI ZHENG ◽  
BIN XIA
Keyword(s):  
Life History ◽  
Environmental Factors ◽  
Sex Difference ◽  
Growth And Development ◽  
Development Time ◽  
Abiotic Factors ◽  
Biotic And Abiotic Factors ◽  
The Family ◽  
Difference Temperature

This paper provides a survey of a collection of references on life history studies of eight species in the family Cheyletidae. It reviews some factors (including sex difference, temperature, humidity and prey) that affect the development time and lifespan in Cheyletidae. This paper also analyzes the effects these biotic and abiotic factors on the growth and development of cheyletid mites.

scholarly journals Flow cytometric measurements as a proxy for sporulation intensity in the cultured macroalga Ulva (Chlorophyta)

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Omri Nahor ◽  
Cristina F. Morales-Reyes ◽  
Gianmaria Califano ◽  
Thomas Wichard ◽  
Alexander Golberg ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Life Cycle ◽  
Abiotic Factors ◽  
Physiological Status ◽  
Seaweed Cultivation ◽  
Reproductive Growth ◽  
Biotic And Abiotic Factors ◽  
Flow Cytometric ◽  
Abiotic Stimuli ◽  
Fundamental Shift

Abstract Controlling the life cycle of the green macroalga Ulva (Chlorophyta) is essential to maintain its efficient aquaculture. A fundamental shift in cultivation occurs by transforming the thallus cells into gametangia and sporangia (sporulation), with the subsequent release of gametes and zoids. Sporulation occurrence depends on algal age and abiotic stimuli and is controlled by sporulation inhibitors. Thus, quantification of sporulation intensity is critical for identifying the biotic and abiotic factors that influence the transition to reproductive growth. Here, we propose to determine the sporulation index by measuring the number of released gametes using flow cytometry, in proportion to the total number of thallus cells present before the occurrence of the sporulation event. The flow cytometric measurements were validated by manually counting the number of released gametes. We observed a variation in the autofluorescence levels of the gametes which were released from the gametangia. High autofluorescence level correlated to phototactically active behaviour of the gametes. As autofluorescence levels varied between different groups of gametes related to their mobility, flow cytometry can also determine the physiological status of the gametes used as feedstock in seaweed cultivation.

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