Seasonal and long-term variations in the body size of planktonic copepods in the northern Baltic Sea

1995 ◽  
Vol 123 (2) ◽  
pp. 241-250 ◽  
Author(s):  
M. Viitasalo ◽  
M. Koski ◽  
K. Pellikka ◽  
S. Johansson
Keyword(s):  
Body Size ◽  
Baltic Sea ◽  
The Body ◽  
Planktonic Copepods ◽  
Long Term Variations

Effects of alternative and natural prey on body size, locomotion and dispersal of Neoseiulus bicaudus (Acari: Phytoseiidae)

2019 ◽  
Vol 24 (9) ◽  
pp. 1579-1591
Author(s):  
Jie Su ◽  
Min Liu ◽  
Zhen-Shi Fu ◽  
An-Di Zhu ◽  
Jian Ping Zhang
Keyword(s):  
Body Size ◽  
Prey Availability ◽  
Mass Rearing ◽  
Predatory Mite ◽  
The Body ◽  
Alternative Prey ◽  
Negative Effects ◽  
Natural Prey ◽  
Tetranychus Turkestani

Prey are very important for the mass rearing of natural enemies and can affect the efficiency and quality of natural enemy products. Locomotion is important in dispersal of predatory mites on plants, and such activity is affected by body size and prey availability. The study evaluates the effects of prey (alternative prey: Tyrophagus putrescentiae Schrank and natural prey: Tetranychus turkestani Ugarov & Nikolskii) on the body size, locomotion and dispersal of the predatory mite Neoseiulus bicaudus Wainstein. When fed the alternative prey, the body size and locomotion of N. bicaudus were significantly lower than when fed the natural prey. However, the dispersal of N. bicaudus fed the two prey types was similar. The results suggest that long-term feeding on alternative prey could decrease the body size and locomotion of N. bicaudus. Nevertheless, the negative effects of alternative prey did not appear to affect the dispersal of N. bicaudus. The likely reason is that the type of prey does not affect the ability of the predatory mite to locate spider mites. In other words, when it fed alternative prey, N. bicaudus could still successfully disperse and locate spider mite-infested plants in the same way as when fed the natural prey.

Causes and Consequences of Broad-Scale Changes in the Distribution of Migratory Caribou (Rangifer tarandus) of Southern Hudson Bay

ARCTIC ◽  
2015 ◽  
Vol 68 (4) ◽  
pp. 472 ◽  
Author(s):  
Erica J. Newton ◽  
Kenneth F. Abraham ◽  
James A. Schaefer ◽  
Bruce A. Pond ◽  
Glen S. Brown ◽  
...  
Keyword(s):  
Body Size ◽  
Anthropogenic Disturbance ◽  
Rangifer Tarandus ◽  
The Body ◽  
Dietary Quality ◽  
Hudson Bay ◽  
Substantial Change ◽  
Term Data ◽  
Broad Scale

Understanding the factors driving changes in species distributions is fundamental to conservation, but for wide-ranging species this is often complicated by the need for broad-scale observations across space and time. In the last three decades, the location of summer concentrations of migratory caribou (Rangifer tarandus) in southern Hudson Bay (SHB), Canada, has shifted south and east as much as 500 km. We used long-term data (1987 – 2011) to test two hypotheses that could explain the distribution shift: forage depletion and anthropogenic disturbance. Over time and space, we compared the body size of live-captured adult female caribou, dietary quality from fecal nitrogen in July, the location of VHF- and GPS-collared female caribou in July, distribution of all-terrain vehicle (ATV) tracks and caribou tracks in August, and the proximity of collared caribou to sections of the coast with higher ATV activity in spring and summer. The forage depletion hypothesis was supported by greater body size and dietary quality in caribou of the eastern portion of SHB than in western SHB animals in 2009 – 11. The anthropogenic disturbance hypothesis was supported by the negative correlation of the distributions of ATV tracks and caribou tracks on the coast in 2010 and the fact that caribou avoided areas with ATV activity by 10 – 14 km. In 1987, collared caribou were observed largely along the coast in western SHB in mid-July, while in 2009 – 11, they were inland in western SHB and along the coast in eastern SHB. While these locations demonstrate a substantial change in summer distri­bution over three decades, we were unable to differentiate between forage depletion and anthropogenic disturbance as a single causal factor of the distribution shift.

scholarly journals Study on evolution of a predator–prey model in a polluted environment

2021 ◽  
Vol 26 (6) ◽  
pp. 1052-1070
Author(s):  
Bing Liu ◽  
Xin Wang ◽  
Le Song ◽  
Jingna Liu
Keyword(s):  
Body Size ◽  
Function Analysis ◽  
Fitness Function ◽  
Rapid Evolution ◽  
Evolutionary Model ◽  
The Body ◽  
Predator Prey ◽  
Predator Prey Model ◽  
Prey Model

In this paper, we investigate the effects of pollution on the body size of prey about a predator–prey evolutionary model with a continuous phenotypic trait in a pulsed pollution discharge environment. Firstly, an eco-evolutionary predator–prey model incorporating the rapid evolution is formulated to investigate the effects of rapid evolution on the population density and the body size of prey by applying the quantitative trait evolutionary theory. The results show that rapid evolution can increase the density of prey and avoid population extinction, and with the worsening of pollution, the evolutionary traits becomes smaller gradually. Next, by employing the adaptive dynamic theory, a long-term evolutionary model is formulated to evaluate the effects of long-term evolution on the population dynamics and the effects of pollution on the body size of prey. The invasion fitness function is given, which reflects whether the mutant can invade successfully or not. Considering the trade-off between the intrinsic growth rate and the evolutionary trait, the critical function analysis method is used to investigate the dynamics of such slow evolutionary system. The results of theoretical analysis and numerical simulations conclude that pollution affects the evolutionary traits and evolutionary dynamics. The worsening of the pollution leads to a smaller body size of prey due to natural selection, while the opposite is more likely to generate evolutionary branching.

scholarly journals Size matters: relationships between body size, dry weight and ash-free dry weight of common coastal, aquatic invertebrates in the Baltic Sea

2016 ◽  
Author(s):  
Johan Eklöf ◽  
Åsa Austin ◽  
Ulf Bergström ◽  
Serena Donadi ◽  
Britas D H K Eriksson ◽  
...  
Keyword(s):  
Body Size ◽  
Baltic Sea ◽  
Dry Weight ◽  
Negative Influence ◽  
The Body ◽  
Biologically Active ◽  
Power Relationship ◽  
Potential Influence ◽  
The Baltic Sea ◽  
The Baltic

Background. Organism biomass is one of the most important variables in ecological studies, making estimations of organism weight one of the most common laboratory tasks. Biomass of small macroinvertebrates is usually estimated as dry (DW) or ash-free dry weight (AFDW); a laborious and time consuming process, that often can be speeded up using easily measured and reliable proxy variables like wet/fresh weight and/or body size. Another common way of estimating AFDW - which is the most accurate but also time-consuming estimate of biologically active tissue weight - is the use of AFDW/DW ratios or conversion factors. So far, however, these ratios typically ignore the possibility that the relative weight of biologically active vs. non-active support tissue (e.g. protective exoskeleton or shell) - and therefore, also the AFDW/DW ratio - may change with body size, as previously shown for taxa like spiders, vertebrates and trees. Methods. We collected samples of aquatic, epibenthic macroinvertebrates (>1 mm) in 32 shallow bays along a 360 km stretch of the Swedish coast along the Baltic Sea; one of the largest brackish water bodies on Earth. We then estimated statistical relationships between the body size (length or height in mm), dry weight and ash-free dry weight for 14 of the most common taxa; five gastropods, three bivalves, three crustaceans and three insect larvae. Finally, we statistically estimated the potential influence of body size on the AFDW/DW ratio per taxon. Results. For most of the taxa, non-linear regression models describing the power relationship between body size and i) DW and ii) AFDW fit the data well (as indicated by low SE and high R2). Moreover, for more than half of the taxa studied (including the vast majority of the shelled molluscs), body size had a negative influence on organism AFDW/DW ratios. Discussion. The good fit of the modelled power relationships suggest that the constants reported here can be used to more quickly estimate organism dry- and ash-free dry weight based on body size, thereby freeing up considerable work resources. However, the considerable differences in constants between taxa emphasize the need for taxon-specific relationships, and the potential dangers associated with either ignoring body size or substituting relationships between taxa. The negative influence of body size on AFDW/DW ratio found in a majority of the molluscs could be caused by increasingly thicker shells with organism age, and/or spawning-induced loss of biologically active tissue in adults. Consequently, future studies utilizing AFDW/DW (and presumably also AFDW/wet weight) ratios should carefully assess the potential influence of body size to ensure more reliable estimates of organism biomass.

Long-Term Variations in Some Physical Parameters of the Baltic Sea

1984 ◽  
pp. 391-399 ◽  
Author(s):  
Lasse Makkonen ◽  
Jouko Launiainen ◽  
Kimmo Kahma ◽  
Pekka Alenius
Keyword(s):  
Baltic Sea ◽  
Physical Parameters ◽  
The Baltic Sea ◽  
The Baltic ◽  
Long Term Variations

scholarly journals Effects of preweaning nutritional deprivation on basal metabolism and thermoregulatory thermogenesis in the rat

1986 ◽  
Vol 56 (3) ◽  
pp. 615-623 ◽  
Author(s):  
D. V. Muralidhara ◽  
P. S. Shetty
Keyword(s):  
Body Size ◽  
The Body ◽  
Metabolic Efficiency ◽  
Nutritional Rehabilitation ◽  
Adequate Diet ◽  
Nutritional Deprivation ◽  
Short Period ◽  
Body Weights ◽  
Before And After

1. Nutritional deprivation was induced preweaning in Wistar rats by increasing the litter size to sixteen, while paired litters with only five pups served as controls. The nutritionally deprived pups were rehabilitated after weaning by ad lib. access to an adequate diet.2. The body-weights and body lengths were significantly lower in the nutritionally deprived group and significant differences persisted even after 9 weeks of rehabilitation.3. The body temperature of the nutritionally deprived animals was significantly lower than that of their paired controls, both before and following nutritional rehabilitation, except for a short period after weaning when the nutritionally deprived animals were initially given the diet ad lib.4. The resting oxygen consumption of the nutritionally deprived animals was comparable to that of the controls when corrected for metabolic body size, both before and after weaning. Noradrenaline-stimulated increase in 02 consumption (non-shivering thermogenesis; NST) was reduced by 50% at weaning in the nutritionally deprived animals and returned to levels comparable to those of controls within a short period of rehabilitation.5. The decrease in NST capacity seen in the nutritionally deprived animals was associated with an inability to thermoregulate when exposed to cold (5°), resulting in death. Cold-induced thermogenesis (CIT) also reappeared soon after nutritional rehabilitation.6. Reduction in metabolic rate, NST and CIT seen in the animals nutritionally deprived preweaning was short-lived and disappeared soon after nutritional rehabilitation. Rapid reversal of these physiological changes indicates that they do not confer any long-term benefit or change in metabolic efficiency and are unlike the changes in body size and growth which do not completely recover following nutritional rehabilitation.

Long-term, but not short-term, treatment with somatotropin during pregnancy in underfed pigs increases the body size of progeny at birth1

2004 ◽  
Vol 82 (1) ◽  
pp. 93-101 ◽  
Author(s):  
K. L. Gatford ◽  
J. M. Boyce ◽  
K. Blackmore ◽  
R. J. Smits ◽  
R. G. Campbell ◽  
...  
Keyword(s):  
Body Size ◽  
Term Treatment ◽  
The Body ◽  
Short Term ◽  
Short Term Treatment

scholarly journals Behavior and body size modulate the defense of toxin-containing sawfly larvae against ants

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jean-Luc Boevé
Keyword(s):  
Body Size ◽  
Large Body ◽  
The Body ◽  
Larval Body ◽  
Predator Prey ◽  
Sawfly Larvae ◽  
And Behavior ◽  
Toxic Peptides ◽  
Laboratory Bioassays

AbstractThe sawfly larvae of most Argidae and Pergidae (Hymenoptera: Symphyta) species contain toxic peptides, and these along with other traits contribute to their defense. However, the effectiveness of their defense strategy, especially against ants, remains poorly quantified. Here, five Arge species, A. berberidis, A. nigripes, A. ochropus, A. pagana, A. pullata, plus three Pergidae species, Lophyrotoma analis, Lophyrotoma zonalis, Philomastix macleaii, were tested in laboratory bioassays on ant workers mainly of Myrmica rubra. The experiments focused on short-term predator–prey interactions, sawfly survival rate after long-term interactions, and feeding deterrence of the sawfly hemolymph. The larvae of Arge species were generally surrounded by few ants, which rarely bit them, whereas larvae of Pergidae, especially P. macleaii, had more ants around with more biting. A detailed behavioral analysis of Arge-ant interactions revealed that larval body size and abdomen raising behavior were two determinants of ant responses. Another determinant may be the emission of a volatile secretion by non-eversible ventro-abdominal glands. The crude hemolymph of all tested species, the five Arge species and L. zonalis, was a strong feeding deterrent and remained active at a ten-fold dilution. Furthermore, the study revealed that the taxon-specific behavior of ants, sting or spray, impacted the survival of A. pagana but not the large body-sized A. pullata. The overall results suggest that the ability of Arge and Pergidae larvae to defend against ants is influenced by the body size and behavior of the larvae, as well as by chemicals.

scholarly journals Size matters: relationships between body size, dry weight and ash-free dry weight of common coastal, aquatic invertebrates in the Baltic Sea

2016 ◽  
Author(s):  
Johan Eklöf ◽  
Åsa Austin ◽  
Ulf Bergström ◽  
Serena Donadi ◽  
Britas D H K Eriksson ◽  
...  
Keyword(s):  
Body Size ◽  
Baltic Sea ◽  
Dry Weight ◽  
Negative Influence ◽  
The Body ◽  
Biologically Active ◽  
Power Relationship ◽  
Potential Influence ◽  
The Baltic Sea ◽  
The Baltic

Background. Organism biomass is one of the most important variables in ecological studies, making estimations of organism weight one of the most common laboratory tasks. Biomass of small macroinvertebrates is usually estimated as dry (DW) or ash-free dry weight (AFDW); a laborious and time consuming process, that often can be speeded up using easily measured and reliable proxy variables like wet/fresh weight and/or body size. Another common way of estimating AFDW - which is the most accurate but also time-consuming estimate of biologically active tissue weight - is the use of AFDW/DW ratios or conversion factors. So far, however, these ratios typically ignore the possibility that the relative weight of biologically active vs. non-active support tissue (e.g. protective exoskeleton or shell) - and therefore, also the AFDW/DW ratio - may change with body size, as previously shown for taxa like spiders, vertebrates and trees. Methods. We collected samples of aquatic, epibenthic macroinvertebrates (>1 mm) in 32 shallow bays along a 360 km stretch of the Swedish coast along the Baltic Sea; one of the largest brackish water bodies on Earth. We then estimated statistical relationships between the body size (length or height in mm), dry weight and ash-free dry weight for 14 of the most common taxa; five gastropods, three bivalves, three crustaceans and three insect larvae. Finally, we statistically estimated the potential influence of body size on the AFDW/DW ratio per taxon. Results. For most of the taxa, non-linear regression models describing the power relationship between body size and i) DW and ii) AFDW fit the data well (as indicated by low SE and high R2). Moreover, for more than half of the taxa studied (including the vast majority of the shelled molluscs), body size had a negative influence on organism AFDW/DW ratios. Discussion. The good fit of the modelled power relationships suggest that the constants reported here can be used to more quickly estimate organism dry- and ash-free dry weight based on body size, thereby freeing up considerable work resources. However, the considerable differences in constants between taxa emphasize the need for taxon-specific relationships, and the potential dangers associated with either ignoring body size or substituting relationships between taxa. The negative influence of body size on AFDW/DW ratio found in a majority of the molluscs could be caused by increasingly thicker shells with organism age, and/or spawning-induced loss of biologically active tissue in adults. Consequently, future studies utilizing AFDW/DW (and presumably also AFDW/wet weight) ratios should carefully assess the potential influence of body size to ensure more reliable estimates of organism biomass.

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