Morphology of trophic eggs and ovarian dynamics in the subsocial bug Adomerus triguttulus (Heteroptera: Cydnidae)

2006 ◽  
Vol 84 (5) ◽  
pp. 723-728 ◽  
Author(s):  
Shin-ichi Kudo ◽  
Taichi Nakahira ◽  
Yutaka Saito
Keyword(s):  
Maternal Care ◽  
Developmental Process ◽  
Size Structure ◽  
Size Variation ◽  
Ecological Significance ◽  
Hatching Time ◽  
Trophic Eggs ◽  
Egg Care ◽  
Ovarian Dynamics ◽  
Care Period

In the subsocial burrower bug, Adomerus triguttulus (Motschulsky, 1886), females produce trophic eggs, which are inviable and serve as a food supply for hatched nymphs, and add them onto egg masses during maternal care. Trophic eggs are expected to be less costly for females to produce and for offspring to consume than viable eggs. Such specialization may be reflected in the size, structure, and developmental process of the eggs. Inviable trophic eggs were smaller than viable eggs, and the intraclutch size variation of the former was larger than that of the latter. The viable eggs always had approximately five micropylar processes at a pole, whereas the trophic eggs mostly lacked them. Active oogenesis was maintained during the maternal egg care period; oocyte development continued after the deposition of viable eggs and declined close to the hatching time of the clutches. Mature chorionated eggs were consistently observed in ovaries. It is strongly suggested that at least some trophic eggs contained in clutches at hatching are those that have matured and been deposited during the maternal care of eggs. We discuss possible selective factors leading to the specialization of these unusual heteropteran trophic eggs and the ecological significance of their ovarian dynamics.

Developmental divergence among hatchery strains of rainbow trout (Salmo gairdneri). I. Pure strains

1985 ◽  
Vol 27 (3) ◽  
pp. 289-297 ◽  
Author(s):  
Moira M. Ferguson ◽  
Roy G. Danzmann ◽  
Fred W. Allendorf
Keyword(s):  
Rainbow Trout ◽  
Morphological Analysis ◽  
Developmental Process ◽  
Developmental Rate ◽  
Electrophoretic Analysis ◽  
Development Rate ◽  
Salmo Gairdneri ◽  
Glucosephosphate Isomerase ◽  
Hatching Time ◽  
Developmental Divergence

We compare the developmental rate of six closely related hatchery strains of rainbow trout. Hatching time, morphological analysis, and the pattern of ontogenetic change in lactate dehydrogenase, malate dehydrogenase, glucosephosphate isomerase, and phosphoglucomutase activities indicate significant differences in developmental rate between strains. There is close concordance among the different measures of developmental rate. Strains with higher levels of heterozygosity, as estimated from electrophoretic analysis of 42 loci, developed faster than less heterozygous strains. The variation in developmental rate in these closely related strains indicates that there is substantial genetic variation affecting the developmental process in rainbow trout.Key words: development rate, intraspecific variation, rainbow trout.

scholarly journals N-terminal VP1 truncations favor T=1 norovirus-like particles

2020 ◽  
Author(s):  
Ronja Pogan ◽  
Victor U. Weiss ◽  
Kevin Bond ◽  
Jasmin Dülfer ◽  
Christoph Krisp ◽  
...  
Keyword(s):  
Particle Production ◽  
Vaccine Development ◽  
Size Structure ◽  
Size Variation ◽  
Native Mass Spectrometry ◽  
Self Assembling ◽  
Process Understanding ◽  
Viral Particles ◽  
Immunological Reactions ◽  
Capsid Protein Vp1

AbstractNoroviruses cause immense sporadic gastroenteritis outbreaks worldwide. Emerging genotypes, which are divided based on VP1 sequence, further enhance this public threat. Self-assembling properties of the human norovirus major capsid protein VP1 are crucial for using virus-like particles (VLPs) for vaccine development. However, there is no vaccine available yet. Here, VLPs from different variants produced in insect cells are characterized in detail using a set of biophysical and structural tools. We are using native mass spectrometry, gas-phase electrophoretic mobility molecular analysis and proteomics to get clear insights into particle size, structure, composition as well as stability. Generally, noroviruses have been known to form mainly T=3 particles. Importantly, we identify a major truncation in the capsid proteins as a likely cause for the formation of merely T=1 particles. For vaccine development, particle production needs to be a reproducible, reliable process. Understanding the underlying processes in capsid size variation will help to produce particles of a defined capsid size presenting antigens consistent with intact virions. Next to vaccine production itself, this would be immensely beneficial for bio-/nano-technological approaches using viral particles as carriers or triggers for immunological reactions.

The Use of Graphical Methods to Estimate Demographic Parameters

1989 ◽  
Vol 69 (2) ◽  
pp. 367-371 ◽  
Author(s):  
Alastair Grant
Keyword(s):  
Undergraduate Students ◽  
Size Structure ◽  
Size Variation ◽  
Demographic Parameters ◽  
Graphical Methods ◽  
Age Classes ◽  
Size Frequency Distribution ◽  
Age Class ◽  
Frequency Histogram ◽  
Size Frequency

The demographic parameters of a population (the number of age-classes present; growth rates; mortality as a function of age and recruitment levels) are of considerable interest to marine biologists. If individuals can be aged from growth rings in their hard parts, then the estimation of demographic parameters is relatively straightforward. If this is not possible, the next best alternative is to tag or mark individuals and use data on the recapture of these to give the information required. For many marine invertebrates, neither of these options is practical and we must resort to estimating the demographic parameters by making assumptions about recruitment and the size variation between individuals of the same age and then infer the age structure of the population from its size structure. This was first done by Petersen (1891) who interpreted each mode on a size/ frequency histogram as representing a single age-class. More recently, extensive use has been made of methods which assume that the sizes of individuals of the same age will be normally distributed. The size/frequency histogram can then be decomposed into a number of normal distributions, each of which represents a single age-class. This can be done graphically (Harding, 1949; Cassie, 1954; Bhattacharya, 1967) or with computerbased numerical methods (Macdonald & Pitcher, 1979). The graphical methods seem to be the most popular and are frequently taught to undergraduate students. The same methods can be used to dissect a size/frequency distribution into components other than age-classes (Harding, 1949), but the principles are the same.

scholarly journals Size structure and fertility in an Eriocnema fulva Naudin (Melastomataceae) population in Southeastern Brazil

2007 ◽  
Vol 67 (4) ◽  
pp. 685-693 ◽  
Author(s):  
PM. Andrade ◽  
FAM. Santos ◽  
FR. Martins
Keyword(s):  
Population Size ◽  
Survival Probability ◽  
Size Structure ◽  
Size Variation ◽  
Fruit Production ◽  
Stem Length ◽  
Southeastern Brazil ◽  
Herbaceous Plant ◽  
Leaf Lamina ◽  
Number Of Leaves

Eriocnema fulva Naudin is an endangered perennial herbaceous plant, endemic to Minas Gerais state, Brazil. This study was conducted in the Jambreiro Forest (19° 58' -59'S and 43° 52' -55' W, 800-1100 m altitude). In an attempt to describe the population size structure and its association with individual fertility, fifteen 1 x 1 m contiguous plots were set. We tagged, counted, and measured a total of 260 individuals in 1997, 1998 and 1999. Young individuals with leaf lamina lengths < 3.4 cm comprised 33% of the total sampled, indicating that the population was reproducing locally. The number of leaves varied significantly, growth differences being detected only after two years of measurements. Stem length was the variable that best showed population size variation. The length of the largest leaf lamina was the best indication of its development phase. Assessing the number of leaves helped to evaluate the alteration in plant size during the study. The probability that individuals with laminas > 10 cm in length did not reproduce was 2.69%. The highest survival probability of the large-sized individuals confirmed the strong correlation between size and survival. The data indicated that size is important for the fertility of E. fulva, and it may be one of the relevant aspects to be considered for analyses of survival probability. The intraspecific competition, which was indicated by negative correlation between fruit production per size unit and density, can affect fertility, as larger plants had higher fruit production.

scholarly journals N-terminal VP1 Truncations Favor T = 1 Norovirus-Like Particles

Vaccines ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 8
Author(s):  
Ronja Pogan ◽  
Victor U. Weiss ◽  
Kevin Bond ◽  
Jasmin Dülfer ◽  
Christoph Krisp ◽  
...  
Keyword(s):  
Capsid Protein ◽  
Particle Production ◽  
Major Capsid Protein ◽  
Vaccine Development ◽  
Size Structure ◽  
Size Variation ◽  
Native Mass Spectrometry ◽  
Self Assembling ◽  
Process Understanding ◽  
Capsid Protein Vp1

Noroviruses cause immense sporadic gastroenteritis outbreaks worldwide. Emerging genotypes, which are divided based on the sequence of the major capsid protein VP1, further enhance this public threat. Self-assembling properties of the human norovirus major capsid protein VP1 are crucial for using virus-like particles (VLPs) for vaccine development. However, there is no vaccine available yet. Here, VLPs from different variants produced in insect cells were characterized in detail using a set of biophysical and structural tools. We used native mass spectrometry, gas-phase electrophoretic mobility molecular analysis, and proteomics to get clear insights into particle size, structure, and composition, as well as stability. Generally, noroviruses have been known to form mainly T = 3 particles. Importantly, we identified a major truncation in the capsid proteins as a likely cause for the formation of T = 1 particles. For vaccine development, particle production needs to be a reproducible, reliable process. Understanding the underlying processes in capsid size variation will help to produce particles of a defined capsid size presenting antigens consistent with intact virions. Next to vaccine production itself, this would be immensely beneficial for bio-/nano-technological approaches using viral particles as carriers or triggers for immunological reactions.

scholarly journals Size-based ecological interactions drive food web responses to climate warming

2018 ◽  
Author(s):  
Max Lindmark ◽  
Jan Ohlberger ◽  
Magnus Huss ◽  
Anna Gårdmark
Keyword(s):  
Life History ◽  
Body Size ◽  
Food Web ◽  
Population Size ◽  
Climate Warming ◽  
Size Structure ◽  
Physiological Responses ◽  
Size Variation ◽  
Food Chains ◽  
Ecological Interactions

AbstractPredicting the impacts of climate change on animal populations and communities requires understanding of feedbacks between direct physiological responses and indirect effects via ecological interactions. Food-dependent body growth and within-species size variation have major effects on dynamics of populations and communities through feedbacks between individual performance and population size structure. Moreover, evidence suggests a link between temperature and population size structure, but we lack an understanding of how this is mediated by species interactions when life history processes are food-dependent. Here, we use a dynamic stage-structured biomass model with food-, size- and temperature-dependent life history processes to assess how temperature affects coexistence, stability and size structure in a tri-trophic food chain. We show that predator biomass densities decline with warming either gradually or in the form of collapses, depending on which consumer life stage they predominantly feed on. Collapses occur when warming destabilizes the community and induces alternative stable states via Allee effects, which emerge when predators promote their own food source through predation. By contrast, warming at low temperatures stabilizes the community as limit cycles turn to fixed point dynamics, unless predators feed only on juveniles. Elevated costs of being large in warmer environments accelerate the decline in predator persistence and mean body size of the community. These results suggest that predator persistence in warmer climates may be lower than previously acknowledged when accounting for size- and food-dependence of life history processes, and that interactions within and between species can mediate the effects of warming on food web stability.SignificanceClimate warming is altering the dynamics and structure of aquatic ecosystems worldwide. Predicting food web reorganization under rising temperatures requires an understanding of physiological responses and ecological interactions of organisms, both of which depend on body size. We show that size variation within species, food-dependent growth and ecological interactions critically affect how food chains respond to warming. Specifically, warming can stabilize or destabilize food chains and expose predators to increased risk of sudden collapses, resulting in alternative stable food web states. Increasing temperatures can cause abrupt reductions in mean community body size, primarily due to loss of top predators. The potential loss of biodiversity and shifts in ecosystem stability are among the major challenges caused by a warming climate.

Effect of Experimental Manipulation of Feeding Conditions on the Population Stucture of Larval Cod (Gadus morhua) and Herring (Clupea harengus).

1996 ◽  
Vol 47 (2) ◽  
pp. 291 ◽  
Author(s):  
AJ Geffen
Keyword(s):  
Standard Deviation ◽  
Population Size ◽  
Gadus Morhua ◽  
Size Structure ◽  
Size Variation ◽  
Experimental Manipulation ◽  
Rate Of Change ◽  
Clupea Harengus ◽  
Final Size ◽  
Population Size Structure

Cod and herring larvae were fed either rotifers or mixtures of rotifers, Artemia, and wild plankton to test the effects of feeding conditions on the development of population size structure. The population size structure at each sample date was characterized by the skewness, the standard deviation of mean length, the coefficient of variation of mean length and the Gini coefficient. The development of size structure through time was characterized by the spreading rate, which is the rate of change in the standard deviation of mean length over time. Larvae fed on a single, small-sized prey item (rotifers) grew slowly, and size variation increased slowly. Larvae fed on mixed prey species showed better growth; the population structure changed more rapidly, and often led to a skewed size distribution dominated by larger individuals. The presence of larger prey items resulted in disproportionate growth rates in the mixed-diet groups. The presence of these faster-growing individuals was the most important factor in determining the shape of the final size distributions and the development of the population size structure.

Body size and sex ratio in emergent stonefly nymphs (Isogenoides olivaceus: Perlodidae): variation between cohorts and populations

1994 ◽  
Vol 72 (8) ◽  
pp. 1371-1375 ◽  
Author(s):  
Roger J. Haro ◽  
Kay Edley ◽  
Michael J. Wiley
Keyword(s):  
Body Size ◽  
Sex Ratio ◽  
Annual Variation ◽  
Sexual Size Dimorphism ◽  
Population Regulation ◽  
Size Variation ◽  
Size Distributions ◽  
Ecological Significance ◽  
Male Size ◽  
Animal Size

The ecological significance of pattern in animal-size distribution has been receiving increased scrutiny in studies of population regulation and individual energetics. However, few studies have assessed differences in size variation between sequential generations or adjacent populations. Annual variation in body size and sex ratio of emergent perlodid stonefly nymphs, Isogenoides olivaceus (Frison) (Plecoptera: Perlodidae), were examined in populations from two Michigan mesic groundwater rivers. Final nymphal body size was estimated from sex-specific length to mass regression relationships using exuviae collected from each site. Sexual size dimorphism accounted for much of the intraspecific size variation within both populations and cohorts: females were larger ([Formula: see text]) than males ([Formula: see text]). Males showed less size variation than females; unlike those for females, size distributions for males were significantly skewed. Secondary sex ratios were female biased in both populations and all cohorts and ranged between 59.1 and 72.8%. Female sex bias increased with relative male size in both populations.

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