scholarly journals Locomotion and righting behavior of sea stars: a study case on the bat star Asterina stellifera (Asterinidae)

2021 ◽  
Vol 69 (Suppl.1) ◽  
pp. 501-513
Author(s):  
Pablo-E. Meretta ◽  
Carlos-Renato Rezende-Ventura
Keyword(s):  
Body Size ◽  
Ecological Factors ◽  
Foraging Strategy ◽  
Vertical Surface ◽  
Water Current ◽  
Sea Star ◽  
Sea Stars ◽  
Locomotion Behavior ◽  
Displacement Pattern ◽  
Individual Body

Introduction: The locomotion behavior of an organism involves the integration of aspects like body symmetry, sensory and locomotor systems. Furthermore, various ecological factors seem to be related to locomotion characteristics, such as foraging strategy, migration trends, response to predators and competitors, and environmental stress. Objective: To analyze locomotion and the influence of body symmetry in the crawling and righting movements of the sea star Asterina stellifera. Methods: We carried out laboratory experiments in aquariums in the presence/absence of water current and on a horizontal and vertical surface. Results: The speed is similar to speed in other species of similar size. Both the speed and linearity of displacement were independent of individual body size. A water current leads to faster crawling and straight paths, but there is no rheotaxis: streams do not affect locomotion. Speed and linearity of displacement were independent of individual body size. The displacement pattern described here may be an adaptation of organisms that present dense populations in communities with high prey abundance, as is the case of A. stellifera. Conclusions: Like other asteroids, this species did not show an Anterior/Posterior plane of symmetry during locomotion, or righting movement: it does not tend to bilaterality.

scholarly journals Sea stars generate downforce to stay attached to surfaces

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mark Hermes ◽  
Mitul Luhar
Keyword(s):  
Body Shape ◽  
Control Volume ◽  
Water Channel ◽  
Morphological Plasticity ◽  
The Body ◽  
Sea Star ◽  
Sea Stars ◽  
Hydrodynamic Loads ◽  
Spherical Dome ◽  
Star Models

AbstractIntertidal sea stars often function in environments with extreme hydrodynamic loads that can compromise their ability to remain attached to surfaces. While behavioral responses such as burrowing into sand or sheltering in rock crevices can help minimize hydrodynamic loads, previous work shows that sea stars also alter body shape in response to flow conditions. This morphological plasticity suggests that sea star body shape may play an important hydrodynamic role. In this study, we measured the fluid forces acting on surface-mounted sea star and spherical dome models in water channel tests. All sea star models created downforce, i.e., the fluid pushed the body towards the surface. In contrast, the spherical dome generated lift. We also used Particle Image Velocimetry (PIV) to measure the midplane flow field around the models. Control volume analyses based on the PIV data show that downforce arises because the sea star bodies serve as ramps that divert fluid away from the surface. These observations are further rationalized using force predictions and flow visualizations from numerical simulations. The discovery of downforce generation could explain why sea stars are shaped as they are: the pentaradial geometry aids attachment to surfaces in the presence of high hydrodynamic loads.

scholarly journals Mammalian body size is determined by interactions between climate, urbanization, and ecological traits

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Maggie M. Hantak ◽  
Bryan S. McLean ◽  
Daijiang Li ◽  
Robert P. Guralnick
Keyword(s):  
Body Size ◽  
Resource Availability ◽  
Critical Role ◽  
Size Variation ◽  
Ecological Factors ◽  
Species Traits ◽  
Body Size Variation ◽  
Resource Availability Hypothesis ◽  
Urban Heat ◽  
Thermal Buffering

AbstractAnthropogenically-driven climate warming is a hypothesized driver of animal body size reductions. Less understood are effects of other human-caused disturbances on body size, such as urbanization. We compiled 140,499 body size records of over 100 North American mammals to test how climate and human population density, a proxy for urbanization, and their interactions with species traits, impact body size. We tested three hypotheses of body size variation across urbanization gradients: urban heat island effects, habitat fragmentation, and resource availability. Our results demonstrate that both urbanization and temperature influence mammalian body size variation, most often leading to larger individuals, thus supporting the resource availability hypothesis. In addition, life history and other ecological factors play a critical role in mediating the effects of climate and urbanization on body size. Larger mammals and species that utilize thermal buffering are more sensitive to warmer temperatures, while flexibility in activity time appears to be advantageous in urbanized areas. This work highlights the value of using digitized, natural history data to track how human disturbance drives morphological variation.

The Influence of Current Speed, Body Size and Water Temperature On the Filtration Rate of Five Species of Bivalves

1972 ◽  
Vol 52 (2) ◽  
pp. 345-374 ◽  
Author(s):  
P. R. Walne
Keyword(s):  
Body Size ◽  
Water Temperature ◽  
Filtration Rate ◽  
Current Speed ◽  
Suitable Method ◽  
Water Filtration ◽  
Water Current ◽  
Water Requirements ◽  
Important Species ◽  
Shellfish Culture

The rate of water filtration by bivalves has long excited interest, but it has in practice proved difficult to measure in conditions where the animal is relatively free from constraint. Its estimation is important from a number of aspects: feeding studies; as an indicator of the animal's reaction to its environment; and for predicting the flow of water required for the culture of economically important species. The work reported in this paper started as part of the general programme on shellfish culture in progress at this laboratory. During the development of a suitable method for studying the water requirements it became clear that one factor, water current, had a more important influence than has been generally recognized.

An association between ear and tail morphologies of bats and their foraging style

2011 ◽  
Vol 89 (2) ◽  
pp. 90-99 ◽  
Author(s):  
James D. Gardiner ◽  
Jonathan R. Codd ◽  
Robert L. Nudds
Keyword(s):  
Body Size ◽  
Foraging Strategy ◽  
Aerodynamic Performance ◽  
Variance Analysis ◽  
Flight Performance ◽  
Wing Membrane ◽  
Trade Off ◽  
Scaling Relationships ◽  
Membrane Morphology ◽  
Foraging Flight

Most studies relating bat morphology to flight ecology have concentrated on the wing membrane. Here, canonical variance analysis showed that the ear and tail morphologies of bats also strongly relate to foraging strategy, which in turn is correlated with flight style. Variations in tail membrane morphology are likely to be a trade-off between increases in the mechanical cost of flight and improvements in foraging and flight performance. Flying with large ears is also potentially energetically expensive, particularly at high flight speeds. Large ears, therefore, are only likely to be affordable for slow foraging gleaning bat species. Bats with faster foraging flight styles tend to have smaller ears, possibly to cut the overall drag produced and reduce the power required for flight. Variations in the size of ears and tail membranes appear to be driven primarily by foraging strategy and not by body size, because the scaling relationships found are either weak or not significant. Ear size in bats may be a result of a trade-off between acoustic and aerodynamic performance.

scholarly journals Infection patterns of helminths in Norops brasiliensis (Squamata, Dactyloidae) from a humid forest, Northeastern Brazil and their relation with body mass, sex, host size, and season

2019 ◽  
Vol 56 (2) ◽  
pp. 168-174 ◽  
Author(s):  
D. M. Amorim ◽  
R. W. Ávila
Keyword(s):  
Body Size ◽  
Ecological Factors ◽  
Parasite Load ◽  
Helminth Fauna ◽  
Northeastern Brazil ◽  
Rainfall Regime ◽  
New Host ◽  
Humid Forest ◽  
Host Sex ◽  
New Host Records

SummaryClimatic and ecological factors can influence the parasite load of a host. Variation in rainfall, body size, and sex of the hosts may be related to the abundance of parasites. This study investigated the helminth fauna associated with a population of Norops brasiliensis, together with the effect of host biology (sex, body size, and mass) and variation in rainfall regime on the abundance of helminths. Species of three groups of endoparasites were found (Nematoda, Cestoda, and Trematoda), with nematodes as the most representative taxa with eight species, prevalence of 63.2 %, mean intensity of 4.0 ± 0.58 (1 – 25), and mean abundance of 2.66 ± 0.44 (0 – 25). Nine helminth species are new host records for N. brasiliensis. The nematode Rhabdias sp. had the highest prevalence (53.3 %). There was no significant relationship between abundance of the trematode Mesocoelium monas and host sex or season, although the abundance of this parasite increased significantly with host body size and mass, while abundance of nematodes was related to season and host mass. This study increases the knowledge about the diversity of helminth fauna associated with N. brasiliensis, revealing infection levels of hosts from northeastern Brazil.

Intra-population variability of the non-breeding distribution of southern giant petrels Macronectes giganteus is mediated by individual body size

2018 ◽  
Vol 30 (5) ◽  
pp. 271-277
Author(s):  
Lucas Krüger ◽  
Vitor H. Paiva ◽  
Julia V.G. Finger ◽  
Elisa Petersen ◽  
José C. Xavier ◽  
...  
Keyword(s):  
Body Size ◽  
Habitat Use ◽  
Population Level ◽  
Total Body Length ◽  
South Shetland Islands ◽  
Latitudinal Distribution ◽  
The North ◽  
Wing Load ◽  
Breeding Distribution ◽  
Individual Body

AbstractLiterature reports that body size can be associated with latitudinal distribution, for instance larger animals inhabit higher latitudes and colder habitats. This rule can be applied for species and populations within a species. The potential influence of body size on non-breeding distribution and habitat use at the intra-population level was investigated for southern giant petrels Macronectes giganteus (Gmelin) from Elephant Island, South Shetland Islands. The non-breeding distribution of 23 individuals was tracked, and total body length, culmen length, wing length, wing load and body mass were measured. Positions of core areas were used to estimate the latitudinal distribution of each individual. Smaller individuals were found to be associated more with lower latitudes, where warmer conditions and more coastal and productive waters prevail, whereas large males were associated more with higher latitudes, with colder conditions near sea ice caps, presumably feeding on carrion or preying on penguins. This association reflects a latitudinal gradient, with smaller individuals positioning themselves towards the north, and larger individuals towards the south. In this case, body size, individual distribution and habitat use were found to be associated, highlighting the importance of studying potential effects of individual body size on the ecology of seabirds.

Ecological factors affecting body size of Japanese adolescents

1993 ◽  
Vol 91 (3) ◽  
pp. 299-303 ◽  
Author(s):  
Akira Endo ◽  
Katsuhiko Omoe ◽  
Hitoshi Ishikawa
Keyword(s):  
Body Size ◽  
Ecological Factors ◽  
Factors Affecting ◽  
Japanese Adolescents

?Tethyaster albertensis, a Late Cretaceous (Turonian) sea star from the Cardium Formation, Alberta, Canada

1990 ◽  
Vol 64 (6) ◽  
pp. 1045-1049 ◽  
Author(s):  
Russell L. Hall ◽  
Suzan Moore
Keyword(s):  
North America ◽  
Late Cretaceous ◽  
Sea Star ◽  
Sea Stars ◽  
Peace River ◽  
The North ◽  
The Family ◽  
Cardium Formation ◽  
Northern Alberta ◽  
Limited Change

Although many of the surviving lineages of sea stars appeared during an early Mesozoic radiation of the class and have undergone limited change since then, they have left a very poor fossil record, particularly in the Mesozoic of North America (Blake, 1981). This record from the Late Cretaceous of Alberta is made more significant by the fact that it is apparently only the second occurrence of a member of the family Astropectinidae in the Cretaceous of North America; Lophidiaster silentiensis was described by McLearn (1944) from the Lower Cretaceous (Albian) Hasler Formation, from a now-submerged locality on the Peace River in northern Alberta. All previously recorded fossil sea stars from the North American Cretaceous are representatives of the family Goniasteridae.

scholarly journals Nutrition Labeling Usage Influences Blood Markers in Body-Size Self-Conscious Individuals: The Korean National Health and Nutrition Examination Survey (KNHANES) 2013–2018

2020 ◽  
Vol 17 (16) ◽  
pp. 5769
Author(s):  
Su Yeon Kye ◽  
Kyu-Tae Han ◽  
Sung Hoon Jeong ◽  
Jin Young Choi
Keyword(s):  
Body Mass Index ◽  
Body Image ◽  
Body Size ◽  
National Health ◽  
Size Perception ◽  
Nutrition Labeling ◽  
Nutrition Examination Survey ◽  
Health And Nutrition ◽  
Body Size Perception ◽  
Individual Body

This study analyzed the effects of nutrition labeling and examined whether nutrition labeling usage influences the levels of blood markers, such as high-density lipoprotein cholesterol (HDL-C) and triglyceride (TG) in body-size self-conscious individuals. The dependent variables were HDL-C and TG; the independent variables were the respondents’ awareness of nutrition labeling use, sociodemographic factors, perceived health status, stress, lifestyle, frequency of eating out, family history of hyperlipidemia, survey year, body mass index, total energy intake, and cholesterol levels. Body-size perception was assessed by matching body mass index with subjective body-shape recognition using data from the Korean National Health and Nutrition Examination Survey (2013–2018). Differences were observed in HDL-C and TG levels according to nutrition labeling usage and body-image perception. The group that recognized body image correctly showed high HDL-C and low TG levels when they actively used nutrition labeling, whereas the group that recognized body image incorrectly showed no significant changes in HDL-C and TG levels even when actively using nutrition labeling. The standard nutritional information, which does not consider individual body-size perceptions, has a restrictive effect. Policies should be developed towards tailored intervention strategies considering individual body-size perception.

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